Genetic changes and evolutionary analysis of canine circovirus

Area of Science:

• Veterinary Virology
• Molecular Evolution
• Genomics

Background:

• Canine circovirus (canineCV) is linked to severe canine diseases like vasculitis and hemorrhagic enteritis.
• The virus exhibits global distribution and ongoing evolution through recombination and mutation.
• Key aspects of canineCV, including its origin and host adaptation, require further investigation.

Purpose of the Study:

• To investigate the evolutionary origin of canineCV.
• To analyze codon usage patterns and host adaptation of canineCV.
• To understand the factors driving canineCV evolution and host specificity.

Main Methods:

• Phylogenetic analysis (MCC, ML trees) and Principal Component Analysis (PCA) of 93 canineCV coding sequences.
• Analysis of nucleotide biases, codon usage bias (ENC), and codon adaptation indices (CAI, RCDI, SiD).
• Correlation, ENC plot, and neutrality plot analyses to determine codon usage shaping forces.

Main Results:

• CanineCV sequences were classified into five distinct genotypes.
• Phylogenetic analysis suggests an origin from bat circovirus.
• Codon usage is primarily shaped by natural selection, with better adaptation observed in red foxes (Vulpes vulpes) than domestic dogs (Canis familiaris).

Conclusions:

• A hypothesis of cross-species transmission from bats to canids, including dogs, wolves, and foxes, was proposed.
• Natural selection significantly influences canineCV codon usage patterns.
• CanineCV demonstrates differential host adaptation, favoring certain canid species over others.