Two strains of S.cerevisae (yeast)are crossed.One has the genotype A B and the other a b.Which statement correctly describes the tetrads that can be produced by one reciprocal exchange without gene conversion in the dihybrid?
A)Recombination occurs at the four-strand stage to produce a tetrad with A B, A B, a B, and a b chromosomes.
B)Recombination occurs at the four-strand stage to produce a tetrad with A B, A b, a B, and a b chromosomes.
C)Recombination occurs at the two-strand stage to produce a tetrad with A B, A b, a B, and a b chromosomes.
D)Recombination occurs at the two-strand stage to produce a tetrad with A b, A b, a B, and a B chromosomes.

Question

Quizplus · Accepted Answer

Recombination in S. cerevisiae occurs at the four-strand stage of meiosis, leading to the production of tetrads that can contain recombinant and non-recombinant chromosomes. A single reciprocal exchange between the A B and a b chromosomes without gene conversion would result in one tetrad containing all four possible combinations of the alleles: A B, A b, a B, and a b.

Two Strains of S