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Unformatted text preview: recessive, and extremely rare. Franks father and Jamies maternal grandfather were both affected. What is the likelihood of a crazy legged child? Of a crazy legs carrier? You know frank is not a carrier. Having crazylegs: p(frank is XY)*p(Jamie is XX * )*p(no wt X chromosomes in offspring) = (1)*(1/2)*(1/4) = 1/8 Carrier p(frank is XY)*p(Jamie is XX*)*p(offspring is XX*) = (1)*(1/2)*(1/4) = 1/8 Another way to look at it is that there are two possible 2x2 crosses, each with a 50% likelihood: XY x XX and XY x XX* Do both 2x2 crosses to see that only 1 of the 8 cells has a carrier, and only 1 cell has crazylegs. Bonus: What is the likelihood of a child with Michael Jackson Syndrome (both crazy legs and jazz hands)? p(crazylegs)*p(jazzhands)=(1/8)*(1/12)= 1/96...
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- Spring '09