Genetic Probability Question
October 31st, 2011 at 8:59:58 AM
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Long-time lurker at wizard of odds.com. I have always wondered about the following:
You may have heard about the Durrants in Britain:
Basically, mixed race parents have 2 sets of twins who are both more or less 1 black and 1 white. Striking.
So I was wondering what would be the possibility of 2 identical twins born outside of one pregnancy.
The human genome has 3Bn or so base pairs. A woman throughout her life will only release about 300 egg cells out of an initial 3-4MM that are initially produced.
So 2 out of 3-4MM cells need to share the same 1.5Bn base pairs of DNA. That then needs to meet up with the identical sperm twice of which there are generally 300MM available at any given time.
It seems to me that there are many more identical sperm, that this is almost like the pulling colored socks out of a bin problems.
You may have heard about the Durrants in Britain:
Basically, mixed race parents have 2 sets of twins who are both more or less 1 black and 1 white. Striking.
So I was wondering what would be the possibility of 2 identical twins born outside of one pregnancy.
The human genome has 3Bn or so base pairs. A woman throughout her life will only release about 300 egg cells out of an initial 3-4MM that are initially produced.
So 2 out of 3-4MM cells need to share the same 1.5Bn base pairs of DNA. That then needs to meet up with the identical sperm twice of which there are generally 300MM available at any given time.
It seems to me that there are many more identical sperm, that this is almost like the pulling colored socks out of a bin problems.
