Interspecific hybridization between Mauremys reevesii and Mauremys sinensis: Evidence from morphology and DNA sequence data

Abstract

Turtle hybrids have been found in some taxa, but so far, studies on interspecific hybridization between Mauremy reevesii and Mauremy sinensis have not been reported. Recently, we obtained three specimens (Hy1, Hy2, Hy3）with unusual morphological characteristics from pet trade Market, which are suspected to be hybrids rather than new species, because they were morphologies intermediate between M. reevesii and M. sinensis. In further study, we analyzed two aspects; morphological characteristics and molecular data, separately. The morphological characteristics showed that the pattern of the carapace, the plastron and neck stripes of the three specimens was between that of M. reevesii and M. sinensis (the morphological features of Hy1 and Hy2 have more resemblance with those of M. sinensis, and those of Hy3 have more resemblance with those of M. reevesii). In molecular analyses, two mitochondrial genes (12S, cytb) and two nuclear genes (RAG-1, R35) were respectively cloned from each suspected specimen. One sequence was obtained for each mitochondrial gene, while two different sequences were obtained for each nuclear gene. Phylogenetic analyses revealed that mitochondrial genes sequences from each suspected specimen clustered into the corresponding sequences of their putative female parents, while the two pairs nuclear parental alleles sequences were strongly paraphyletic, for they were included in two different genetic lineages (M. reevesii and M. sinensis). Therefore, we concluded that the three suspected specimens are hybrids (Hy1 and Hy2: M. reevesii♂ × M. sinensis♀; Hy3: M. sinensis♂ × M. reevesii♀). It is the first report that interspecies hybridization of M. reevesii and M. sinensis can cross completely.

Key words: Mauremys reevesii, Mauremys sinensis, hybridization, morphology, DNA sequence.