Question

In horses, the gene for white face marking has two alleles. The dominant allele (W codes for no white mark, and the recessive allele (w) codes for a white mark. The female horse is homozygous dominant. The male horse is homozygous recessive. Figure out the phenotypes and genotypes of their possible foals by using a punnett square.

Answer 1

This is best explained by first taking the information given to use in the problem and rewording it for our punnet square. The female horse is homozygous dominant, meaning it has two of the W alleles (WW, homozygous meaning same and dominant meaning dominant). The male horse is homozygous recessive, meaning it has two w alleles (ww, same reasoning as above). When crossed (WW x ww) in a punnet square, you get a W and a w crossed in each portion, meaning that there is a 100%, or 4/4, chance that their offspring will be heterozygotes, or Ww. As for phenotype, the W allele (no white marking) is dominant over the w allele