Question

In beta fish, a blue tail (B) is dominant over a black tail (b) and a metallic sheen (M) is dominant

over no metallic sheen (m). A female beta fish who is heterozygous for blue tail with no metallic
sheen has offspring with a male who has a black tail and has no metallic sheen. What is the
phenotypic ratio of their offspring?

Answer 1

D) 8 blue tail nonmetallic: 8 black tail nonmetallic

Step-by-step explanation:

The first thing to realize about the problem is that all offspring will be nonmetallic. Both parents are pure recessive for nonmetallic tails; therefore, their offspring cannot have metallic tails. So to find the ratio, use a simple punnet square with Bb and bb. This results in a 50% chance of Bb (blue) and 50% bb (black). So the last answer is correct.