Historical biogeography and interspecific mtDNA introgression in Euhadra peliomphala (the Japanese land snail)

Abstract

We assess variation in mitochondrial DNA (mtDNA) using partial sequences (560 bp) of the COI gene among populations of Japanese land snails, Euhadra peliomphala. Phylogeographical analysis reveals ®ve primary clades that correspond basically to ®ve discrete areas: the Boso Peninsula (B), the Kanto area (K), around Lake Ashinoko (A), the Northern Izu Peninsula (N), and the Southern Izu Peninsula (S). Although there are no current geographical barriers separating these ®ve subpopulations, the borders between each area correspond to palaeogeographical events during the Pleistocene, such as volcanic activities and the disappearance of the landbridge between the Southern Boso area and the mainland of Japan. In addition, our analysis of isolation-by-distance and the distribution of pairwise sequence dierences indicate that haplotypes of the B and K lineages have recently increased their population size exponentially. We have also discovered interspeci®c mtDNA introgression between E. peliomphala and the parapatric species E. brandtii at the contact zone in the Northern Kanto area. Unexpectedly, the E. brandtii-type mtDNA was also found in the populations of E. peliomphala in the Southern Boso area. Because recent contact between both species is unlikely, the introgressed mtDNA of E. brandtii could be a remnant of past hybridization, when E. peliomphala colonized this area via the landbridge that existed in the early Pleistocene.

Molecular Phylogenetic Relationships of Flightless Beetles Belonging to the GenusMesechthistatusBreuning, (Coleoptera: Cerambycidae) Inferred from Mitochondrial COI Gene Sequences.

“…However, morphological characteristics and the fact that the location of collection was within that of the M. furciferus distribution area imply that M. furciferus (FUR 28) should be included in linage A. As a specimen of M. furciferus was collected in the vicinity of the M. binodosus distributional boundary, it is likely that introgressive hybridization (e. g. Nagata et al 2007; Shimizu and Ueshima 2000; Sota et al 2001) took place from M. binodosus to M. furciferus sometime in the past, thus giving “FUR 28” the M. binodosus haplotype. Given that the “FUR 27” that was collected at the same location as “FUR 28” has the same COI haplotype as M. furciferus , it is likely that individuals that underwent introgressive hybridization now exist together as a single group in one location.…”

Phylogeography of the land snail genus Orcula(Orculidae, Stylommatophora) with emphasis on the Eastern Alpine taxa: speciation, hybridization and morphological variation

“…[31]. In land snail species, incomplete lineage is discussed in species of the hygromiid genus Xerocrassa Monterosato, 1892 [32] and the helicid Cornu aspersum [33], whereas mt introgression is assumed to have happened in other Xerocrassa species [31] and in the camaenid genus Euhadra Pilsbry, 1890 [34]. …”

Mitochondrial and nuclear DNA analysis revealed a cryptic species and genetic introgression in Littorina sitkana (Mollusca, Gastropoda)

“…The exceptional associations between HSC70 and mtDNA haplotypes (7% of genotyped samples from Hokkaido had CBb ? HSCa, see Table 3) can probably be attributed to genetic introgression of mitochondrial DNA caused by occasional hybridization after separation between L. sitkana and CladeB, as observed in many other species (e.g., Lamb and Avise 1986;Mikhailova et al 2009;Reid et al 2006;Shimizu and Ueshima 2000;Yamazaki et al 2008;Wiwegweaw et al 2009). Nevertheless, such hybridization events found in the present study are unlikely to have occurred recently because no HSCa and HSCb heterozygotes were observed in our investigation.…”