The Secrets of Life (5 of 5) - Crossover and Chromosome Inversion

An ordinary human has 46 chromosomes in each cell made up of 23 pairs; one half of the chromosomes are inherited from the mother and the other half from the father. In each chromosome, there are hundreds or thousands of genes. But to simplify our discussion, let's assume there are only four genes in a particular pair of chromosome; A, B, C, D in one copy inherited from the mother and A', B', C', D' in the other copy inherited from the father as shown in Figure 1. During the formation of the egg or the sperm, the chromosome pair separates so that the egg or sperm cell contains only one copy of the chromosome. If this egg or sperm combines with a sperm or egg of a partner at time of conception, an embryo of a child will be formed with a full pair of chromosomes. As we can see in this way, genes from only the mother or the father will be inherited to the child (i. e. either the chromosome with genes A, B, C, D or the chromosome with genes A', B', C', D' will be passed down to the child). So there is a possibility that a child inherits characteristics from the mother or the father only, and not from both parents.
Nature plays a wonderful role in this regard. In practice, before the pair of chromosome separates, the two legs of the chromosome line up very closely with each other. Genes in one leg of the chromosome may exchange with the corresponding genes in the other leg of the chromosome (e.g. genes C, D may swap with genes C', D' as in Figure 2). The chromosomes then separate to form the egg or sperm. This process is called crossover which enables the egg or sperm to carry genes from both the mother and the father before conception, and hence enables the child to inherit genes (and hence characteristics) from both parents. With similar reasoning, we can see that a child can inherit genes from all his grandparents, all his great grandparents and great great grandparents back in many generations. Thus, with crossover, a child is able to inherit a little bit of each from any of his ancestors. The exact mechanism of crossover (i.e. when and how crossover will take place and which genes will exchange etc.) is not known. Hence, the exchange of genes is considered at random.

An individual with chromosome inversion has a normal chromosome and a chromosome with some genes inverted as shown in Figure 3. The individual is completely normal as he/she has no extra or missing genes. It does not really matter which order the genes are as long as they are all present. During the formation of the egg or sperm, the two chromosomes line up very closely with each other, and crossover of genes may take place.
If the crossover occurs not in the inverted region (e.g. genes A, D swap with A', D' as in Figure 4) before the chromosomes separate, both the normal leg and the inverted leg of the chromosomes still has the right number of genes. If the egg or sperm formed from the normal leg of the chromosome combines with a sperm or egg of the partner at conception, an embryo with normal chromosomes will be produced. Alternatively, if the egg or sperm formed from the inverted leg of chromosome combines with a sperm or egg of the partner, an embryo with inverted chromosomes will be produced instead.
If crossover occurs in the inverted region (e.g. gene B swaps with C' as in Figure 5) before the chromosomes separate, both the normal leg and the inverted leg of the chromosomes will have an imbalance of genetic material. If the egg or sperm formed from either of these legs combines with a sperm or egg of the partner at conception, an embryo with a faulty pair of chromosomes will be produced.

In summary, when an individual with chromosome inversion has baby, one of three things might happen:
1. the individual passes his/her normal chromosome on in the egg or sperm. The baby will have a completely normal chromosome pattern with the correct number of genes in the correct order.
2. the individual passes his/her inverted chromosome on in the egg or sperm. The baby will inherit the inverted chromosome. However, since the correct amount of genetic material are present, the baby will be perfectly normal and healthy.
3. the individual passes his/her chromosome with an imbalance of genetic material on in the egg or sperm. The baby will inherit a chromosome which carries an incorrect number of genes. This may result in an early miscarriage or stillborn (usually in the first 3 months of pregnancy). The baby, if born, may have problems in his/her physical or intellectual development.
Given the facts that there are hundreds or thousands of genes in a chromosome and inversion usually occurs in a small portion of the chromosome, the probability of crossover in the inverted region is relatively small compared with crossover not in the inverted region. Hence, the probability of having the baby with genetic problem is relatively small. Nevertheless it is not possible to predict which of the three events would occur in a particular pregnancy. It is therefore important to have prenatal testings during the early stage of pregnancy to examine if the baby has inherited the correct amount of chromosome material, and thus to determine if the baby is genetically healthy before his/her birth.

How To Spend To Save

I present below a simple way to save on grocery spending. This is not something new nor anything special. It's just some usual practice undertaken by most retirees and astute housewifes!

1. Prepare your shopping list in advance.
2. Visit shopping mall with presence of both supermarket giants - Coles and Woolworths (see list further below).
3. Have quick tours of these supermarkets in turn, jot down (or memorise if you can) the lower prices between the two for the items you intend to buy.
4. Go to the first supermarket (e.g. Coles), select and buy those items with lower prices. Get the fuel discount voucher for further savings when you make the appropriate amount of purchase.
5. Unload bought items to your car in the car-park.
6. Go to the second supermarket (e.g. Woolworths), select and buy those items with lower prices. Get the fuel discount voucher for further savings when you make the appropriate amount of purchase.
7. Unload bought items to your car in the car-park and go home.

Following are the shopping malls in the Sydney metropolitan area with presence of both Coles and Woolworths. Surprisingly, the supermarkets are usually located fairly close to each other (as shopping malls usually set aside only certain region for groceries). As such, you don't have to spend too much extra of your time to compare prices between the two supermarkets. But the saving could be quite rewarding:

Bauulkham Hill - Stockland
Bondi Junction - Westfield
Brookvale - Warringah Mall
Burwood - Westfield
Campbelltown - Macquarie Square
Carlingford - Carlingford Court
East Garden - Westfield
Hornsby - Westfield
Liverpool - Westfield
Mt. Druitt - Westfield
Parramatta - Westfield
Rouse Hill - Rouse Hill Town Centre
Sylvania - Southgate Shopping Centre
Warriewood - Centro Warriwood

Happy shopping!

