Question

The allele for a calf having a white coat is recessive while the allele for a brown coat os dominant. Create a Punnett square based on the information given. What do you know about the genetics of the offspring (trait shown and type of organism)?
a. A purebred white cow and a purebred brown bull.

b. A hybrid brown bull and a purebred white cow.

Answer 1

Answer:

a) A purebred white cow and a purebred brown bull.

The parents given are:- bb and BB

B = brown coat - dominant

b = white coat - recessive

The gametes are :-

For bb :- b and b

For BB :- B and B

$\boxed{\begin{tabular}{c|c|c}\bf{-} & \bf{b} & \bf{b}\\\cline{1-3}\bf{B} & Bb & Bb\\\cline{1-3}\bf{B} & Bb & Bb\end{tabular}}$

The genotype of all the progenies will be Bb. That means they are hybrid brown coated.

b) A hybrid brown bull and a purebred white cow.

The parents:- Bb and bb

Gametes:- B, b for Bb and b, b for bb.

Punnet square:-

$\boxed{\begin{tabular}{c|c|c}\bf{-} & \bf{B} & \bf{b}\\\cline{1-3}\bf{b} & Bb & bb\\\cline{1-3}\bf{b} & Bb & bb\end{tabular}}$

The ratio formed here for genotype is 3:1.

One of them is Bb and the rest are bb.

That means one of them is hybrid brown coated and the rest are pure bred white coated.