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Genetics consanguinity
this is from Genetics Kaplan lectures notes.
A man who is a known heterozygous carrier of oculocutaneous albinism marries his half cousin (they share one common grandparent). This trait is transmitted as a fully penetrant autosomal recessive. What is the probability that this couple will produce a child with this disorder? The answer is 1/64. but I have a question. If they are not relatives , and in the same case (both heterozygous) the probability that this couple produce a child with that disorder will be 1/4 right? So it isn't supposed that consanguinity increase the risk of have the disease? Does anyone coulp explain me this concept plz? 
#2




So, they are not necessarily both heterozygous... Our proband is confirmed heterozygous, but we don't know which parent he got it from or which parent that parent got it from. The chances are:

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#3




yes I agree with that but my question is : if they are cousins like the case the probability is 1/64 but if they weren't relatives the probability will be 1/4 right? let me know if I am wrong. so that mean that consanguinity reduces the probability of disease? How is that? it have no sense for me.



#4




Quote:

#5




ok I got it thx!!

#6




Ohhh woww! Thanksss for explaining

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