The Secrets of Life (4) - Faulty Genes and Close Relations Marriage

An ordinary human has 46 chromosomes in each cell made up of 23 pairs. In each chromosome, there are hundreds and thousands of genes, and it is estimated that there are about 25,000 - 35,000 genes (exact number is not yet known) in a single human cell. Genes may become faulty due various reasons (e.g. inherited from parents, during the formation of egg or sperm or during the lifetime of the individual due aging or radiation etc). As chromosomes come in pairs, genes also come in pairs. A single faulty gene in a chromosome usually will not cause any problems as there is another working copy of the same gene in the other leg of the chromosome. Ordinary human usually has several faulty genes in the body at any time, and the body still functions perfectly normally. Only when both copies of the same gene in both legs of the chromosomes become faulty, then genetic problem occurs which will then affect the health and development of the individual.
During the formation of the egg or sperm, the two legs of each of the 23 pairs of chromosomes separate. The egg or sperm then has only single legs of the 23 pairs of chromosomes. At the time of conception, the egg and the sperm combine to form the first cell of the child. Each leg of the egg will combine with its corresponding counterpart of the sperm forming 23 pairs of chromosomes like the parents. If there is a faulty gene in the chromosome of the egg, AND if there is a SAME faulty gene in the chromosome of the sperm, then the SAME copy of the genes in the chromosome will be faulty resulting in genetic problems in the child.
Given the facts that there are 25,000 - 35,000 genes in human, a healthy human usually has only a few faulty genes and the faulty genes exist randomly, the chance of having a SAME faulty gene during conception (hence causing genetic problems) of two UNRELATED individuals is extremely low. But when the two individuals are close blood relatives, they share a greater proportion of genes in common than unrelated individuals do because they have a common ancestor from whom they inherited their genes. As such, they have a greater chance of having a same faulty gene in common in their chromosomes. When their egg and sperm combine at time of conception, there is a greater risk of having a child with a same copy of faulty genes in the chromosomes and hence a greater risk of having genetic problems.
The table below shows the proportion of genes shared between close blood relatives:

Relationship Type	Relationship	Proportion of Genes in Common
	Twins (雙生兄妹, 姐弟)	All – 100%
First degree relatives	Brother and sister (兄妹, 姐弟)	Half – 50%
Second degree relatives	Half brother and sister (同父異母或同母異父兄妹, 姐弟)	Quarter – 25%
Third degree relatives	Cousins (堂兄妹, 姐弟, 表兄妹, 姐弟)	Eighth – 12.5%

The closer the blood relations (i.e. the lower the degree of relationship), the greater is the proportion in having genes in common, and hence the higher risk of having offspring with genetic problems .........................................

How to Do a (Right) Research

I read this article in a weekly news bulletin of the Knox Grammar School.

The teacher asked his science students to research some of the latest and most amazing genetic developments using new biotechnology procedures.
Jim, Tom and Peter used Google as the search engine on the internet for their work. Jim presented a picture of a mouse with what looks like an human ear growing on its back. His source was from the BBC News. Tom found the same picture in Wikipedia and found it was the Vacanti Mouse. Peter found the same picture in Dr Karl's Great Moments in Science on ABC Science. Each boy used the information from Google to write up a report on the Vacanti Mouse.
While their effort on the research work were all commendable, only one was right!

The questions are:
1. Which boy got it right?
2. How, using the internet, can information be validated?
3. What does this mean for finding 'truth'?

BBC, Wikipedia and ABC are all reputable sources. But they provided different interpretations of this genetically engineered ear growing on the back of a mouse. Among them, the ABC Science program, Dr Karl's Great Moments in Science was correct ....... the others wrong.

So how was this determined?

The best (and correct) way is to go to the source of the work - in this case Dr Vacanti. Search for the original reports by Dr Vacanti, then consider the original reports with those given by sources like BBC, Wikipedia and ABC.

The key is to (try the best to) validate straight from the horse's mouth.

European Debt Crisis (3 of 3) - Solutions! or Solutions?

As the European Debt Crisis deepened towards the end of 2011, European leaders are under tremendous pressure to find ways to contain, if not to solve, the problem. On 26 October, 2011, EU leaders met in Brussels to hold marathon talks and worked through the night into next morning to come up with an agreement described as vital solutions to the huge debt crisis. Essentially, the agreement consisted of three parts:
1. The European private banks holding Greek bonds agreed to write off 50% of their face value. Effectively, this will lower the Greek debts from the expected 180% to 120% of their GDP by 2020. Although the figure is still enormous but now is more sustainable for an economy driven into recession by austerity measures.
2. European banks will be required to raise about 106-billion euros in new capital by June 2012 to increase their holdings of safe assets to 9% of their total capital. This would help protect them against potential losses resulting from any government defaults, and hence avoid any potential bank crisis.
3. The main euro bailout fund - European Financial Stability Fund (EFSF) - will be expanded from 440-billion euros set up earlier this year to 1-trillion euros. This would be sufficient to provide guarantees for bonds issued by countries including Italy and Spain.

The first part provides a short-term action to alleviate Greek's debt burden. By having the European banks writing off 50% of their debts, it would give some breathing space for Greece for some time. But with the still staggering figure of 120% debt to GDP ratio (doubling the EU limit of 60%), coupled with the weakening economy due to the austerity measures imposed on the country in exchange of the EU bailout packages, will Greece be able to repay or reduce its debts by itself?
The second part aims to provide a medium-term firewall to protect European banks from any potential government defaults. However, this is just a target set by the EU leaders. No information is yet available on how to raise the 106-billion euro of fresh capital. Given the banks taking up 50% loss of their Greek bond assets in support of part 1, will the banks be able to further raise that level of capital by June, 2012?
The third part aims to provide a longer-term pool of fund to help bailout euro countries with financial difficulties, especially larger economies like Italy and Spain. But how to boost up the fund to 1-trillion euro is still yet unknown. The head of EFSF traveled to China right after the EU meeting on 26Oct to discuss on possibility of China's contribution as China is one of the few countries with good financial reserves. But will China be willing to invest in this risky business? China may ask for political returns in exchange of their financial contribution if they do invest. Will EU be able to accept? If not, where will the money come from? Further questions may also be asked. Is the 1-trillion euro fund enough given the (seemingly endless) bailouts needed for the debt countries? Is the continual bailout a right strategy to resolve the crisis?

