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Pseudogenization of testis-specific Lfg5 predates human/Neanderthal divergence.
Marco Mariotti1, Temple F Smith2, Peter H Sudmant3
1Center for Genomic Regulation, Barcelona, Spain.
Journal of Human Genetics
|March 7, 2014
Summary
The Lifeguard family gene 5 (Lfg5) is a pseudogene in modern humans, Neanderthals, and Denisovans due to a premature stop codon. This inactivation, likely driven by selection, impacts human evolution and male fertility.
Area of Science:
- Genetics
- Evolutionary Biology
- Reproductive Biology
Background:
- Apoptosis plays a critical role in human spermatogenesis and infertility.
- The FasL-induced caspase cascade is a key pathway in apoptosis.
Purpose of the Study:
- To investigate the pseudogene status of the Lifeguard family gene 5 (Lfg5) in modern humans, Neanderthals, and Denisovans.
- To analyze the evolutionary context and potential selective pressures on Lfg5 inactivation.
Main Methods:
- Comparative genomics analysis of Lfg5 across hominin species and mammals.
- Phylogenetic analysis to understand gene conservation and changes.
- Identification of genetic mutations, specifically premature stop codons.
Main Results:
- The Lfg5 gene is a pseudogene in modern humans, Neanderthals, and Denisovans, characterized by a premature stop codon in exon 8.
- This pseudogenization event is unique among orthologs, with exceptions in domesticated bovines.
- Lfg5 expression is predominantly testis-specific in mammals.
Conclusions:
- The inactivation of Lfg5 in recent human evolution was likely a result of positive selection.
- Pseudogenization of Lfg5 may have implications for human male fertility and reproductive success.
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