If this pedigree is for an autosomal recessive characteristi

If this pedigree is for an autosomal recessive characteristic, which individuals are definitely heterozygous?

If this pedigree is for an autosomal recessive characteristic, which individuals are definitely heterozygous? I-1, I-2, II-2, II-4, and II-5 I-1, I-2, I-4, III-1 I-1, I-2, II-4, II-5, III-1 II-2, II-4, II-5, II-3 II-2, II-4, II-5, III-1

Solution

the correct option is c

1 and 2 are heterozygous carriers in I because two of their progenies is affected.

2 in II is unaffected so it can be either heterozygous or carrier

4 and 5 in II are offsprings of an affected and unaffected parent so both of them are definitely heterozygous.

1 in III is again the progeny of affected and unaffected parent so it has to be heterozygous again.