Effects of Inbreeding - -9 p(affected because of random...

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Effects of Inbreeding: Today we will examine how inbreeding between close relatives (also known as consanguineous matings) influences the appearance of autosomal recessive traits. Note that inbreeding will not make a difference for dominant traits because they need only be inherited from one parent or for X-linked traits since they are inherited from the mother. Consider an extreme case of inbreeding namely a brother-sister mating. In the U.S. the frequency of 1 st cousin marriages is ≈ 0.001 p (affected because of 1 st cousin mating) = 1 /16 q 10 -3 = 6 . 3 x 10
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Unformatted text preview: -9 p (affected because of random mating) = 10-8 Thus, ~ 1 /3 of affected individuals will come from 1 st cousin marriages Note that this proportion depends on allele frequency such that traits caused by very rare alleles will more often be the result of consanguinity For rare diseases, it is often quite difficult to tell whether or not they are of genetic origin. A useful method to identify disorders that are likely to be inherited is to ask whether an unusually high proportion of affected individuals have parents that are related to one another....
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