Genes A and B are on the same chromosome. The genes have alleles A and B on one homologous chromosome, and the alleles a and b on its paired homolog. How could an individual with this allele arrangement produce a gamete with a chromosome containing the alleles Ab or aB?

Through the process of crossing-over

Explanation:

During prophase 1 of meiosis, each chromosome carefully pairs with its homologous chromosome. Homologous chromosomes aline together to make the crossing-over possible, the stage where they interchange their parts.

Crossing-over occurs between two homologous chromosomes in the equatorial plane, making the daughter cells genetically different from the original one.

The point where two chromatids interchange their genetic information is the chiasma, where new genetic material or information is produced to be inherited by descendants. Chiasma allows the crossing-over between two homologous chromatids, one of each parent.

The Crossing-over frequency between two genes depends on the distance between them. A short distance between genes is a small target for crossing-over to occur, which means that only a few of them will happen, compared with the number of events between genes that are more separated from each other.

In the exposed example, the chiasma must be placed between A and B genes.

Before crossing-over

The symbol * represents the area where the chiasma places and crossing-over occurs.

After csossing-over