Genetic characterization of Callosciurus Asiatic squirrels introduced in Argentina

GABRIELLI M; Y CARDOSO; V BENITEZ; AC GOZZI; ML GUICHÓN; M LIZARRALDE

ITALIAN JOURNAL OF ZOOLOGY

TAYLOR & FRANCIS LTD

Año: 2014 vol. 81 p. 1 - 16

1125-0003

Squirrels have been traded in the pet market for several decades, and numerous species have established in the wild. TheAsiatic species Callosciurus erythraeus and Callosciurus finlaysonii have been introduced into other parts of Asia, in Europe andSouth America. In this study, (1) we conducted a genetic characterization of C. erythraeus introduced into Argentina andcompared them with native and introduced populations in Asia, and (2) we analyzed genetic variation among the four invasionfoci in Argentina in order to corroborate that the pathway of invasion was a single introduction event in the country andsubsequent translocations. We analyzed mitochondrial (cytochrome b, Cyt b; cytochrome oxidase c subunit I, COI andD-loop) and nuclear (recombination activating gene I, RAGI) DNA markers using the classical method (DNA barcoding gapanalysis) and also the Automatic Barcode Gap Discovery method (ABGD). The markers D-loop, COI, and RAG1 indicatedthat the introduced squirrels from the different invasion foci formed a monophyletic group that, together with only onehaplotype for the D-loop and COI markers, supported the hypothesis of one introduction event into Argentina followed bysubsequent translocations. Unexpectedly, sequences from squirrels captured in Argentina were more related to C. finlaysoniithan to C. erythraeus for D-loop and Cyt b markers. However, intraspecific variation among sequences of C. erythraeusbelonging to different subspecies or collected in different regions was large and comparable with the distance to the sequencesfrom Argentina. The ABGD method also indicated large genetic variability within C. erythraeus and close proximity betweensquirrels from Argentina and C. finlaysonii. The complex taxonomy of Callosciurus, as occurs with the sister species C. erythraeusand C. finlaysonii, requires a thorough systematic revision. A simultaneous analysis of diagnostic morphological characters andgenetic markers is needed and will provide new insight regarding the worldwide invasion of Asiatic squirrels.