The EU leaders, especially Germany and France, are very determined to maintain the integrity of the EU and the Eurozone. They worked very hard to try to keep Europe intact from disintegrating due to debt problems of eurozone members. They are very anxious and keen in implementing the plan agreed on 26 October, 2011 to resolve the crisis. But with the ever worsening situation in Europe, especially recently with Italy which is the third largest economy in eurozone after Germany and France - an economy too big to be saved, lining up to a brink of falling after Greece, can it really solve the crisis? If not, what are the real solutions?????

Only time will tell!

European Debt Crisis (2) - How and When It Developed

The European Union (EU) was formed in 1995 among a number of European states with the objective of unifying Europe as a single community to promote peace, equality and unity. Since the formation, the lesser advanced countries, especially the so-called PIIGS - Portugal, Ireland, Italy, Greece and Spain, did have their social welfare standards improved, catching up with economically advanced countries like Belgium, France, Germany and Netherlands. Some countries even have gone too far.
Take Greece as an example. A job which pays 55,000 euros in Germany, pays 70,000 euros in Greece, despite Germany being a more productive country. To get around pay restraints in the calendar year, the Greek government simply paid employees a 13th and even 14th monthly salary. Furthermore, the Greek government categorizes certain jobs as arduous which have a retirement age of 55 for men and 50 for women with generous pensions. More than 600 Greek professions somehow managed to get themselves classified as arduous like hairdressers, radio announcers, musicians etc. All these goodies required substantial government funding which far exceeded their national income. Greece had to borrow money to pay for the expenditures via government bonds etc. As a result, national debts gradually built up.
On 1 January, 1999, the EU launched euro as its official currency. Most EU countries (called the eurozone) uses euro as a common currency among themselves. Before the euro, the PIIGS countries had to borrow money at interest rates much higher than the rates at which Germany paid since Germany was an economically better managed country and hence had a very good credit rating and enjoyed low interest rates. When these countries started to use the euro, they could borrow money at interest rates close to that of Germany. So taking advantage of the lower interest rates, they kept borrowing to buy stuffs that they couldn't afford.
Apart from the low interest rates, the inflation in the PIIGS countries was higher than the rate of interest. In simple terms, if the borrowing rate is 3% and the inflation is 5%, one can gain 2% by borrowing to buy things. So borrow and borrow they did. Over the years, PIIGS countries, especially Greece, amassed an enormous amount of debts in euros which then became unmanageable, and made the governments difficult, if not impossible, to repay.
As an indication of the problem, the following shows the deficit to GDP ratios and the debt to GDP ratios of the PIIGS countries (figures being 2010 estimates based on Eurostat - Apr11):

Country	Deficit to GDP (%)	Debt to GDP (%)
Greece	10.5	142.8
Italy	4.6	119
Ireland	32.4	96.2
Portugal	9.1	93
Spain	9.2	60.1

The EU has set limits for member states to have budget deficit not to exceed 3% of GDP and debt level not to exceed 60% of GDP. But unfortunately, these countries simply failed to comply.
And so the problems went on, and finally became a crisis and brought to the world's focus at end 2009. Greece got the worst situation among others. The country hired Wall Street firms, most notably Goldman Sachs, to help hide its debt so as not to run afoul of EU rules. In December, 2009, Greece was forced to admit that its debts were much higher than previously estimated, reaching 300 billion euros, the highest in modern history. Rating agencies started to downgrade Greek banks and government bonds. In the following few months, Greece responded with a series of austerity programs sparkling serious strikes and riots in the streets. Greece's borrowing costs reached yet further record highs.
By May, 2010, euro members and the International Monetary Fund (IMF) provided a 110-billion euro bailout package to rescue Greece. The situation in Ireland also deteriorated, and in November, 2010, the EU and IMF provided a 85-billion euro bailout package to Ireland. Ireland soon passed the toughest budget in the country's history in return.
Attempting to stop the crisis from spreading, in February, 2011, eurozone leaders established a 500-billion European Financial Stability Fund (EFSF) to provide loans to any euro countries with financial difficulty. In April, 2011, Portugal asked for assistance and was provided with a 78-billion euro bailout package. In July, 2011, Greece passed another round of drastic austerity program, and was provided a second bailout package of 109-billion euros, sparkling even more serious civil unrest though.
While bailouts had so far only been provided to Greece, Ireland and Portugal, situations in Spain and Italy began to look worrying, with interests on government bonds rising sharply and credit ratings being downgraded. In September, 2011, Spain passed constitutional amendment to impose rule to keep future budget deficit to strict limit. Italy passed an austerity budget to balance the country's budget by 2013. Italy and Spain, being the third and fourth largest economies in eurozone after Germany and France, were then put under the world's spotlight.
In October, 2011, eurozone finance ministers approved another 8-billion bailout to Greece, which the country needs desperately before running out of cash by 15 December, 2011.
It now seems almost certain that Greece will not be able to repay its debts by itself. Situations in Ireland, Portugal, Spain and Italy are not too better off. Because of the continued downgraded credit ratings, these PIIGS countries find it harder and harder to borrow as lenders will charge more for further loans. Coupled with austerity measures that these countries must take in order to seek assistance from the EU, economies of these countries are contracting. Many European banks, as well as the European Central Bank, own bonds issued by these governments. Should any of them go default (Greece is the most likely one), many of those banks will have big losses. If some of Europe's biggest banks suddenly look dangerously weak, then other banks may hesitate to extend credit to each other, fearing they too could get dragged down. A banking crisis could begin, resulting in recessions in Europe.
The European problem could potentially spread across the Atlantic to the US because US money market funds hold substantial amount of short-term debts of European banks. If European banks can't find lenders to allow them to routinely issue short-term debts, financial markets could start to freeze up, causing turmoil in US money market funds. As the EU and the US are big economic partners, recession in Europe will ultimately lead to a recession in the US. Slower growth in the EU and the US will then hurt the Asian economies which depend on the West to buy their manufactured goods. As a result, the global economy could fall into a profound recession.

