Here I present: “Great Ape & Human Synteny: Mouse Synteny”.
PRELUDE.
Humans have a characteristic chromosomes 1-22, XY while great ape species—chimpanzees, gorillas, and orangutans—have chromosomes 1-22, XY with the second chromosome separated as 2A and 2B.
INTRODUCTION.
Chromosome Number:
The primary difference is the number of chromosomes.
The human lineage experienced a telomeric fusion of two smaller ancestral ape-like chromosomes to form what is now human chromosome 2.
This event reduced the chromosome number by two.
Banding Patterns:
When stained using a process called G-banding (as seen in the provided image of a human karyotype ABOVE), the banding patterns of human chromosomes show remarkable similarities to corresponding ape chromosomes BELOW.
Specifically, the banding pattern of the large human chromosome 2 closely matches two separate, smaller chromosomes (known as 2A and 2B) found in apes.
Structural Rearrangements:
Beyond the fusion event, humans and apes also differ by several large-scale structural changes, including pericentric inversions (where a segment of a chromosome is reversed end-to-end around the centromere) on specific chromosomes, such as human chromosomes’ 1 and 18.
DNA Similarity:
Despite these visible chromosomal differences, humans and chimpanzees share about 98% of their DNA sequence, with gorillas being slightly less similar at about 98.3%, and orangutans even less so.
Human-mouse synteny is shown BENEATH. In contrast to primate, murine (mice) are distant in evolution from humans.. However, the laboratory research the mouse genome is of great value.
