Dominant and Recessive traits

Last updated at Dec. 13, 2024 by Teachoo

Dominant allele

A dominant allele is the variant of a gene that will produce a certain phenotype and mask the effect of any other variants of the same gene.

The dominant allele can produce its phenotype (trait expression) even in the presence of the other form of allele .
It is represented using capital letters .

A recessive allele is that variant of a gene that does not create a phenotype (trait expression) in the presence of a dominant allele .

We know that an organism receives one copy of each gene from each parent.

There are 3 different possibilities of inheriting the gene.

Let us take the example of hair colour.

In hair colour, dark hair is the dominant trait and blonde hair is the recessive trait.

If both parents pass alleles of dark hair to the child, the child will also have dark hair.

If one parent passes traits of dark hair and another parent passes traits of blonde hair , even then the child will have dark hair.
A dominant trait is always expressed even if one copy of the dominant allele is received from either of the parents

If both parents pass the trait of blonde hair to their child, only then will the child have blonde hair.
Recessive trait is expressed only if both copies of the gene are recessive .

Now, let us take a look at this image once again