Question

The F2 generation phenotypes resulting from the monohybrid cross of purebreds display a ratio of _____.

Answer 1

The ratio will be 3:1

Answer 2

3 Dominant : 1 recessive

Step-by-step explanation:

A monohybrid cross of purebreds is done.

In a monohybrid cross, only one gene is analyzed, and the two individuals being crossed have different phenotypes associated with that gene.

Purebred means that the individuals are homozygous.

We can write the cross as:

AA x aa: both individuals are homozygous and have a different phenotype (one is dominant AA, the other is recessive aa).

The F1 generation will be 100% heterozygous Aa.

To obtain the F2 generation, the F1 is self-crossed.

Aa x Aa

The gametes produced by Aa individuals are A and a.

If you do a Punnett Square, you'll get the following F2 offspring:

• 1 AA
• 2 Aa
• 1 aa

3/4 individuals of the F1 will have a dominant A_ phenotype, and 1/4 individuals will have a recessive aa phenotype.

This is the expected result of Mendel's Law of Dominance.