A side note: AFAIK, it isn’t known whether siblings are really 50% identical. They are slightly more than 50% identical with regard to gene expression, because of gene imprinting on the sex chromosomes. It’s possible there’s some weird mechanism that causes an imbalance or bias in recombination. Perhaps we haven’t sequenced enough siblings to know.
Actually, it is clear that siblings share slightly more than 50%. This doesn’t have to do with any fancy issues involving strange things in recombination. They have identical mitochondrial DNA.
So are half-siblings with the same mother more closely related than half-siblings with the same father? Or cousins with mothers who are sisters rather than mothers who are sisters-in-law?
A side note: AFAIK, it isn’t known whether siblings are really 50% identical. They are slightly more than 50% identical with regard to gene expression, because of gene imprinting on the sex chromosomes. It’s possible there’s some weird mechanism that causes an imbalance or bias in recombination. Perhaps we haven’t sequenced enough siblings to know.
Actually, it is clear that siblings share slightly more than 50%. This doesn’t have to do with any fancy issues involving strange things in recombination. They have identical mitochondrial DNA.
So are half-siblings with the same mother more closely related than half-siblings with the same father? Or cousins with mothers who are sisters rather than mothers who are sisters-in-law?
Yes, But this is very rarely relevant because the active part of mitochondrial DNA is almost identical for almost all humans.