Final answer:
Recombination frequency between two genes is calculated as the difference in their map positions in centimorgans (cM), which indicates the percentage of recombination occurring between the genes. This genetic distance helps in constructing genetic maps and understanding gene order on chromosomes.
Step-by-step explanation:
Calculating Recombination Frequency in Genetics
To calculate the recombination frequency between two genes using their coordinates from ENSEMBL database or a genetic map, you need to understand the concept of centimorgans (cM). A centimorgan measures the genetic distance that corresponds to a 1% recombination frequency between genes. If you know the genetic map positions of your genes—for example, gene A is at 48.5 cM and gene B is at 65.5 cM—the recombination frequency can be calculated by subtracting the smaller number from the larger one. In this case, 65.5 cM - 48.5 cM equals 17 cM, meaning there’s an average of 17% recombination between the two genes in the offspring.
It is important to note that recombination frequencies of 0% mean the genes are perfectly linked, and a frequency of 50% indicates the genes are either on different chromosomes or very far apart on the same chromosome and assort independently like in Mendelian inheritance. By examining the frequency of offspring with nonparental genotypes, geneticists can construct genetic linkage maps, which also provide insight on the relative order of genes on a chromosome.