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Genes - not the kind you wear!

genes; genetics; genetic; hereditary; relations; traits; DNA; cells; chromosomes; engineering; relatives; clone;

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What are genes?

How embarrassing is it when you haven't seen a friend of the family or a relative for a while, and they say things likeā€¦just like her mum

  • he looks just like his father!
  • he's got your eyes!
  • she's clumsy like our Mary was!
  • she takes after her mother!

Why would they say stuff like that? Well, because your genes, the instructions for making you, come from your mum and her family and your dad and his family.

These genes, 30 to 40 thousand of them, all make up your 23 pairs of chromosomes [say krow-mo-sow-ms]. They are made of DNA [deoxyribonucleic acid, you say it like this - dee-ox-ee-ri-bo-new-clay-ik acid].

So there are going to be traits [say trayts] that you will share with someone in your family in the present or the past.

Traits are things like eye colour, straight or curly hair, shape of features, and other things like skills and abilities.

Where are these genes?

genes pool Every living thing is made up of cells. Each cell has one nucleus, which is the 'boss' of that cell - it tells all the rest of the cell what to do.

Inside each cell there are 23 pairs of chromosomes - that's 46 altogether - which contain all of your genes.

How genes work

Each gene has the instructions on how to make special proteins [say pro-teens] which control how that cell grows and works.

don't blame genes - make good choicesBecause we have two of each chromosome, we also have two of each gene. Since you get one of each pair of chromosomes from each of your parents, you get one gene from each of your parents too.

Suppose that Mary's mum passed on a blond hair gene, and her dad also passed on a blond hair gene - then Mary has 2 genes for blond hair. Guess what colour her hair will be? Yes, blond.

People who breed animals like dogs, cats, horses or even fish and birds try to influence the traits of their animals.

They may cross a dog with a small body to a dog with a different type of coat, eg. a shiatsu with a poodle to make a small dog with a coat like a poodle, instead of the silky coat of a shiatsu.

It isn't quite as easy as that, and it may take a long time and several attempts with several dogs before they manage to breed the changes that they want to make.

In the same way, you will not be exactly like your brothers or sisters (if you have any) because each of you will get a different mix of chromosomes (and genes) from your parents.

Problems with genes

Sometimes the genes from mum and dad can produce problems for the child. Maybe a gene has got altered in some way so that it doesn't work properly.

This can lead to diseases:

  • special types of anaemia, when there are not enough healthy red blood cells
  • or the type of diabetes that adults get.

Other diseases can be inherited through your parents - sometimes diseases which your parents may not get, but a family member (ancestor) who lived many years ago had. Those genes have been handed down in the family.

I inherited my mum's long, slim bones but I also got my dad's funny shaped legs!

Well I guess that's not really a problem. At least they reach the ground and they carry me around!

Genetic engineering technology - 'designing' people?

Scientists are still studying genes and have found out lots about them. They can find the exact gene which is causing some diseases or disabilities. They are experimenting with things like trying to replace a faulty gene with a normal one. This is called gene therapy.

Some people have volunteered to take part in trials which may help themselves and others if the gene replacement works.

Some people think that in the future scientists will be able to swap genes before a baby is born, so that the child will not be born with diseases.

We are not ready to 'design' people, but scientists have 'cloned', or made an exact copy of sheep and other animals.

Dr Kim says:

Dr Kim
Isn't it amazing that each of the billion cells in your body knows how to make an entire person? Isn't it amazing that one tiny gene, too small to see without a very special microscope, can be responsible for me being able to wiggle my nose, just like my mum can?
 

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We've provided this information to help you to understand important things about staying healthy and happy. However, if you feel sick or unhappy, it is important to tell your mum or dad, a teacher or another grown-up.

 

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