There are 46 chromosomes per individual. During reproduction 23 chromosomes come from each parent. Therefore, there are 2

^{23}(8,388,608) different possible reproductive cells per parent. Each egg could combine with any of the 2

^{23}different sperms, so there are 8,388,608

^{2}or 70,368,744,177,664 (70 trillion) different combinations of people that could result between any human couple.

Aida is not so much one in a million, but 1 in 70 trillion. (This does not take into account random mutation.)

If we were going to look through the catalogue, at one snapshot a second, it would take a million years to see every possible combination.

If Liz and I were any other of the great apes, Aida would be far more unique, 1 in 281,474,976,710,656 (281 trillion) as most of the great apes have 48 chromosomes rather than 46 (one of ours got fused along the way).

Interesting, but I think you vastly under-estimated the number. I'm no biologist, but see the following discussion of meiosis and chromosomal crossover:

ReplyDeletehttp://en.wikipedia.org/wiki/Meiosis

So, for each of the 23 chromosomes you provided, it's not simply a question of did you provide copy A or copy B but which of the probably infininite combinations of A and B did you provide? An accurate calculation would replace the 2 (base of the exponent) with something much, much larger! So, 70 trillion is a gross underestimate, even without random mutation.

Anyway you slice it, however, Aida is more unique and special than we can ever comprehend...

Yeah, I think you're right. The 1 in 70 trillion would be the absolute minimum, but any of the combination of chromosomes would bump that number up way beyond what I was considering. Thanks.

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