Complete mitochondrial phylogeny of palaearctic serotine bats (Genus eptesicus, vespertilionidae, chiroptera)

Abstract

Investigating speciation mechanisms is essential in evolutionary biology studies to understand biodiversity on Earth. As bats are one of the least studied groups of mammals, understanding their taxonomy for designing effective conservation strategies is important. The Serotine bats, which have over 30 species, provide a rich study group due to their wide distribution in various habitats such as forests, urban areas, deserts, and caves. With their insectivorous diet, they play an important role in the population control of insects and thus maintaining ecological balance. The complex evolution of Serotine bats is shaped by geography, environmental changes, and gene flow, providing further research opportunities. Phylogenetic studies conducted on mitochondrial and nuclear genes showed discordance between mitochondrial and nuclear phylogenies. Species identification among Serotine bats is often challenged by introgression events. This study aims to assemble and analyze complete mitochondrial genomes of Palaearctic Serotine bats to understand their phylogenetic relationships and detect possible selection signatures within their mitochondrial genomes. Thirteen samples representing seven species and nine subspecies were assembled, and all 37 mitochondrial genes are annotated. The phylogenetic relationships are inferred using Bayesian and Maximum Likelihood methods. The selection pressure on thirteen protein genes is investigated by calculating DNA polymorphism for each gene and constructing a Bayesian phylogenetic tree. The resulting tree topologies are compared with whole mitochondrial genome phylogeny topologies. On the assembled mitogenomes, all 37 mitochondrial genes, including thirteen protein-coding genes, twenty-two transfer RNAs, two ribosomal RNAs, and one non-coding displacement loop (D-loop), were identified. The resulting analysis shows two main mitochondrial phylogenetic groups: Eastern serotinus-bottae and Western serotinus-nilssonii in the Palaearctic Serotine bats. This result validates previously determined species groups. The selection analysis shows differences in topologies in ND2, ND4L, ND6, and COX3 trees; however, DNA polymorphism statistics fail to validate the analyzed pattern which indicates that the mitochondrial genes might not have a selection among Palaearctic Serotine bat species.