European Debt Crisis (1) - Formation of the European Union

After the devastating World War II, major governments of the continental Europe became convinced that the only way to establish a lasting peace was to work together on reducing the competitive pressures leading to conflicts and to unify all European states in the long run. In 1950, the French Foreign Minister, Robert Schuman, proposed an eventual union of all Europe as a single community, the first step of which would be the integration of the coal and steel industries. These natural heavy industries were regarded at that time as the essential engines behind the manufacture of munitions for wars. The aim of the integration was to eliminate the possibility of further wars by pooling these industries together among the member states. Next year in 1951, the European Coal and Steel Community (ECSC) was born when the 6 founding members - Belgium, France, West Germany, Italy, Luxembourg and Netherlands, signed the Treaty of Paris.
Six years later in 1957, the 6 members further sought closer union and signed the Treaties of Rome to create the European Economic Community (EEC) and the European Atomic Energy Community (EAEC) . They undertook to eliminate the trade barrier among themselves by forming a common market. In 1967, the three communities (ECSC, EEC and EAEC) formally merged into the European Community (EC), creating a single Commission, a single Council of Ministers, and the body known today as the European Parliament.
Membership of the EC expanded from the original 6 to 12 members between 1973 and 1986 (with new members Denmark, Ireland, United Kingdom, Greece, Spain and Portugal). In 1992, they signed the Treaty of Maastricht which laid the basis for further forms of cooperation in foreign and defense policy, in judicial and internal affairs, and in the creation of an economic and monetary union - including a common currency. This further integration created the European Union (EU) in 1995. 3 new members, Austria, Finland and Sweden, joined in the same year.
On January 1, 1999, one of the largest steps toward European unification took place with the introduction of the euro as the official currency in the EU. Euro became the unit of exchange for most EU countries except United Kingdom, Denmark and Sweden who decided not to convert their currencies to Euro.
The EU continued to expand with 10 more countries - Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia, joining in 2004. Later in 2007, 2 other countries, Bulgaria and Romania, joined, bringing the total membership to 27 where it stands today (Nov2011).

As of now, members of the EU (27) include:

Austria (1995), Belgium (1951), Bulgaria (2007), Cyprus (2004), Czech Republic (2004), Denmark (1973), Estonia (2004), Finland (1995), France (1951), Germany (1951), Greece (1981). Hungary (2004), Ireland (1973), Italy (1951), Latvia (2004), Lithuania (2004), Luxembourg (1951), Malta (2004), Netherlands (1951), Poland (2004), Portugal (1986), Romania (2007), Slovakia (2004), Slovenia (2004), Spain (1986), Sweden (1995), United Kingdom (1973).

Only 17 of the 27 members of the EU are part of the Eurozone, the name for the collection of EU countries that utilize the euro. Except United Kingdom, Denmark and Sweden, other new members are working toward becoming part of the Eurozone. Eurozone members (17) include:

Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Malta, Netherlands, Portugal, Slovakia, Slovenia, Spain.

The EU's mission is to:
. guarantee peace, freedom and security in and around Europe
. promote and protect democracy and universal rights in Europe and around the world
. strengthen Europe's economy and to promote solidarity around Europe by working in partnership with national, regional and local government
. make it easy for Europe's citizens to live and work throughout the Union
. promote equality and tolerance of diversity in Europe
. promote and facilitate cooperation between Europeans, at individual, local, regional and national level, and in both the public and private sectors
. protect Europe's environment
. ensure that Europe's voice is heard in the world
. listen to its citizens, be accountable to them and work for them in a transparent and decentralised way.

The EU has its own official flag. It consists of a circle of 12 golden stars on a blue background. The number of stars (12) represents completeness while their position in a circle represents unity. The EU adopts Beethoven's Symphony Number 9 'The Ode of Joy' as their official anthem, conveying the idea of freedom, peace and unity.

(extract from http://www.youtube.com/watch?v=vXuhvzbQ5EI&feature=related)

The Fox and the Vineyard

Once upon a time, a fox passed by a vineyard and saw plenty of big and mouth-watering grapes inside. "Let me go and have a great meal." He said to himself. He squeezed himself through the lattice and entered into the vineyard. "I'm so glad I'm in. Yummy! Yummy!" The grapes were so fresh, delicious and juicy and the fox ate and ate and ate. The fox felt very satisfied and wanted to get out of the vineyard. "It was wonderful. Let me go back now." But then he found he had eaten too much and become so fat that he could not get through the lattice. So the fox had to stop eating and drinking for three days and three nights until he became thin again. Finally he squeezed through the lattice and got outside the vineyard. The fox felt disappointed as he discovered he was only what he was before entering the vineyard.

The moral, from one perspective - 'We come with nothing and we leave with nothing. We can't take away any fame and fortune we accrued in life. So, don't take it too serious.'
Or perhaps we look from the other perspective - 'Sometimes it's not the result we should bother, but rather it's the process we should enjoy.'

