Yes, this, one random first cousin marriage probably won't result in anything, but when you have generation after generation marrying and producing children, then you get frequent birth defects. |
Correct. In these cases, it's the father who contributes the faulty gene, which has been duplicated in his sperm. |
It's not clear. It would seem to be both. A shockingly higher than normal percentage of Iranian men are infertile, which would suggest that being the result of a consanguineous pairing has an impact on fertility (the latter proposition in your post). At the same time, a lot of Iranian couples are able to reproduce when a donor egg is introduced or donor sperm is used, suggesting they may be fertile but just unable to reproduce with each other. This would indicate that being too closely related affects people's ability to reproduce with each other (the former proposition in your post). Bottom line: keeping it *out* of the family is a good thing. http://foreignpolicy.com/2014/01/17/the-islamic-republic-of-baby-making/ |
You might be surprised how many states on the coasts allow first cousin marriage:
https://en.m.wikipedia.org/wiki/Cousin_marriage_law_in_the_United_States_by_state Then there's this crazy in New Jersey: http://www.nj.com/news/index.ssf/2015/01/woman_tells_magazine_shes_marrying_her_father_movi.html Aside from potential genetic problems, I imagine that a couple of this sort faces a lot of other issues. |
I had never heard of this. Fascinating! |
I thought that was from marrying DOUBLE first cousins, which is like marrying siblings. |
Bowie's was from an accident not genes. |
I'm 1/2 Ashkenazi jewelry and I have BRCA mutation. I think inbreeding due to geographic isolation was the cause, but not 100% sure on that. I got breast cancer at age 36 and have a 50% chance of passing it on. |
^um supposed to say 1/4 Ashkenazi Jewish. ..damn auto correct |
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I live in Utah and the effects of inbreeding amongst Mormons is startling. It's very strange to see the same faces over and over. And many people do seem slow, although that may be culture as much as IQ. |
Omg, I'm crying from laughter at these two posts. |
Most genetic defects are mutations. They have nothing to do with parents, parents' marriages, and inbreeding. |
Genetic defects are mutations that can be passed on to the offspring. If you have two parents that have the same recessive mutation then they have a 1/4 chance of both passing on that gene to their child and cause the manifestation of the disease in that child. |
On my dad's side, my grandparents were first cousins and so were my great grandparents. (Yes, from Kentucky).
My H and I have a child with a genetic issue but the geneticist said it was most likely not related to my family history. |