Research Article: Mitochondrial and nuclear DNA reveals reticulate evolution in hares (Lepus spp., Lagomorpha, Mammalia) from Ethiopia

Date Published: August 2, 2017

Publisher: Public Library of Science

Author(s): Zelalem Tolesa, Endashaw Bekele, Kassahun Tesfaye, Hichem Ben Slimen, Juan Valqui, Abebe Getahun, Günther B. Hartl, Franz Suchentrunk, Tzen-Yuh Chiang.

http://doi.org/10.1371/journal.pone.0180137

Abstract

For hares (Lepus spp., Leporidae, Lagomorpha, Mammalia) from Ethiopia no conclusive molecular phylogenetic data are available. To provide a first molecular phylogenetic model for the Abyssinian Hare (Lepus habessinicus), the Ethiopian Hare (L. fagani), and the Ethiopian Highland Hare (L. starcki) and their evolutionary relationships to hares from Africa, Eurasia, and North America, we phylogenetically analysed mitochondrial ATPase subunit 6 (ATP6; n = 153 / 416bp) and nuclear transferrin (TF; n = 155 / 434bp) sequences of phenotypically determined individuals. For the hares from Ethiopia, genotype composition at twelve microsatellite loci (n = 107) was used to explore both interspecific gene pool separation and levels of current hybridization, as has been observed in some other Lepus species. For phylogenetic analyses ATP6 and TF sequences of Lepus species from South and North Africa (L. capensis, L. saxatilis), the Anatolian peninsula and Europe (L. europaeus, L. timidus) were also produced and additional TF sequences of 18 Lepus species retrieved from GenBank were included as well. Median joining networks, neighbour joining, maximum likelihood analyses, as well as Bayesian inference resulted in similar models of evolution of the three species from Ethiopia for the ATP6 and TF sequences, respectively. The Ethiopian species are, however, not monophyletic, with signatures of contemporary uni- and bidirectional mitochondrial introgression and/ or shared ancestral polymorphism. Lepus habessinicus carries mtDNA distinct from South African L. capensis and North African L. capensis sensu lato; that finding is not in line with earlier suggestions of its conspecificity with L. capensis. Lepus starcki has mtDNA distinct from L. capensis and L. europaeus, which is not in line with earlier suggestions to include it either in L. capensis or L. europaeus. Lepus fagani shares mitochondrial haplotypes with the other two species from Ethiopia, despite its distinct phenotypic and microsatellite differences; moreover, it is not represented by a species-specific mitochondrial haplogroup, suggesting considerable mitochondrial capture by the other species from Ethiopia or species from other parts of Africa. Both mitochondrial and nuclear sequences indicate close phylogenetic relationships among all three Lepus species from Ethiopia, with L. fagani being surprisingly tightly connected to L. habessinicus. TF sequences suggest close evolutionary relationships between the three Ethiopian species and Cape hares from South and North Africa; they further suggest that hares from Ethiopia hold a position ancestral to many Eurasian and North American species.

Partial Text

Hares and jackrabbits (genus Lepus; Leporidae; order Lagomorpha; Mammalia) are a difficult group, systematically, due to their large intraspecific phenotypic variation, their wide phenotypic overlap among species (e.g., Angermann[1,2], Palacios[3,4], Flux and Angermann[5]; see also Suchentrunk et al. [6]), and their shallow evolutionary divergence with the possibility of reticulate evolution (e.g., Thulin et al.[7], Alves et al.[8], Liu et al.[9], Melo-Ferreira et al.[10,11]). Traditional taxonomy based on phenotypic and morphological characters has earlier led to the description of a bewildering number of forms, often given species or even genus ranks. Many earlier species descriptions, however, were based on limited numbers of specimens, characters with doubtful systematic meaning, or limited geographical sampling. This has led to many synonyms or unsecure taxa that are currently classified into around 30 species, depending on the underlying species concept, available chorological, phenotypic, morphological, and molecular data (e.g., Flux and Angermann[5], Hoffmann and Smith[12], Alves and Hackländer[13]). Nevertheless, the systematic status of a fair number of forms is still uncertain; several may prove conspecific or separate species, once meaningful and representative morphological, geographical, and molecular data are available.

 

Source:

http://doi.org/10.1371/journal.pone.0180137

 

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