Characterising Mitochondrial Capture in an Iberian Shrew

Area of Science:

• Evolutionary Biology
• Biogeography
• Genetics

Background:

• Mitochondrial introgression can obscure species boundaries and influence evolutionary trajectories.
• Previous studies on the Sorex araneus complex suggested mitonuclear discordance in Iberian shrews due to hybridization.

Purpose of the Study:

• To investigate the extent and implications of mitochondrial introgression in Iberian shrew species.
• To clarify the phylogenetic relationships and hybridization events within the Sorex araneus/coronatus/granarius complex.

Main Methods:

• Genetic typing of 61 Sorex specimens from Portugal, Spain, France, and Andorra.
• Analysis of mitochondrial, autosomal, and sex-linked genetic loci.
• Integration of new data with previously published sequences.

Main Results:

• Confirmed Sorex coronatus and Sorex granarius as closely related species.
• Identified mitochondrial genome capture in Sorex granarius from Sorex araneus in the Central System, Spain.
• Evidence for recent hybridization and introgression among Sorex araneus, S. coronatus, and S. granarius.

Conclusions:

• Mitochondrial capture event in Sorex granarius explained by a biogeographical scenario involving Younger Dryas contact.
• Potential role of natural selection in favoring introgressed mitochondrial genomes in Sorex granarius.
• Ongoing hybridization and introgression among these shrew species continue to shape their genetic landscape.