Multiple choice

In Neurospora, tetrad analysis revealed that the percentage of mycelia regarding different combination of alleles A, a, B and b was AB = 35%, Ab = 15%, aB = 14%, ab = 36%. It means that

  1. two genes show independent assortment

  2. two genes show incomplete linkage

  3. two genes show complete linkage

  4. two genes are located on different chromosomes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The tetrad analysis shows parental combinations (AB and ab) at 71% and recombinant combinations (Ab and aB) at 29%. This deviation from the 50:50 ratio expected for independent assortment indicates linkage, but the presence of 29% recombinants shows the linkage is incomplete (complete linkage would produce 0% recombinants). Therefore, the genes are linked but not completely so.

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