Final answer:
A map unit or centimorgan (cM) is a unit of genetic distance that corresponds to a 10% recombination frequency. It is used to estimate the relative distance between genes on a chromosome.
Step-by-step explanation:
A map unit or centimorgan (cM) is a unit of genetic distance that corresponds to a 10% recombination frequency. Recombination frequency is a measure of how often two genes on the same chromosome undergo genetic recombination during meiosis. It is used to estimate the relative distance between genes on a chromosome.
For example, if two genes have a recombination frequency of 10%, they are considered to be 10 map units or centimorgans apart. This means that, on average, 10% of the offspring will have a recombination event between these two genes.