The Secrets of Life (3) - Genes and Health and Development

There are 25,000 - 35,000 genes (exact number is not yet known) in a single human cell. A gene is a tiny segment of the chromosome that carries the genetic information for human growth and development. Despite tiny, it is made up of a very long sequence of chemical bases: Adenine (A), Guanine, (G), Thymine (T) and Cytosine (C). e.g. TAGGCCCAGTCACTG .......... These bases are grouped into 3-lettered words (e.g. TAG, GCC etc), each producing a particular type of amino acid for the cell. The sequence of the 3-lettered words is arranged specifically to enable the amino acids to assemble in the correct order for the cell to function. A gene is therefore a basic unit containing particular genetic instructions for performing a particular function for human growth and development (e.g. gene HBA1 - Haemoglobin Alpha 1 in chromosome 16 is responsible for producing a protein for the red blood cell). As chromosomes come in pairs, genes also come in pairs.
If some of the chemical bases in the sequence in the gene is changed, a gene mutation (基因突變) occurs. In this case, the normal genetic sequence in the gene is disturbed, causing the gene either not to function or function incorrectly, and hence the gene becomes faulty. Gene mutation may occur in several ways:
A. Spelling change - some chemical bases ('letters') in the genetic sequence are changed.
B. Insertion - extra 'letters' are inserted in the genetic sequence.
C. Deletion - some 'letters' are deleted from the genetic sequence.
D. Repetition - some 'letters' are repeated in the genetic sequence.

	Correct sequence	Faulty sequence
A. Spelling change	TAG GCC CAG CAG TCA CTG	TAG GCC CAG CAG TAA CTG
B. Insertion	TAG GCC CAG CAG TCA CTG	TAG GCC CAG CAG TCC TCA CTG
C. Deletion	TAG GCC CAG CAG TCA CTG	TAG GCC CAG CAG CTG
D. Repetition	TAG GCC CAG CAG TCA CTG	TAG GCC CAG CAG CAG CAG TCA CTG

The cause of gene mutation can be as follows:
1. the faulty genes in the chromosomes are inherited from parents
2. the genes become faulty during the formation of the egg or the sperm
3. the genes become faulty during the lifetime of the individual (e.g. due aging or exposure to radiation etc.)
As genes are in pairs, sometimes a faulty gene in a chromosome may not cause any problem as there is still another working copy of the gene in the other pair of the chromosome. In fact, all normal human usually has several faulty genes in the body at any times, and the body still functions normally. Only that if both copies of the same gene in both pair of chromosomes are faulty, then genetic problem occurs. Sometimes, the fault in a gene is so severe that even there is a working copy of the gene in the other pair of the chromosome, it will still cause genetic problem. Such kind of faulty gene is said to be dominant.
Some examples of common genetic problems due to faulty genes are listed as follows:

Disease	Gene	Symptom
Cystic fibrosis (囊腫性纖維化)	CFTA in chromosome 7	Salty tasting skin, frequent chest infection and coughing or shortage of breath, poor growth and weight gain despite normal food intake
Haemophilia (血友病)	Factor 8 in X chromosome	Continued bleeding due difficulty to clot.
Thalassemia (地中海貧血症)	HBA1/2 in chromosome 16	Ranges from no problem to severe depending on number of genes affected, anaemia (貧血) when severe.
Breast cancer (乳癌)	BRCA1 in chromosome 17 BRCA2 in chromosome 13	Breast lump, change in breast size and shape, inverted nipple
Alzheimer (老人癡呆症)	PS1 in chromosome 14 PS2 in chromosome 1	Difficulty with memory, learning, thinking and reasoning, and undertaking everyday tasks, usually associated with aging.
Parkinson (帕金森病)	PARKIN in chromosome 6	Tremors, stiffness of muscles and slow movements

The above gives some simplistic views on how changes in genes affect the health and development of individuals, in as much as changes in chromosomes do. It is recommended that affected individuals should seek professional advice from genetic counseling on details of medical issues, and implications on any possible inheritance issues when considering births of offspring .............................

某年, 某月, 某曰 寫於羅省機埸

我欲乘機歸去
又恐隨時 off - load
心底不勝寒

此詞寫出一般航空公司職員 (及其家屬), 手持（staff standby) 機票於登機櫃枱前百感交雜之心情; 其中包括: 期待, 渴望, 無助, 無奈, 失落, 擔憂, 抑鬱, 焦慮, 惶恐, 希斯底里, ............................

註 : offload
一般航空公司職員 (及其家屬), 享有特別優惠價錢的（staff) 機票. 惟亦需遵守侯補（standby) 登機之條件. 每次辦理登機手續後, 需於登機櫃枱前等候. 待所有其他乘客完成登記程序, 點算剩餘機位, 才可陸續登機. 假若機位不足, 便不接受上機, 是為 offload.

The Fables of Aesop (伊索寓言) - The Wind and the Sun

Once upon a time, the Wind and the Sun were arguing who was the stronger among them. Suddenly they saw a traveller coming down the road. The Sun said to the Wind, "I see a way to decide our argument. Whoever can cause this traveller to take off his cloak shall be regarded as the stronger." The Wind agreed. The Sun then went away behind the clouds. The Wind began to blow as hard as he could upon the traveller, trying to blow his cloak away from him. But the harder he blew, the more closely the traveller wrapped his cloak around him, until at last the Wind gave up. Then the Sun came out and shone his light and warmth upon the traveller. Finally the traveller felt hot and had to take off his cloak to continue his journey.

Moral : 'Kindness can be more effective than force.'

The Secrets of Life (2) - Chromosomes and Health and Development

Normally every cell of the human body has 46 chromosomes, organized in 23 pairs (22 pairs of autosomes - same for female and male, and one pair of sex chromosomes - XX in female and XY in male). Hence, the chromosomes of an ordinary female is described as 46,XX and a male as 46,XY. During the formation of the egg and the sperm, the chromosome pairs separate so that each egg or sperm cell contains only one copy of the 23 pairs of chromosomes. When the egg and the sperm combine together at the time of conception, they form the first cell of the child which now has 46 chromosomes as the parents. However, during these processes of separation and combination, error may occur resulting in changes in the number, size and structure of the chromosomes. This will then change the amount or the arrangement of genetic information in the cells which may result in problems in health and development of the child:
A. Change in number of chromosomes
Sometimes, mistake may happen in the separation of the chromosome pairs during the formation of the egg or sperm, resulting in either an addition or deletion of chromosomes. When a sperm or egg with the usual 23 chromosomes combine with this egg or sperm with a changed number of chromosomes, it will result in an embryo with chromosomes of number more than or less than the usual number of 46.
Addition and deletion of chromosome have strict rules:
. deletion of any autosome (chromosome 1 - 22) is usually incompatible with life, resulting in miscarriage (流產) or stillborn (胎死腹中) in the first 3 months of pregnancy.
. addition of 2 or more autosomes is also usually incompatible with life in the first 3 months of pregnancy.
. addition of autosome other than chromosome 21 usually results in non-survival in infancy or early childhood (usually within the first year).
. addition or deletion of sex chromosomes (X or Y) is possible except that in the resultant chromosome, there cannot be Y-only chromosomes (i.e. Y chromosome must have an X chromosome in order for survival).
As such, the possible common changes in number of chromosomes and their related effect on the health and development of the child are listed as follows:

