Identification of two mitochondrial lineages in the large-scale loach (Paramisgurnus dabryanus) using cyt b–RFLP: evidence for nuclear genome similarity

Abstract

The large-scale loach Paramisgurnus dabryanus , introduced from continental Asia, coexists with the native dojo loach Misgurnus anguillicaudatus in Japan, likely causing genetic contamination of native populations through hybridization. Previous mitochondrial DNA (mtDNA) analyses have identified two divergent lineages of large-scale loach (groups 1 and 2), whereas nuclear DNA analysis of the RAG1 region revealed no differences between these two groups. In this study, we developed a novel mtDNA polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method targeting the cytochrome b region using Avr II and Nco I for rapid identification of groups 1 and 2 based on distinct fragment profiles. Consistent with previous research findings, nuclear DNA marker analyses revealed no differences between groups 1 and 2. This new marker enables efficient screening of large-scale loach lineages, facilitates distribution surveys, and clarifies the introduction pathways of this species.

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