Practice question

Canonical meiosis predicts 2:2 segregation within tetrad for heterozygous marker reflecting equal replication of alleles. Appearance aberrant ratios 3:1 or 1:3 and even more extreme 4:0 or 0:4 signifies gene conversion where heteroduplex DNA formed during recombination repaired nonreciprocally, replacing one allele with other via mismatch repair bias. Conversion tract copying during homologous recombination intermediate repair converts markers asymmetrically, producing excess one parental allele over other. Detection possible only when all four chromatid products recovered together, providing molecular evidence recombination and repair mechanisms operating during meiosis.