A diheterozygous individual AaBb was crossed with a homozygous aabb. As a result, there were 4 types

A diheterozygous individual AaBb was crossed with a homozygous aabb. As a result, there were 4 types of offspring in this ratio – AB 25%, Ab 25%, aB 25%, ab25%. Could this be chained inheritance?

Let’s say traits are inherited in a linked state.

An individual with the AaBb genotype produces two types of germ cells – AB and ab. An individual with the aabb genotype is sex cells of the same ab type.

The offspring will be presented in two options:

AaBb – 50%;

aabb – 50%.

The actually obtained splitting of the 1: 1: 1: 1 type does not correspond to the theoretically found one and indicates the independent inheritance of the features indicated in the given problem. The proportion is characteristic of the so-called analyzing crossing of a diheterozygote with a dihomozygote for genes of recessive traits. Let’s consider this option in more detail.

An individual with the AaBb genotype produces four types of germ cells – AB, aB, Ab and ab.

An individual with the aabb genotype is sex cells of the same ab type.

The offspring are represented by options:

AaBb – 25%;

aaBb – 25%;

Aabb – 25%;

aabb – 25%.

This theoretically obtained result corresponds to that specified in the problem statement.

In the presence of crossing over, the percentage would be different, and did not correspond to the 1: 1: 1: 1 ratio.

Answer: this inheritance is not chained.