? Mixed race inheritance through multiple generations

Genetics as it applies to evolution, molecular biology, and medical aspects.

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mace
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Re: question

Post by mace » Tue Mar 10, 2009 9:04 am

MrMistery wrote:The answer to your question refers to statistics as well as genetics

I am going to consider the trait of skin color, although the rules are the same for any race-specific characteristi. think of it like this. when great-grandma and great-grandpa have a child, if great-grandpa is irish and great-grandma is black then the child will probably be be somewhere in between(because of probabilistic arrangement of choromosomes in independent assortment). If this grandpa marries a grandma that is white, their child will probably be somewhere in between the parents, so a little blacker than a white person, but close. This parent marries a white woman again. Their son will be almost or totally white. Each time it depends on wether you get the gene from one parent or the other. So, if there was one great-grandma that was black and everyone else in the family since was white, then after 5-6 generations it is extremely probable that all the offspring will be white and there is no trace of the orginal black grandma.

Now let's think about a more pragmatic example. A race is not only about skin color, but many other characteristics. Due to the laws of probabilities with large numbers, the original son of the caucasian man and black woman will probably have most of the traits in between the two(most complex racial traits are indeed poligenic). As more and more genes of caucasian people enter the family gene pool, the black great-grandma's genes will slowly dissapear, and after 5-10 generations all traces of her will most likely dissapear.

So to answer your question: yes, inherited genes usually dissapear after many generations, although it is possible for them to remain. It is a matter of chance.



i have question for you about this MrMistery. please check your private email or respond here.

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