The most common error in meiosis occurs when homologous chromosomes fail to separate. What is this process called?

The most common error in meiosis occurs when homologous chromosomes fail to separate. What is this process called?

• A. Polyploidy
• B. Nondisjunction
• C. Trisomy
• D. DNA Profiling

Answer: (B)

Errors in chromosome separation during meiosis are being tested here. When homologous chromosomes fail to separate during meiosis I, both homologs move to the same gamete while the other gamete ends up with none. After fertilization, this creates an embryo with an abnormal number of chromosomes—an aneuploid state such as trisomy or monosomy. This failure to separate is called nondisjunction, and it’s the most common meiotic error that leads to such chromosomal imbalances. The other terms refer to different concepts: polyploidy means having extra complete sets of chromosomes, not a single pair failing to separate; trisomy describes the outcome (an extra chromosome), not the process; and DNA profiling is a method for analyzing DNA, unrelated to meiotic chromosome segregation.

Errors in chromosome separation during meiosis are being tested here. When homologous chromosomes fail to separate during meiosis I, both homologs move to the same gamete while the other gamete ends up with none. After fertilization, this creates an embryo with an abnormal number of chromosomes—an aneuploid state such as trisomy or monosomy. This failure to separate is called nondisjunction, and it’s the most common meiotic error that leads to such chromosomal imbalances. The other terms refer to different concepts: polyploidy means having extra complete sets of chromosomes, not a single pair failing to separate; trisomy describes the outcome (an extra chromosome), not the process; and DNA profiling is a method for analyzing DNA, unrelated to meiotic chromosome segregation.