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Home Q & A Board Biology-Related Homework Help Genetics and Developmental Biology
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rocketleague rocketleague
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6 years ago
A cross is made between yeast cells with different alleles for a set of linked genes: pr+q  p+rq+. The resulting tetrads show a 3:1 ratio for r+ to r instead of the expected 2:2 ratio. Can you explain how this could have occurred?
 
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6 years ago
Gene conversion by a mismatch repair mechanism could have caused this deviation from expected ratios. During pairing of homologous chromosomes in meiosis, recombination between the two inner chromatids occurred, resulting in heteroduplex (mismatched) DNA strands. Both mismatches were repaired by excision and DNA synthesis to match the parent DNA with the r+ allele.
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