Question

A farmer has brown cows with white spots (genotype BBss) and brown cows with no spots (genotype BBSS). If the farmer crossed a brown spotted bull with a brown spotted cow, what percentage of the cows would be black?

Answer 1

About 25%, don't know?

Answer 2

The correct answer would be zero.

From the information provided in the question, we can conclude that brown color (B) is dominant over black (b) and no spots (S) is dominant over spots (s).

In addition, the genotype of the brown spotted cow is also specified as BBss. Thus, only one type of gamete will be produced that is, Bs

Now, the genotype of the brown spotted bull can either be BBss or Bbss. The gamete produced by Bbss will be of two types Bs and bs.

All the offspring produced by crossing BBss and BBss or Bbss will be brown and spotted.

Hence, the probability of black cow would be zero.