Pale - 648 - Parental
Pale, oval - 64 - Single recombinant (recombination between T and R)
Pale, short - 10 - Double recombinant
Pale, oval, short - 102 - Single recombinant (recombination between T and L )
Oval - 6 - Double recombinant
Oval, Short - 618 - Parental
Short - 84 - Single recombinant (recombination between T and R)
Wild type - 98 - Single recombinant (recombination between T and L )
Total 1630
A). From the given table, the genotype of the parents is lTR and Ltr. Double cross over gave rise to the offspring with the phenotypes oval and plale, short. Thus, the gene order is L-T-R.
B). The recombination fraction between T and L pair of genes. = number of gametes produced by single crossover of T and L + number of double crossover gametes*100/ total number of gametes.
= [(102+98) + (10+6)]* 100/ 1630 = 13.25 map units.
The genetic distance between genes T and L = 13.25 map units.
C). The recombination fraction between T and R pair of genes. = number of gametes produced by single crossover of T and R + number of double crossover gametes*100/ total number of gametes.
= [(64+84) + (10+6)]* 100/ 1630 = 10.06 map units.
The genetic distance between genes T and R = 10.06 map units.
