The alleles for gene 1 are A and a The alleles for a second

The alleles for gene 1 are A and a. The alleles for a second gene are B and b. Crossing over between these two genes occurs 20% of the time. What is the corresponding recombination frequency? 10% 20% 30% 40% 50% What is the map distance between the two genes described in question 3? |10 m.u. 20 m u. 30 m u. 40 m u. 50 m.u.

Solution

3). b). 20%

During meiosis, each member of a pair of genes tends to be randomly distributed into gametes (receive alleles) independently of how other chromosomes are distributed. Genes that are having their loci nearer to each other are not generally separated during chromosomal crossover, and are inherited together to the offspring. These genes are known as linked genes (two different chromosomes), and they always have multiple alleles.

If two linked genes are separated by 10 cM (centi morgans or map units), the percent recombinants produced by this cross is always equal to the 10% and the remaining 90% will be identical to the parental genotype. Means, the percent crossing over is equal to the recombination frequency.