Question

For each pedigree below determine the most likely mode of inheritance and label each individual with a genotype. If you know they have a dominant phenotype, but don’t know the genotype, then label them with both possibilities. Please use the alleles A and a. Modes of inheritance for these pedigrees are autosomal dominant or autosomal recessive. For each pedigree determine if the alternative mode (not the one you chose) is also possible.

female = male = III 4 6 IV 1 2 3 4 6 ?

Answer 1

Ans:

The pedigree I shows autosomal recessive mode of inheritance because an affected III-5 female (aa) and a normal III-6 male (AA/Aa) produces a normal IV-5 son (Aa). If it is X-linked, an affected III-5 female (X^•X^•) and a normal III-6 male (XY) cannot produces a normal IV-5 son (XY) because the X chromosome is comes from mother and both the X chromosomes of mother are affected. The trait is recessive because two normal I-1 and I-2 parents (Aa × Aa) produce an affected II-2 son (aa) i. e. an affected individual has unaffected parents and the trait skips generation. If it is dominant, one of the parent must be affected.

2) Г I AR Aa 2 3 4 Q Aa | Aa aa Aa 6 І Aa aa aa AAA - 4 Ч . о N Aa Aa (С А А А Аа Scanned by TapScanner

The pedigree II shows autosomal dominant mode of inheritance because an affected I-1 male (Aa) and a normal I-2 female (aa) produces an affected II-1 son (Aa). If it is X-linked, an affected I-1 male (X^•Y) and a normal I-2 female (XX) cannot produces an affected II-1 son (X^•Y) because the X chromosome is comes from mother and both the X chromosomes of mother are normal. The trait is dominant because the trait doesn't skips generation and each affected individual has one affected parent.

a I Aa 2 5 5 6 8 Aa aa a По по до з" 4 5 А 6 8 П Лола аа Aa Аа аа AA Scanned by TapScanner