In: Biology
In corn the alleles C and c result in colored versus colorless seeds, Wx and wx in nonwaxy versus waxy endosperm, and Sh and sh in plump versus shrunken endosperm. When plants grown from seeds heterozygous for each of these pairs of alleles were crossed with plants from colorless, waxy, shrunken seeds, the resulting seeds were:
colorless, waxy, plump 2672
colored, waxy, plump 104
colorless, nonwaxy, plump 595
colored, nonwaxy, plump 11
colored, waxy, shrunken 580
colorless, nonwaxy, shrunken 121
colorless, waxy, shrunken 7
colored, nonwaxy, shrunken 2702
Total 6792
Determine the order of and distances between these genes. Also calculate the coefficient of coincidence (C) and the interference (I)
Ans:
The genotypes which found most frequently are called parental genotypes. So, genotypes c Wx Sh and C wx sh are the parental genotypes. The genotypes which found less frequently is called double crossover phenotypes. So, genotypes C wx Sh and c Wx sh are the double crossover genotypes.
The order of three genes is c-sh-wx. The distance between gene c and sh is 3.58 map units (m.u.) and distance between gene sh and wx is 17.56 map units (m.u.).
The calculated coefficient of coincidence is 0.43
The calculated interference is 0.57
All the calculation are given below-