Restriction fragment length polymorphism (RFLP) analysis of three nuclear genes in rock-wallabies (Petrogale: Marsupialia: Macropodidae): a search for genic markers to identify taxa within the Petrogale lateralis-penicillata group

Abstract

Many rock-wallaby (Petrogale) species within the lateralis–penicillata complex are morphologically similar and can be distinguished only by their unique karyotypes, frustrating attempts to identify specimens in the field and in museums. As chromosome preparations are not always obtainable from specimens, additional diagnostic molecular markers are required. In this study, restriction fragment length polymorphism (RFLP) analysis of three nuclear genes was undertaken using 100 Petrogale specimens, including representatives of 12 taxa. Eleven novel diagnostic nuclear DNA markers were identified, which enabled the identification of four taxa (P. penicillata, P. purpureicollis, P. lateralis and P. inornata). No markers were found that could reliably distinguish amongst five north-east Queensland species (P. assimilis, P. sharmani, P. mareeba, P. godmani and P. coenensis) or the sampled intraspecific taxa of P. lateralis (P. l . lateralis, P. l. pearsoni, MacDonnell Ranges race). These results are consistent with previous studies in demonstrating that P. penicillata, P. purpureicollis, P. lateralis and P. inornata are genically distinct and that the north-east Queensland species and subspecies/races of P. lateralis form two groups of very closely related taxa. Future research should target more rapidly evolving DNA regions, in order to identify specific molecular markers that distinguish amongst taxa within these two groups. Meanwhile, karyotypic analysis remains the only definitive technique currently available to unambiguously identify all taxa within the lateralis–penicillata group.

The identity of the Depuch Island rock-wallaby revealed through ancient DNA

“…Previous attempts to identify unknown taxa using traditional morphological criteria have sometimes been challenging when dealing with morphologically cryptic species such as Petrogale (Loupis and Eldridge 2001). Other researchers have shown that although karyotypes can be useful in differentiating rock-wallaby taxa (Eldridge et al 1991a), a major limitation is the necessity of living tissue that can then be cultured (Eldridge and Spencer 1997).…”

“…Prior to DNA studies one of the most convincing genetic species determiners had been chromosome and allozyme similarities (Sharman et al 1989;Eldridge et al 1991aEldridge et al , 1991bEldridge et al , 1994. However, the use of chromosomes to provide definitive species identification is limited by the technique's requirement for living tissue from which rapidly dividing cells can be cultured for analyses (Eldridge and Spencer 1997;Loupis and Eldridge 2001). Now with DNA studies becoming a diagnostic tool for species identification, it is mandatory that this research be used in identifying which subspecies/races of P. lateralis likely occurred on DI.…”