Monomorphism of human cytochrome c

Area of Science:

• Biochemistry
• Genetics
• Evolutionary Biology

Background:

• Cytochrome c (Cyt c) is crucial for mitochondrial electron transport and apoptosis.
• A rapid amino acid replacement rate in primate Cyt c suggests evolutionary adaptation.
• Nonsynonymous single nucleotide polymorphisms (nsSNPs) in Cyt c could have significant functional impacts due to its critical cellular roles.

Purpose of the Study:

• To investigate the presence and functional consequences of nsSNPs in the human CYCS gene.
• To experimentally validate putative nsSNPs reported in the dbSNP database for human Cyt c.

Main Methods:

• Bioinformatic analysis of the dbSNP database for human Cyt c nsSNPs.
• Experimental validation using gene sequencing of Cyt c in a diverse human population panel (95 individuals).

Main Results:

• A large number of putative nsSNPs were identified in the dbSNP database.
• Experimental validation failed to confirm any of the putative nsSNPs in the analyzed human population.
• No non-rare allelic variants of the Cyt c protein were detected.

Conclusions:

• Human cytochrome c protein exhibits a lack of common allelic variants, suggesting strong functional conservation.
• The absence of nsSNPs indicates significant selective pressure maintaining the integrity of the Cyt c protein sequence.
• Findings contradict previous reports of rapid evolution in primate Cyt c, highlighting species-specific evolutionary constraints.