Question

Inversions are said to "suppress crossing over." Is this ter. minology technically correct? If not, restate the description accurately.

Short answer

Answer: Inversions can reduce or prevent crossing over in the affected chromosomal regions.

Step-by-step solution

Understanding Inversions

Inversions are chromosomal mutations in which a segment of a chromosome is reversed end to end. An inversion occurs when a chromosome breaks in two places and the resulting piece of the chromosome is reinserted in the opposite orientation.

Understanding Crossing Over

Crossing over is a process that occurs during meiosis, where homologous chromosomes (two chromosomes having the same genes at the same loci but can have different alleles) exchange segments by breaking and rejoining each other. It results in a recombinant chromosome with a different combination of alleles than the parent chromosomes. Crossing over increases genetic diversity within a population.

The Impact of Inversions on Crossing Over

When an inversion occurs in one of the homologous chromosomes, the corresponding segments may not align properly during meiosis. As a result, the exchange of genetic material through crossover becomes difficult, if not impossible, because the break points required for exchange do not match. In other words, the inversion suppresses crossing over.

Evaluating the Terminology

While the term "Inversions suppress crossing over" is generally understandable, it may not be technically precise. A more accurate description could be: "Inversions can reduce or prevent crossing over in the affected chromosomal regions." This description acknowledges that inversions can have varying degrees of impact on crossing over, rather than suggesting that they always completely suppress it. Additionally, it clarifies that the suppression of crossing over is specific to the affected regions of chromosomes and not a complete suppression across all regions.