Question

wildcats come in three colours, red, blue and purple. this trait is controlled by a gene with incomplete dominance. a heterozygous individual is purple. what would the genotypes and phenotypes be of the offspring if a blue wildcat crossed with a purple one

Answer 1

The genotypes and phenotypes of the offspring would be:

Parents:

Blue wildcat: bb

Purple wildcat: Bp (heterozygous)

Offspring:

Genotypes:

50% Bp (purple phenotype)

50% bb (blue phenotype)

Phenotypes:

50% purple wildcats

50% blue wildcats

Since the purple phenotype is the result of incomplete dominance, the heterozygous Bp genotype produces an intermediate purple color. Crossing a bb blue wildcat with a Bp purple wildcat will produce offspring with two possible genotypes: Bp (purple) and bb (blue).

The key here is that the purple phenotype is dominant over blue but incomplete dominant (does not completely override the recessive blue allele). So when a blue and purple wildcat mate:

• The purple parent provides one B allele and one p allele to half of the offspring, producing the Bp genotype and purple phenotype.
• The blue parent provides two b alleles to the other half of the offspring, producing the bb genotype and blue phenotype.

So in summary, you'll get a 1:1 ratio of purple to blue offspring, with 50% Bp/purple and 50% bb/blue. The key is understanding that the purple phenotype results from incomplete dominance of the B allele over b.