Question

In mammoths, assume that spotted skin (S) is dominant over non-spotted skin (s) and that wooly hair (W) is dominant over non-wooly hair (w). Cross a mating between a heterozygous spotted, non-wooly mammoth with a heterozygous wooly-haired, non-spotted mammoth. Give genotypic and phenotypic ratios of offspring.

Answer 1

Genotypic and Phenotypic ratios → 1:1:1:1

• 25% of the progeny is expected to be SsWw, exhibiting spotted skin and wooly hair, SsWw
• 25% of the progeny is expected to be Ssww, exhibiting spotted skin and non-wooly hair, Ssww
• 25% of the progeny is expected to be ssWw, exhibiting non- spotted skin and wooly hair, ssWw
• 25% of the progeny is expected to be ssww, exhibiting non-spotted skin and non-wooly hair, ssww

Step-by-step explanation:

Available data:

• spotted skin (S) is dominant over non-spotted skin (s)
• wooly hair (W) is dominant over non-wooly hair (w)
• Cross: heterozygous spotted, non-wooly mammoth with a heterozygous wooly-haired, non-spotted mammoth.

Parentals) Ssww x ssWw

Gametes) Sw, Sw, sw, sw

sW, sW, sw, sw

Punnett square) Sw Sw sw sw

sW SsWw SsWw ssWw ssWw

sW SsWw SsWw ssWw ssWw

sw Ssww Ssww ssww ssww

sw Ssww Ssww ssww ssww

F1) 4/16 = 1/4 = 25% of the progeny is expected to be SsWw, exhibiting spotted skin and wooly hair

4/16 = 1/4 = 25% of the progeny is expected to be Ssww, exhibiting spotted skin and non-wooly hair

4/16 = 1/4 = 25% of the progeny is expected to be ssWw, exhibiting non- spotted skin and wooly hair

4/16 = 1/4 = 25% of the progeny is expected to be ssww, exhibiting non-spotted skin and non-wooly hair.

Genotypic and Phenotypic ratios → 1:1:1:1