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Consider two genes in the northern flying squirrel (Glaucomys sabrinus): at the first locus, the allele for gray fur (G) is dominant to brown fur (g). At the second locus, the allele for long whiskers (L) is dominant to the allele for short whiskers (l).

A true breeding gray-furred, long-whiskered squirrel is crossed with a true-breeding brown-furred, short-whiskered squirrel, producing a heterozygous F1 with cis arrangement for the alleles of the two genes.

If the F1 heterozygote is test-crossed with a completely recessive brown-furred, short-whiskered flying squirrel, how many map units apart would the two loci be if the following offspring numbers were observed?

Trait Offspring Number
Gray fur, long whiskers 35
Gray fur, short whiskers 15
Brown fur, long whiskers 15
Brown fur, short whiskers 35

35 map units


15 map units


30 map units


70 map units


7.5 map units


Not enough information is given to determine the map distance between the two loci.

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