Rapid Gene Family Evolution of a Nematode Sperm Protein Despite Sequence Hyper-conservation

摘要: Reproductive proteins are often observed to be the most rapidly evolving elements within eukaryotic genomes. The major sperm protein (MSP) is unique phylum Nematoda and required for proper locomotion fertilization. Here, we annotate MSP gene family analyze their molecular evolution in 10 representative species across Nematoda. We show that MSPs hyper-conserved phylum, having maintained an amino acid sequence identity of 83.5-97.7% over 500 million years. This extremely slow rate makes some highly conserved genes yet identified. However, at level, hyper-variability both copy number genomic position species, suggesting rapid, lineage-specific evolution. Additionally, find evidence extensive conversion contributes maintenance chromosome-level clusters genes. Thus, while not conforming standard expectation reproductive proteins, our analysis nonetheless consistent with widely repeatable observation evolve rapidly, this case terms properties structure, number, organization. unusual evolutionary pattern likely generated by strong pleiotropic constraints acting on these balanced against expansion level whole family.