. A homozygous variety of maize with red leaves and normal seeds was crossed wit
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Question
. A homozygous variety of maize with red leaves and normal seeds was crossed with another homozygous variety with green leaves and tassel seeds (both recessive alleles). The F1 hybrids were then crossed to the green, tassel-seeded variety, and the following offspring were obtained: red, normal 124; red, tassel 126; green, normal 125; green, tassel 123.
a. What is the recombination frequency between these two genes?
b. Can you definitely say that the genes for plant color and seed type are linked or unlinked? Explain.
Explanation / Answer
Parents: RRSS and rrss
F1 would be RrSs.
The cross of RrSs x rrss would give the four classes of genotypes and phenotypes:
RrSs, rrSs, Rrss, rrss
This matches the data given in the question.
REcombination frequency is No. of recombinant progeny/Total progeny. The result is multiplied by 100.
Here we see the number of recombinants is 126 + 125 which is 251.
Total progeny is 498.
The RF is 251/498 which is 0.50. This is multiplied by 100 to get 50%.
This RF shows that these genes are not linked since a RF of 50 and above indicates that these genes separate independently
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