Split Rock
Conflation of Blathers
Hemophilia actually follows X-linked recessive inheritance. Because it is X-linked, it is more prominent in males which have the hemizygous condition, since they only have one X chromosome. Thus, a male only needs one copy, whereas a woman requires two copies. Women who receive the allele, thus become carries of the disease, but rarely get the disease (they would need to get one copy from each parent).Why would natural selection have to happen "within the cell"? That makes no sense.
Let's use hemophilia as our example here. Hemophilia is a deleterious and dominant genetic disease. It only takes a single copy of the disease allele in order to suffer from the disease. It turns out that children are born with the disease, even though neither of their parents has the disease. They have even confirmed through DNA tests that they are the real parents. This means that the mutation that caused hemophilia in these children is a brand new mutation. Nothing stops this mutation from occuring. Nothing would stop this mutation from being passed on to that child's offspring. These mutations have been happening since humans have been on this planet.
This part is correct. Males with hemophilia have historically died young, and therefore do not pass on the gene. In fact, the gene made famous in Queen Victoria's family, and passed on to three different royal lines in Europe (including famously the Tsar's family) was from a new mutation either in Queen Victoria, or one of her parents. There is no evidence of its existence before her issue.So why isn't hemophilia that common? What is stopping the hemophilia allele from being as widespread as the non-disease allele? Why aren't 3/4 of all humans suffering from hemophilia? How do you explain this?
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