Question

In cattle, the fur color for brown (b+) and white (b) are being studied by a group of
students. They observe that the white coat color appears in a calf from a cross
between two brown coat colored parents. On the basis of this observation answer the
following question:
a) If the students need to ascertain the genotype of a brown coat colored progeny, .
what would be the best technique to determine the genotype?
b) What would be the genotype of the parent of the white coat colored calf?
c) What are the other possible coat colors which can occur due to the crossing of the
same parents?
d) Draw a flowchart showing the genotypes of the parents and the calf.​

Answer 1

Principles of Inheritance and Variations.

Explanation:

a:

• The graphical representation to calculate the probability of all the possible genotypes offspring in a genetic cross is called Punnet Square.
• The students can determine the genotype of the parent by test cross. Here, the dominant phenotype is crossed with the recessive.

b:

• The genotype of the parents will be heterogenous I.e, the genes will contain both ${b}^{ + } b$.
• This is because the recessive trait is expressed in offspring which was not present in the parents.

c:

• The genotype of the calf will be $bb$.