AP BIOLOGY

Detailed explanation-1: -Centimorgan (cM)/ Map unit is the unit used to express the physical distance between the genes. 1cM equals 1% Recombination frequency. Thus we can calculate the map distance of genes on a chromosome, if we know the percentage of recombinants in the offspring.

Detailed explanation-2: -As shown in the next video, the map distance between loci B and E is determined by the number of recombinant offspring. Remember: The # of recombinant offspring / total # of offspring x 100% = recombination frequency. Recombination frequency = map units = centiMorgan (cM)

Detailed explanation-3: -Map units can be determine by calculating the percent recombination (recombination frequency) between the two genes on the chromosome. One percent recombination is equal to one map unit, two percent recombination is equal to two map units, and so forth.

Detailed explanation-4: -The crossover percentage determines the frequency of recombination between gene pairs on the same chromosome. It is used as a measure of the distance between genes and the relative position of a gene on a chromosome. It helps in the construction of a linkage map of a chromosome.