Chromosome condition	Description	Syndrome	Symptoms
47,XX+21 47,XY+21	47 chromosomes with extra chromosome 21 in female or male	Down’s syndrome (唐氏綜合症)	Mental retardation, smaller growth parameters including height, neck, head circumference etc., flat face. Usually infertility in male. High risk of miscarriage in female with 50% chance of conceiving babies with Down’s syndrome.
45,X	45 chromosomes with single X chromosome in female	Turner syndrome	Normal intellectual performance, slower growth and lower height, infertility
47,XXY	47 chromosomes with extra X chromosome in male	Klinefelter syndrome	Learning difficulty, tendency to grow at quicker rate, small testcles/penis, infertility
48,XXXY 49,XXXXY	rare extensions with additional X chromosomes) of 47,XXY (male)		More exaggerated features of 47,XXY syndrome
47,XXX	47 chromosomes with extra X chromosome in female	XXX syndrome	‘super-female’, usually no observable physical and medical anomalies apart from being taller than average, normal sexual development, risk of learning difficulty
48,XXXX 49,XXXXX	rare extensions with additional X chromosomes) of 47,XXX (female)		Decreased mental and physical ability, tall texture
47,XYY	47 chromosomes with extra Y chromosome in male	XYY syndrome	‘super-male’, usually no observable physical and medical anomalies apart from being taller than average, normal sexual development., risk of learning difficulty

B. Change in size of chromosomes
Sometimes, a portion of the chromosome is duplicated or deleted during the formation of the egg or sperm, resulting in extra or loss of genetic material in the chromosome. Some common examples and their related effect on the health and development of the child are listed as follows:

Chromosome condition	Description	Syndrome	Symptoms
46,XX,dup(17) (p12)	Duplication of p arm, band 1 and sub band 2 of chromosome 17 in female	Charcot-Marie-Tooth disease (腓骨萎縮症)	Loss of muscle tissues in feet and legs, high arch, claw toes.
46,XX,5p-	Deletion of part of p arm of chromosome 5 in female	Cri-du-chat syndrome (貓哭症)	Intellectual disability, delayed development, small head size, high-pitched cry sound like cat.

C. Change in structure of chromosomes
C.1 Inversion
Sometimes a segment of the chromosome breaks off, rotates 180 degrees and reconnects to the original chromosome during the formation of the egg or sperm. (e.g. 46,XY,inv(12) (p11.2q24.3) refers to a male with inversion in chromosome 12 from p arm band 1, sub-band 1, sub-sub-band 2 to q arm band 2, sub-band 4, sub-sub-band 3.)

Inversion usually does not cause any problems in health and development of the child as there is no gain or loss of genetic material. Only the order of the genetic information is changed. However, there may be complications and problems when the child further has children. We shall leave the discussion of these in a later blog.
C.2 Translocation
Sometimes, segments of 2 chromosomes break off and exchanged during the formation of the egg or sperm. (e.g. 46,XX, t(4,20) (q31,q12) refers to a female with translocation between chromosome 4, long (q) arm band 3, sub-band1 and chromosome 20, long (q) arm band 1, sub-band 2.)

Translocation is much more complicated than inversion as there is an exchange of chromosome segments (i.e. genetic material) between different chromosomes. It may or may not cause problems to the health and development of the child as depending on type of chromosomes involved (e.g. exchange of genetic material between autosome and sex chromosome) and the portion of chromosomes involved.

The above gives some simplistic views on how changes in chromosomes may affect the health and development of the child. It is recommended that affected individuals should seek professional advice from genetic counseling on details of medical issues, and implications on any possible inheritance issues when considering births of offspring ...................

Lightning

Two men were attending a funeral service in a funeral parlour. After having a final view of the diseased in the coffin, one whispered to the other, "I heard poor George was struck by lightning. But why did he smile so brilliantly when he died?" The other replied, "He thought someone was taking a picture of him at that moment!"

The Secrets of Life (1) - Chromosomes, DNA and Genes

Our bodies are made up of millions of cells. Inside the nucleus of each cell, there are chromosomes (染色體). An ordinary human has 46 chromosomes in each cell made up of 23 pairs. The first 44 chromosomes (called autosomes - 常染色體) are numbered 1 to 22 according to size from the largest to smallest. The last 2 chromosomes (called sex chromosomes - 性染色體) could only be either X or Y chromosomes. A female has 2 X chromosomes whereas a male has one X and one Y chromosomes. Hence, a ordinary female's chromosomes are described as 46,XX and male as 46,XY. Usually, a mother passes 23 chromosomes (one from each pair) to her child through her egg and a father likewise passes 23 chromosomes through his sperm. When the egg and the sperm join together at the time of conception, they form the first cell of the child which now has 46 chromosomes as the parents. Hence, one half of the chromosomes are inherited from the mother and the other half from the father. The cell continues to multiply (duplicated from the first cell) as the child continues to grow, resulting in exactly 46 chromosomes in every cell of the body.

