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Gene loci A, B, H and Q are in the same linkage group but not necessarily in that order. Test crosses were done with each cross involving two of the gene loci. A percent recombination was obtained for each pair of gene loci.
What is the order of the loci?
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Correct Answer: C. A, H, Q, B
Genetic linkage relates the tendency of genes located close to each other on a chromosome to be inherited together during meiosis. Genes whose positions (= loci) are nearer to each other are less likely to be separated onto different chromatids during chromosomal crossover, and are thus genetically linked.
If there is very little recombination (see Q and H in the table) then those loci must be very, very close to each other. If the percent recombination is high, it suggests that the loci are further apart and that’s why they assort independently more often. In other words, the percent recombination underlines how far away loci are on the gene map.
A -> 16 -> B
A -> 10 -> Q -> 6 -> B
A -> 5 -> H -> 5 -> Q -> 6 -> B
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