Calculation of the probabilities in a mating involving the ABO blood type

Calculation of the probabilities in a mating involving the ABO blood type and albinism in humans, using the forked-line method

AaI‘IB x AaI‘IB Consideration of pigmentation alone Consideration of blood types alone IEIXIE NEX- i _ —» 1/4 type A i m m —. 3/4 pigmented ——» 2/4 type A5 a 4.1/4 albino 4. 1/4 type B Genotypes Phenotypes Genotypes Phenotypes Of all offspring Of all offspring Final probabilities i i i 1l4 A 3/16 pigmented, type A 3/4 pigmented — 2/4 AB 6/16 pigmented, type AB 1l4 B 3/16 pigmented, type B 1/4 A 1/16 albino, type A 1l4 albino 214 AB 2116 albino, type AB —> 1l4 B 4. 1l16 albino, type B Final phenotypic ratio = 3/16 : 6/16 : 3/16 : 1/16 : 2/16 : 1l16