Chromosomes, when stretched out, can be as long as 12 centimetres. All of the 46 chromosomes together is about 2 metres long, yet coiled and fit into a single cell nucleus which is about 2 micrometres (0.00002 metres). Each chromosome has a short (p) arm and a long (q) arm separated by a narrow constriction called centromere. Under the microscope and with special stains, the chromosome can be seen as a series of alternate light and dark bands. The bands are labeled p1, p2, p3, q1, q2, q3, etc., counting from the centromere out toward the ends. At higher resolutions, sub-bands (also numbered from the centromere out towards the end) can be seen within the bands. At even higher resolutions, sub-sub-bands can also be seen. The first digit in the band label refers to the band, the second digit the sub-band and the digit after the period the sub-sub-band. For example, a band labelled 16 p13.1 refers to chromosome 16, p-arm, band 1, sub-band 3 and sub-sub-band 1 accordingly.

Chromosomes are made up of material called deoxyribonucleic acid (DNA-脫氧核糖核酸). Thus, each chromosome is a DNA molecule. The DNA molecule is made up of 2 very long chains of 4 chemical units: Adenine (A), Guanine (G), Thymine (T) and Cytosine (C). These 4 chemical units form the bases (as 'letters') of the genetic codes which contain all the information for human growth and development. The bases are arranged in pairs such that A is only paired with T, and G only with C. The bases are further grouped into triplets (e.g. TGA, CTG, ACT etc.) to form '3-lettered words'. Each triplet gives instruction for the cell to produce a particular type of amino acid. A sequence of triplets (e.g. TGACTGACTGTCATG ..... ) enables the cell to assemble the amino acids in the correct order for the cell to function. A complete sequence of triplets that contains particular instructions to perform a particular function is called a gene (基因). Hence, a gene is a basic unit that carries the genetic information for a particular function for human growth and development. Some genes may be responsible for producing certain type of cells like blood, hair or lung etc. Others may be responsible for producing materials with personal characteristics like colour of eye and skin, height or shape of the nose etc. Genes are labelled by their functions. (e.g. gene HBA1, haemoglobin alpha 1 located in chromosome 16, is responsible for producing a protein necessary for red blood cells.)

There are hundreds and thousands of genes in a chromosome, and it is estimated that there are about 25,000 - 35,000 genes in a single human cell. The number of chemical bases (letters A, T, G or C) in a gene varies as dependent on the function of the gene, but may range from 1, 000 to several hundred thousand. In total, there are about 3.1 billion bases (letters) in a single human cell. The arrangement of these 3.1 billion bases is very specific and unique for each individual, and hence the DNA sequence in the cell can be used like a fingerprint for individual identification. When there are changes in the chromosomes or genes (e.g. due errors during the conception of the egg and sperm or external factors like radiation etc.), the normal sequence of genetic codes in the genes (and thus the chromosomes) will be disturbed. Hence, the normal function to produce the necessary materials for the cell to develop will be affected. As result, problems in health and development may occur.

As of today, our knowledge in genes is still quite incomplete (including the exact number of genes and functions of all the genes). But with our increasing knowledge in the secrets of the genetic codes in the genes (and hence the DNA sequence), we can understand more and more about life including how we inherit our personal characteristics from the our parents, the process of aging and deceases and what problems we could expect on health and development. These can well be determined even before birth of the child by appropriate prenatal testings .....................

射鵰英雄傳

最近翻看一部少時喜愛的武俠小說 - 金庸之（射鵰英雄傳）.此書除有吸引人的武俠情節外, 更可看到金庸之文學修養, 及其深湛文筆之功力. 其中一段描寫郭靖, 黃蓉求見當代五大高手（東邪, 西毒, 南帝, 北丐, 中神通）之南帝段皇爺. 南帝當時己歸於佛法, 化名一燈大師, 隱居深山, 不聞世事. 南帝昔日之四大弟子: 漁(漁人), 樵（樵子）, 耕(農夫）, 讀（書生）,為保一燈大師免受滋擾, 各以每人所長, 力阻二人求見. 郭, 黃幾經辛苦, 終於去到最後書生的一關. 書生以其文才, 開出一度難度極高之絕句, 要求二人對出工整之下聯. 能者可繼續上山, 不能者便得知難而退. 其上聯如下：

琴瑟琵琶 八大王一般頭面

黃蓉冰雪聰明, 不消一刻, 己對出非常工整之下聯, 並乘勢嘲諷漁樵耕讀一下. 然後順利過關上山:

魑魅魍魎 四小鬼各自肚腸

其後, 不少文人雅士, 爭相嘗試對岀下聯. 現搜集了一些出色的摘錄如下:

鼴鼮鼫鼬 四賊鼠各踩尾巴 : 鋼鐵銅鋁 四千金不同心腸
烤燴炒炸 四把火旁敲側擊 : 栗桑欒檗 四巨木不同枝葉
駙駿駒馳 四小馬各奔前程 : 猙獰獐狡 四小犬各有面容
閨閣闈閫 四內門各有風光 : 簫筑箏篁 四翠竹各懷清音
懼怕懾憚 四顆心同樣畏縮 : 盯眺盼瞻 四雙目各有看頭
齮齦齟齬 四利齒不一唇舌 : 囚囡囝因 四巨囗各吞一人
珍瑾玲珊 四美玉各領風騷 : 妻妾婆嬰 四嬌女十分麻煩
雷電雪雹 四方雨同等天氣 : 蛇蟺螻蛄 四小虫一般蠢動
挑撥按撚 四纖手別有風姿 : 嫵媚婉妙 四仙女別有風情
倜儻俊俏 四才人別款燦華 : 孫孺孩孤 四男子同等裝扮
飴餃飩餅 四麵食不同餡兒 : 舫舲舴艇 四小舟不同風帆
鵲鴿鴉鵑 四小鳥各自飛翔 : 峭嶇崆峒 四壯山各有形態
貂貉貆獾 四獸豸不盡相同 : 癰疔疽癤 四惡瘡相同爛皮
囚困囹圄 四監牢各關重犯 : 癡癖癲瘋 四狂者各有心疾
雞鴨鵝鴿 四肥鳥各自享用 : 峨嵋崆峒 兩名山譽滿天下

一部武俠小說, 除開故事情節不談, 能夠引起如此的文學迴響, 實不愧為一部不可多得的名著.

