Humans have 23 pairs of chromosomes.By contrast,chimpanzees have 24 pairs of chromosomes and lack any pair resembling the long human chromosome 2 pair;instead,chimpanzees have two pairs of medium-sized chromosomes,each of which resembles parts of human chromosome pair 2.What is the most likely explanation for these differences and similarities in the human and chimpanzee genomes?

Question

Quizplus · Accepted Answer

The most widely accepted explanation is that the common ancestor of humans and chimpanzees had 24 pairs of chromosomes, and in the human lineage, two chromosomes fused end to end, resulting in the formation of human chromosome pair 2. This fusion likely provided a selective advantage, allowing human ancestors to evolve new traits and adaptations. The presence of two pairs of medium-sized chromosomes in chimpanzees that resemble parts of human chromosome pair 2 supports this theory.

Humans Have 23 Pairs of Chromosomes