Feather colour in parakeets is controlled by two genes. Blue colour (B) is dominant over absence of colour (b). Yellow colour (Y) is dominant over absence of colour (y). When a B allele and a Y allele are present, a green parakeet is produced. What is the percent probability of obtaining a yellow or blue parakeet when a heterozygous green parakeet is crossed with a white parakeet? What are the genotypes of the parents?
4 years ago
Answered By Vidhy P
Heterozygous green parakeet has BbYy genotype - possible allele combinations passed down: BY, bY, By, by
White parakeet has bbyy genotype - possible allele combinations passed down: by
When put in a punnet square, total genotypes are: BbYy, bbYy, Bbyy, bbyy
Their phenotype colour, in the above order are: green, yellow, blue, white.
So probability of yellow or blue is 2/4 or 50%. (Parent genotypes were listed above)