Suppose an organism had the genotype AABb. What gametes would be produced from this organism?

Sperm and egg cells are called gamete cells or gametes. Gametes are formed during a process called meiosis. Normally cells contain two copies of each chromosome. This means that there are also two copies of each gene. When there are two copies of each chromosome, the cell is said to be diploid (2n). During the process of meiosis, the number of copies of each chromosome in each cell is reduced from two to one. When there is one copy of each chromosome in a cell, the cell is said to be haploid (n). Each cell that undergoes meiosis eventually produces four gamete cells, each containing one copy of each gene. 

The cell that we are interested in has the genotype AABb. This means that both versions of gene “A/a” are the same, while there are different versions of gene “B/b.” Different versions of genes are called alleles. So, for gene “A/a” this cell has two copies of allele A and no copies of allele a. For gene “B/b,” this cell has one copy of allele B and one copy of allele b.

In this case, we are going to assume that gene “A/a” and gene “B/b” are on separate chromosomes. This means that each gene will sort independently without being influenced by the other gene.

Let’s write the genotype of our cell using bold and italic font so that we can keep track of each individual allele: AABb.

Each gamete produced from a cell with this genotype will have one version of gene “A/a” and one version of gene “B/b.” Gene “A/a” can only produce gametes with the allele A. Gene “B/b” can produce gametes with either allele B or allele b.

This means that the geneotypes of the four gamete cells will be: AB, Ab, AB, and Ab. So 50% of the gametes will have the genotype AB and 50% of the gametes will have the genotype Ab.