Question

You are given two true-breeding groups of gerbils. The gerbils in the first group have black fur and curly tails; the gerbils in the second group have yellow fur and straight tails. When you produce an F1 generation, you see only gerbils with black fur and curly tails. When you produce an F2 generation, 75% of the gerbils have black fur and 25% have yellow fur. You also see that 25% of the gerbils have straight tails and 75% have curly tails. If the single alleles responsible for fur color and tail appearance sort independently, how many of the black gerbils in this generation are expected to have straight tails?

Answer 1

Answer:

3 black gebrils have straight tails

Explanation:

Given -

First group of true breeding gebrils have black fur and curly tails

Second group of true breeding gebrils have yellow fur and straight tails

After the F1 generation, all the offspring would have black fur and curly tail

This means black fur is dominant over yellow fur and curly tail is dominant over straight tails

Let "Black fur" be represented by "B" and "yellow fur" be represented by "b"

Let curly tail be represented by "C" and straight tail be represented by "c"

Then parents genotype for F1 generation would be "BBCC" and "bbcc"

and genotype of first generation offspring would be "BbCc"

BbCc

BC         Bc         bC        bc

BC BBCC BBCc BbCC BbCc

Bc BBCc BBcc BbCc Bbcc

bC BbCC BbCc bbCC bbCc

bc BbCc Bbcc bbCc bbcc

Black Curly – BBCC, BBCc, BbCC, BbCc, BBCc, BbCc, BbCC, BbCc, Bbcc,  

Yellow curly- bbCC, bbCc, bbCc

Black straight – BBcc, Bbcc, Bbcc

Yellow straight- bbcc

3 black gebrils have straight tails