Independent assortment happens when a pair of genes separates independently during metaphase I in meiosis. In this stage, there are random combinations of genes that are formed. Genetic variation was made possible because of this principle.

Two other inheritance patterns are incomplete dominance and codominance. Incomplete dominance is one allele is not completely dominant over the other, such as when a white flower and a red flower cross pollinate, they form pink flower. Codominance is when both alleles contribute to the phenotype, such as when a chicken with white feathers cross with a chicken with black feathers, a chicken with speckled black and white feathers form.

Incomplete dominance occurs when there is a blending between two homozygous phenotypes. As a result, the heterozygous phenotype is somewhere in the middle. For example, when a bunny with a black fur is crossed with a bunny with a white fur, their offspring is neither black nor white, but it will have a gray fur.

On the contrary, codominance happens when both alleles are expressed or manifested physically by the heterozygous organism. For example, when a black bunny and a white bunny are crossed, their offspring will exhibit both black and white fur.

Fruit flies are ideal for genetic research because they have the ability to reproduce a large number of offspring quickly. They only have a short life span of 40 to 50 days which allows the scientists to observe a couple of generations in just several months. In addition, their tiny size makes them easy to keep in a laboratory.