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Positive Selection in the Evolution of Mammalian CRISPs
Alberto Vicens1,2, Claudia L Treviño3
1Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico. avicens@uvigo.es.
Journal of Molecular Evolution
|October 30, 2018
Summary
Mammalian Cysteine-Rich Secretory Proteins (CRISPs) evolved adaptively, showing positive selection across the family. This molecular adaptation, particularly in reproductive roles, drives CRISP diversification and interspecific differences.
Area of Science:
- Evolutionary biology
- Molecular biology
- Reproductive biology
Background:
- Cysteine-Rich Secretory Proteins (CRISPs) are a versatile protein family with roles in reptilian venom and mammalian reproduction.
- Mammals typically express three CRISPs, highly abundant in male reproductive tissues like the testis and accessory organs.
Purpose of the Study:
- To investigate the molecular adaptation of mammalian CRISPs using phylogenetic methods.
- To test the hypothesis that mammalian CRISPs have undergone positive selection due to their roles in male reproduction and sexual selection.
Main Methods:
- Phylogenetic analysis of mammalian CRISP sequences.
- Identification of positive selection signatures across CRISP genes and functional domains.
Main Results:
- Evidence of positive selection was found in all mammalian CRISPs, with varying intensity among CRISP members (CRISP3 > CRISP1, CRISP2).
- Positive selection impacted functional domains differently, notably on Pathogenesis-Related 1 (PR-1) in CRISP2 and Ion Channel Regulator (ICR) in CRISP1 and CRISP3.
- A novel CRISP was identified in some rodents, suggesting gene duplication and neofunctionalization contribute to reproductive success.
Conclusions:
- Mammalian CRISP evolution is characterized by recurrent adaptive changes driven by positive selection.
- CRISP family diversification is shaped by gene duplication and neofunctionalization, leading to interspecific variations in function and activity.
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