至此, 在下亦不禁一時技癢, 附庸風雅一番:

Barry, Benny, Billy, Bobby 四小B同一性別
Ancient History, Business Accounting, Modern Algebra, Visual Arts
四科A一剎光華
John, Vickie, Veronica, Johnson four smart MAN 各有千秋

When In Arabia, Do As The Arabs Do

A disappointed sales manager of Coca-Cola returned from his assignment to Saudi Arabia.
A friend asked, "Why weren't you successful with the Saudis?" The sales manager explained, "When I got posted, I was very confident that I would make a good sales pitch. But I had a problem. I didn't know how to speak Arabic. So I planned to convey the message through three posters."

First poster: A man is lying in the hot desert sand totally exhausted and fainted.
Second poster: A man is drinking Coca-Cola.
Third poster: A man is totally refreshed and lively.
And then these posters were posted all over the place.

"Terrific! That should have worked!" said the friend.
"The hell it should have!" said the sales manager. "But no one told me they read from right to left!"

Think Before You Speak

There were four guys, a French, a Russian, a German and an American, who found a small genie bottle. When they rubbed the bottle, a genie appeared. Thankful that the four guys had released him out of the bottle, the genie said, "I will give each of you a wish. In front of you, there are four swimming pools. When you run towards the pool and jump, you shout what you want the pool of water to become, your wish will come true."
The French started. He ran towards the pool, jumped and shouted, "WINE". There he jumped into a pool of wine.
Next the Russian followed. He ran towards the pool, jumped and shouted, "VODKA". There he jumped into a pool of vodka.
Then it was the German's turn. He ran towards the pool, jumped and shouted, "BEER". There he jumped into a pool of beer.
Lastly it was the American. He ran towards the pool but stepped on a banana peel. He slipped towards the pool and shouted, "SHIT". There he jumped into a pool of ............................

The Monty Hall Problem

You are on a TV show. You are given a choice of 3 doors. Behind one door is a car; behind the others, goats. You are to pick a door, winning whatever is behind it. So you pick one, say door 1. Since there are 2 goats behind 3 doors, whatever you choose, there is at least one goat left behind the 2 other doors. The host, Monty Hall, who knows what's behind them, opens one of these 2 other doors, say door 3, to reveal a goat. He then asks you, "Do you want to stick to your choice, or do you want to switch to door 2?" The question really is to ask, "Does switching increase your chance of winning the car?"
When you pick door 1, the chance of winning the car is 1/3 (i.e. the chance of having the car behind door 1 is 1/3 since there is 1 car in 3 possible doors). And then Monty eliminates door 3 for you by revealing a goat behind door 3. Intuitively, you think you then get a better chance of winning the car as the chance of having the car in door 1 is now 1/2 (since there is 1 car in only 2 possible doors) and likewise in door 2 is also 1/2. So you think it makes no difference whether to switch or not. So you choose to stick with door 1. Right? WRONG!

Let's go back and examine the probabilities in more details.

When you pick door 1, your chance of having the car behind door 1 is 1/3. There's no question about it. Let's now group doors 2 and 3 together. Your chance of having the car NOT behind door 1 (i.e. behind either door 2 or 3) is 2/3 since the total probability must equal to 1. By eliminating door 3 from the scene (by Monty), your chance of having the car behind door 1 is NOT increased from 1/3 to 1/2 as intuitively thought. Your chance of having the car in door 1 is still 1/3 as when you make your choice, you choose 1 out of 3 possibilities (doors 1, 2 and 3). As the saying goes, the dice has been cast. The probability will not, and cannot be altered. Only IF you are free to choose at this point, you are then to choose 1 out of 2 possibilities (doors 1 and 2), and the chance of having the car behind door 1 is indeed 1/2. So by eliminating door 3 from the scene, the effect is ONLY simply changing our group consisting of doors 2 and 3 to a group consisting of door 2 only. Hence your chance of having the car NOT behind door 1 (now behind door 2 only) is still 2/3. In other words, AT THIS POINT, the chance of having the car behind door 2 is 2/3, not 1/2 as intuitively thought. So after Monty eliminates door 3 for you by revealing a goat behind door 3, the chance of having a car in door 1 is 1/3, and in door 2 is 2/3.
Hence, YES, you WILL increase your chance of winning by switching. IN THEORY, YOU SHOULD ALWAYS SWITCH.

Behind the Shadow of The Father

It was a very hot summer day. The whole world seemed to be burning. Inside an air-conditioned clinic, a doctor was still feeling the heat outside. He raised his head and looked through the window. He saw hawkers busy selling their stuff on the street, hustling and bustling under the red hot sun. Before long, he heard very noisy sounds. Several people carried a big fellow into the clinic. The man had already fainted, with sweat all over his body. A little young girl was following and crying.
After the doctor's examination, the man was found to have gotten a sun-stroke. He was then given some water and an injection, and gradually regained his consciousness. Seeing her father recovered, the little girl was relieved despite still sobbing. She took out her purse, put all the money she got on the table and wanted to pay the doctor for the medical treatment. The doctor said, "Forget it. You may take this as a little help from me." The little girl thanked the doctor but continued crying. Trying to cheer up the little girl, the doctor said, "Don't cry, sweetheart. I know you are a strong girl. You were out in the sun all day and you are still okay. Look at your dad, he isn't as strong as you are." The girl cried even more loudly. She said, " No! It's not true! Dad asked me to sit behind his shadow all the time. It was him who stood up there, blocking the sun away from me all day. That's why I'm okay and he's not!"

A father's love is usually straightforward, pragmatic and yet mostly unspoken. Like a mother's love, it is also always dedicated, unconditional and unreserved, and is readily available when you need it. While we usually tend to praise mother's love more, do take a moment to appreciate the love from the father.