Female animals heterozygous for three recessive alleles (a/a+, b/+ , and c/c+ ) are mated with normal males. The phenotypes of the F1 progeny are as follows:
females:
a+b+c+ 1991
males:
a+b+c+ 31
a+b+c 33
a+bc+ 443
a+bc 2
ab+c+ 1
ab+c 427
abc+ 25
abc 38
Explain the results. Show the genotypes of the parents, and construct a linkage map showing the correct order and distance of the loci.