NCERT Solution for Class 10 Science Chapter 9
Heredity and Evolution
NCERT Books for Session 2022-2023
CBSE Board and UP Board
Exercises Questions
Page No-159
Questions No-7
Outline a project which aims to find the dominant coat colour in dogs.
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For this, take a male dog with brown coat and bitch with white coat. Cross them to get the F1 generation. After that, allow the F2 generation to come into being. Tabulate data from two generations and find out the dominant coat colour.
Dogs have a variety of genes that govern coat colour. There are at least eleven identified gene series (A, B, C, D, E, F, G, M, P, S, T) that influence coat colour in dog.
A dog inherits one gene from each of its parents. The dominant gene gets expressed in the phenotype. For example, in the B series, a dog can be genetically black or brown.
Let us assume that one parent is homozygous black (BB), while the other parent is homozygous brown (bb).
In this case, all the offsprings will be heterozygous (Bb).
Since black (B) is dominant, all the offsprings will be black. However, they will have both B and b alleles.
If such heterozygous pups are crossed, they will produce 25% homozygous black (BB), 50% heterozygous black (Bb), and 25% homozygous brown (bb) offsprings.