Question

In Betta fish, colored bodies (B) are dominant to white bodies (b), and blue tails (T) are dominant to black tails (t). A Betta fish that is homozygous for having a colored body and a blue tail (BBTT) is crossed with a Betta that is white with a black tail (bbtt). What are the chances of producing an offspring that is white with a blue tail? *

Answer 1

Answer:

0

Explanation:

This question involves two genes in Betta fish; one coding for body color and the other coding for tail colour. The allele for colored body (B) is dominant over the allele for white body (b) in the first gene while allele for blue tail (T) is dominant over allele for black tail (t) in the second gene.

Thus, in a cross between a Betafish that is homozygous dominant for both genes (BBTT) and homozygous recessive for both genes (bbtt), each parent will produce only one type of gamete combination

BBTT- BT

bbtt- bt

Using this in a punnet square, all offsprings will possess a genotype: BbTt.

Since alleles B and T are dominant, a Bettafish with genotype BbTt will be phenotypically color-bodied and blue-tailed.

Hence, according to the question, the probability of producing an offspring with white body and blue tails will be O since no offspring has such genotype.