Question

Which of the following is true about chromosome inversions?

a) They are always deleterious
b) They always reduce fitness
c) They break apart linkage groups
d) They are rare in fruit flies

Answer 1

Chromosome inversions are structural rearrangements that change the orientation of genes without loss or gain of genetic material. They can result in functional changes due to altered gene position. Inversions can be pericentric or paracentric and have more mild effects compared to aneuploidies.

Step-by-step explanation:

Chromosome inversions are structural rearrangements in chromosomes where a segment detaches, rotates 180°, and reinserts into the chromosome. Inversions usually do not result in the loss or gain of genetic material, unless the breakpoints occur within genes. However, inversions can change the orientation of genes, which can lead to functional changes by altering the position of gene regulators, resulting in aberrant levels of gene products.

An inversion can be pericentric if it includes the centromere, or paracentric if it occurs outside the centromere. Pericentric inversions can change the relative lengths of chromosome arms, making them easily identifiable.

Inversions are not always deleterious or reduce fitness. While they can cause problems during reproduction and lead to infertility, inversions often have more mild effects than other chromosomal abnormalities like aneuploidies.