Question

in cabbage butterflies, white wings are dominant to yellow wings. If a Ww butterfly is crossed with a ww butterfly , what are the possible genotypes and phenotypes of the offspring and the percent chance for each?

Answer 1

The possible genotypes of this cross are ww (50%) and Ww (50%). Moreover, the possible phenotypes will be white wings (genotype Ww, 50%) and yellow wings (genotype ww, 50%).

An allele is a given gene variant (i.e., a version of a gene).

A homo-zygous individual is an organism that inherited the two same alleles for a given gene/locus, whereas a heterozygous individual inherited two different alleles.

Complete dominance occurs when the presence of an allele called 'dominant allele' completely masks the expression of the recessive allele in heterozygous individuals.

In this case, the parental with the genotype Ww can produce two types of gametes (either W or w) with the same chance of occurring (50%); whereas the parental with the genotype Ww can produce only one type of gamete (w).

In consequence, the progeny of this cross may have a genotype Ww or ww with the same chance of occurring (50%).

The genotype Ww expresses the dominant trait (white wings), whereas the genotype ww expresses the recessive trait (yellow wings).

In conclusion, the possible genotypes of this cross are ww (50%) and Ww (50%). Moreover, the possible phenotypes will be white wings (genotype Ww, 50%) and yellow wings (genotype ww, 50%).