Evolution of cd59 gene in mammals

Area of Science:

• Evolutionary biology
• Molecular biology
• Genomics

Background:

• CD59 is a crucial complement regulatory protein.
• Understanding its evolutionary trajectory provides insights into immune system adaptation.
• Mammalian CD59 evolution is not fully characterized.

Purpose of the Study:

• To investigate the evolutionary pressures on the CD59 gene across mammals.
• To identify specific sites under positive or negative selection.
• To explore the impact of gene duplication on CD59 evolution.

Main Methods:

• Obtained CD59-coding sequences from five mammalian species.
• Utilized PCR and BLAST for sequence acquisition.
• Analyzed nucleotide substitution rates using synonymous and nonsynonymous comparisons.
• Applied site-specific and branch-site-specific models in PAML software.

Main Results:

• Mammalian CD59 generally experienced negative evolutionary selection.
• Four specific sites under positive selection were identified on the molecular surface, with two in key functional domains.
• One site in the cd59a and cd59b lineages showed accelerated evolution due to positive selection post-gene duplication in mice.

Conclusions:

• CD59 evolution is shaped by both purifying and positive selection.
• Positive selection at specific sites may indicate adaptation or functional diversification.
• Gene duplication events, like in mice, can lead to accelerated evolution of CD59 paralogs.