Question

Make a Punnett Square to determine the genotypes of the parent guinea pigs if - both have Brown Fur (dominant) and 75% offspring are brown, 25% are white.

Answer 1

Given the 3:1 ratio of brown to white fur in the offspring, the most logical conclusion is that both parent guinea pigs are heterozygous (Bb), carrying both the dominant brown allele and the recessive white allele. This hypothesis is supported by creating a Punnett Square.

Step-by-step explanation:

To determine the genotypes of the parent guinea pigs, considering both have brown fur which is dominant, and the ratio of brown to white fur in the offspring is 3:1, the likely genotypes of the parents would be Bb (for the dominant brown trait) and Bb.

A Punnett Square assists us to visualize this cross:

B (from parent 1)|b (from parent 1)

B (from parent 2)| BB | Bb

b (from parent 2)| Bb | bb

Here BB and two Bb represent brown guinea pigs and bb represents white ones. This gives us the 3:1 ratio mentioned - three out of four offspring are expected to have brown fur (75%) and one out of four is expected to be white (25%). Therefore, both parents are likely heterozygous Bb, carrying both the dominant and recessive alleles.

Learn more about Punnett Square