Primate evolution of the recombination regulator PRDM9.

Area of Science:

• Genetics and Evolutionary Biology
• Molecular Biology
• Primate Genomics

Background:

• The PRDM9 gene is crucial for meiosis, influencing recombination hotspots.
• Its zinc finger (ZF) DNA-binding domain is highly variable and key to its function.

Purpose of the Study:

• To investigate the evolutionary diversity of the PRDM9 ZF domain in primates.
• To understand the selective pressures and evolutionary history of PRDM9.

Main Methods:

• Sequencing the PRDM9 ZF domain in 64 primates across 18 species.
• Analyzing sequence diversity, positive selection, and phylogenetic relationships.
• Comparing primate PRDM9 alleles with archaic hominin sequences (Neandertal, Denisovan).

Main Results:

• Discovered 68 unique PRDM9 ZF alleles across the surveyed primate species.
• Identified widespread positive selection on DNA-contact residues and ZF expansion within clades.
• Archaic hominin PRDM9 alleles appear closely related to rare, African-specific human alleles.

Conclusions:

• The PRDM9 ZF domain shows rapid evolution and diversification across the primate lineage.
• PRDM9 variation may have played a role in primate speciation events.
• Understanding PRDM9 evolution offers insights into reproductive isolation and speciation.