Reticulate evolution in terrestrial snails of Euhadra peliomphala species complex

Area of Science:

• Evolutionary Biology
• Genetics
• Malacology

Background:

• Introgression is increasingly recognized as a significant evolutionary force.
• Conclusive evidence for introgression has been scarce in many taxa, including Mollusca.
• The Euhadra peliomphala species complex offers a model for studying introgression in terrestrial snails.

Purpose of the Study:

• To investigate the genetic structure and evolutionary history of the Euhadra peliomphala species complex.
• To identify and characterize instances of introgression within this species complex.
• To explore the factors contributing to introgression events.

Main Methods:

• Genome-wide single nucleotide polymorphisms (SNPs) were obtained using double digest restriction site-associated DNA sequencing.
• Population genetic analysis was employed to determine genetic structure.
• Phylogenetic network reconstruction was used to detect reticulate evolution and introgression events.

Main Results:

• The study identified 12 distinct, parapatrically distributed lineages within the E. peliomphala species complex.
• Hybrid zones were detected between several lineage pairs.
• Three reticulate events, including introgression from an extinct lineage and human-induced introgression, were identified.

Conclusions:

• The Euhadra peliomphala species complex exhibits a highly reticulated evolutionary history.
• This research provides robust evidence of introgression in terrestrial snails.
• The findings establish a foundation for future studies on introgression-driven evolution in this group.