In one type of ascus,two of the ascospores are genotypically like one of the parents and two are like the other parent.An ascus with this pattern is called a:
A) Parental ditype ascus
B) Nonparental ditype ascus
C) Original phenotype ascus
D) Recombinant phenotype ascus
E) None of these

Question

Quizplus · Accepted Answer

In a parental ditype ascus, two of the ascospores have the same genotype as one of the parental strains, and the other two ascospores have the same genotype as the other parental strain. This is because there has been no recombination between the two parental alleles during meiosis. This type of ascus is also called a PD (parental ditype) tetrad. Option B) Nonparental ditype ascus is incorrect because in this case, all four ascospores have a genotype different from that of the parents as a result of crossing over during meiosis. Options C) Original phenotype ascus and D) Recombinant phenotype ascus are not correct because they are not commonly used terms in describing tetrad analysis.

In One Type of Ascus,two of the Ascospores Are Genotypically