In corn the recessive alleles v virescent seedlings pr red a

In corn, the recessive alleles v (virescent seedlings), pr (red aleurone), and bm (brown midrib) are all encoded by genes on chromosome 5, but not necessarily in the order given. The following progeny are obtained from a cross between a fully heterozygous corn plant and a corn plant having virescent seedlings, red aleurone, and brown midribs:

a. List the parental and double cross over genotypes.

b. What is the gene order?

c. Provide a genetic map of the three loci, including the distances in map units between the gene pairs.

d. Calculate the coefficient of coincidence (C) and the interference (I).

Solution

v--------------------pr-----------------bm

<------22.2-----------------43.3-------->

the difference is due to rare double hybrids.............228+207+525+543+2(108+123)/3000x100=65.5