Multiple Choice
During which phase of meiosis could an error result in trisomy, and what is the mechanism by which this occurs?
2
views
9. Mitosis and Meiosis
Meiosis
Struggling with Genetics?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
During meiosis I, can nondisjunction (failure of homologous chromosomes to separate) occur, and what is the consequence if it does?
A
No, nondisjunction can only occur during meiosis II.
B
No, homologous chromosomes always separate correctly in meiosis I.
C
Yes, but it only affects the number of chromatids, not chromosomes, in the gametes.
D
Yes, nondisjunction can occur in meiosis I, leading to gametes with an abnormal number of chromosomes.
Verified step by step guidance1
Understand the process of meiosis I: during this stage, homologous chromosomes are supposed to separate and move to opposite poles of the cell.
Define nondisjunction: it is the failure of homologous chromosomes (in meiosis I) or sister chromatids (in meiosis II) to separate properly.
Recognize that nondisjunction can indeed occur during meiosis I, which means both homologous chromosomes go to the same daughter cell instead of separating.
Analyze the consequence: because homologous chromosomes fail to separate, the resulting gametes will have an abnormal number of chromosomes—some will have an extra chromosome (n+1) and some will be missing one (n-1).
Conclude that this abnormal chromosome number in gametes can lead to disorders caused by aneuploidy if such gametes participate in fertilization.
Related Videos
Related Practice
