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lemontea88
Forum Junior  Topics: 14 Posts: 186 |
Hey guys, I came across this really hard question from kaplan's biochem book which i find it difficult to understand.  A man is heterozygous carrier for albinism, and he marries his half cousin (they share the same grandparent). What is the probablility that the couple produce a child with the disorder? (means the child would be homozygous for albinism) What do you guys think is the answer, and why?
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sumeetmultani
| Forum Elite Topics: 47 Posts: 340
1/8 !!!
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sumeetmultani
| Forum Elite Topics: 47 Posts: 340
no...i jus saw the pedigree in book.. and according to that answer is 1/64..and its rite..coz if u see pedigree 1/2 probabilit passese from each parent to their children and at 3rd generation it comes out 1/16 and probility of autosomal recessive is 1/4. so answer is 1/64.
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lemontea88
| Forum Junior Topics: 14 Posts: 186
But shouldnt the 3rd generation be 1/8? And only the 4th generation will it be 1/16?
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sumeetmultani
| Forum Elite Topics: 47 Posts: 340
see here pedigree is different from usual pedigree!! had it been normal pedigree answer would have been 1/8 but here if u see pedigree...   1/2 1/2 take as male and as female...and now complete the pedigree...down u will get 1/2*1/2*1/2*1/2=1/16 multiply 1/16with 1/4 as chance of child of having autosomal recessive disease from each parent
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sumeetmultani
| Forum Elite Topics: 47 Posts: 340
female------male------=======female ! ! 1/2 1/2 ! ! female----- male female ---------male ! ! 1/2 1/2 ! ! male ----------------------female
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lemontea88
| Forum Junior Topics: 14 Posts: 186
Ahh, i think i get what you mean. THanks! 
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