Comparative genome analysis of six malarial parasites using codon usage bias based tools

Area of Science:

• Genomics
• Molecular Biology
• Parasitology

Background:

• Codon usage bias (CUB) is a widespread phenomenon in organisms.
• Previous studies on Plasmodium CUB used limited datasets.
• This study provides a comprehensive comparative genomic analysis of CUB in six Plasmodium species.

Purpose of the Study:

• To analyze codon usage bias, amino acid frequency, effective number of codons, and optimal codons in six Plasmodium species.
• To investigate the factors driving differential codon usage patterns.
• To compare CUB across different Plasmodium species, including human, simian, and rodent parasites.

Main Methods:

• Comparative whole-genome analysis of six Plasmodium species.
• Analysis of codon usage bias (CUB).
• Assessment of compositional variation in amino acid frequency, effective number of codons, and optimal codons.
• Principal Component Analysis (PCA) for detailed comparison.

Main Results:

• Differential codon usage patterns in Plasmodium species arise from a combination of mutational and translational selection pressures.
• P.falciparum shows increased usage of A/T-ending codons due to composition bias and G/C at the third codon position due to translational selection.
• P.vivax codon usage is influenced by translational selection and composition bias; rodent parasites (P.berghei, P.chabaudii, P.yoelli) exhibit CUB similar to P.falciparum.
• P.knowlesi shows CUB variations similar to P.vivax, with distinct differences confirmed by PCA.

Conclusions:

• Mutational and translational selection pressures significantly influence codon usage bias across Plasmodium species.
• Distinct CUB patterns exist between human/simian and rodent Plasmodium parasites.
• Whole-genome analysis provides novel insights into the evolutionary forces shaping codon usage in malaria parasites.