Question

individual organisms with 27 chromosomes are _____ and are more likely to be sterile because there are ______at meiosis I that cause a relatively high number of unbalanced gametes to be formed.

Answer 1

Individuals with 27 chromosomes are aneuploid and likely sterile due to irregular chromosome pairings at meiosis I, leading to unbalanced gametes. These genetic irregularities disrupt normal meiotic processes and often result in reproductive sterility.

Step-by-step explanation:

Individual organisms with 27 chromosomes are aneuploid and are more likely to be sterile because there are irregular pairings at meiosis I that cause a relatively high number of unbalanced gametes to be formed. An odd number of chromosomes leads to difficulties during the pairing of chromosomes, which is crucial for a successful meiosis. This condition can result from errors such as nondisjunction, where chromosomes fail to separate properly during cell division, resulting in gametes with an abnormal number of chromosomes (referred to as aneuploidy).

During meiosis, the random orientation of homologous chromosomes at metaphase I contributes to genetic diversity. However, in individuals with an odd number of chromosomes, such as 27, this process is disrupted because one chromosome lacks a homologous partner to pair with. This can lead to gametes with missing or extra chromosomes which can ultimately render the organism sterile. For example, in humans, having 2n+1 (trisomy) or 2n-1 (monosomy) chromosomes affects the individual's viability or fertility. Examples include Down Syndrome, which is characterized by an extra copy of chromosome 21 (trisomy 21).