Question

A cell undergoing meiosis experiences a problem with its microtubules, such that proper separation of the paired chromosomes carrying alleles Q and q does not occur during anaphase I. What is the most likely effect on the four daughter cells?

a.) All four daughter cells will have a full chromosome set except two daughter cells will have one extra chromosome that contains the Q or q allele, and the other two daughter cells will be missing the chromosome that contains the Q or q allele.
b.) All four daughter cells will have a full chromosome set except one daughter cell will have two extra chromosomes containing the Q allele, one daughter cell will have two extra chromosomes containing the q allele, and the other two daughter cells will only have one chromosome containing the Q or q allele.
c.) All daughter cells will have a full set of chromosomes, minus copies of the Q and q alleles in each daughter cell.
d.) All daughter cells will have full sets of chromosomes, including the Q and q alleles in each daughter cell.

Answer 1

Nondisjunction during meiosis I, where homologous chromosomes fail to separate, often results in two daughter cells with an extra chromosome and two daughter cells missing a chromosome, specifically affecting the distribution of alleles Q and q.

Step-by-step explanation:

If a cell undergoing meiosis experiences a problem with its microtubules, such that proper separation of the paired chromosomes carrying alleles Q and q does not occur during anaphase I, the most likely effect on the four daughter cells would be that all four daughter cells will have a full chromosome set except two daughter cells will have one extra chromosome that contains the Q or q allele, and the other two daughter cells will be missing the chromosome that contains the Q or q allele. This phenomenon is known as nondisjunction, where homologous chromosomes or sister chromatids fail to separate during meiosis, resulting in an abnormal chromosome number. Specifically, if nondisjunction occurs in meiosis I, the pair of homologous chromosomes do not separate, leading to two of the gametes having an extra chromosome (n + 1) and two gametes missing a chromosome (n - 1).