Gunpreet, Subject Matter Expert at Edumarz
Answer: The characteristics of all living organisms including human beings are regulated by genes. There are genes in the genome of an individual for each character present such as the body colour, hair colour, eye colour, height, etc. Genes are the basic unit of inheritance that regulates the transmission of characters from one generation to another generation.
In dogs, various coat colours such as black, brown, white, etc. can be seen. These different coat colours are regulated by a variety of genes. Approximately 11 genes have been researched that decide the dog’s coat colour. Now, a gene has a set of two alleles that can be dominant or recessive. A dominant gene expresses itself in both homozygous and heterozygous conditions, whereas a recessive gene expresses itself in a homozygous condition.
To find the dominant coat colour in dogs, let us consider a cross between two parents where one parent is homozygous black (BB) and another parent is homozygous brown (bb). As a result of this cross, offspring with the genetic structure Bb appeared. This first generation is called the F1 generation.
Parents: BB ✖ bb
↓ ↓
Gametes: B b
╳
F1 Generation: Bb
Now we don’t have any idea whether Black is dominant or brown is dominant. But by observing the F1 generation (Bb), we can predict which one is a dominant trait. If the F1 generation comprises all-black offspring, we can say black is a dominant coat colour and if it is brown then we can say brown is the dominant coat colour.