New method for non-destructive DNA extraction

Researchers at the University of Otago have developed a new method to obtain ancient genomic data without compromising the original material, creating new opportunities for museums and archaeological collections around the world

"Ancient DNA was not necessarily destructive," said lead author Lachie Scarsbrook

The study, published in the international journal Molecular Ecology, presents a new method for obtaining genomic data from small vertebrate remains without causing visible damage to the underlying skeleton

"This will help analyze not only materials in museum collections that are too small for destructive sampling, but also rarer and more valuable materials, both culturally and scientifically,

The research, which was carried out while Mr Scarsbrook was completing his MSc in the Department of Zoology, used contemporary and extinct populations of pantoed geckos as a case study, representing the first access to the mitochondrial genome of a New Zealand lizard

Newly sequenced DNA data has allowed researchers to understand and show how tectonic activity, climate change and human influence are affecting New Zealand regional populations of the whole-toed gecko (Hoplodactylus duvauceli)

Mr Scarsbrook, who is currently completing his PhD at Oxford University's Paleogenomics and Bioarchaeology Research Network, said the research also involved the process of scientific progress

"After a redesign and some changes, we achieved our goal, which shows that perseverance in the face of failure is key if you want to help advance science

Mr Scarsbrook explained: "The deep split between the South and North Island reflects a long period of isolation prior to the formation of the Cook Strait, while South Island populations show geographically the same maximum ice age as the last ice age peak.

"The significant loss of genetic diversity in North Island and South Island populations demonstrates the influence of humans and introduced predators

Dr Nic Rawlence from the Genetics Laboratory is the director and co-author of the study

One of the results of the study, he said, was that the understanding of New Zealand geckos when humans arrived was now a fresh start

Dr Lawrence said: "It was previously thought that the bones of different species of geckos could only be distinguished by size, but surprisingly, CT scans and ancient DNA have shown that we can actually distinguish between different species of geckos by shape alone

"It turns out that size doesn't matter, which means what we know about New Zealand geckos when humans arrived is now a paleontological blank

Dr Rawlence said continuing research projects would use these new technologies, working with the New Zealand Department of Conservation and Māori iwi to reconstruct the ecological history of lost New Zealand geckos and skinks (identification based on size has puzzled scientists), and Frogs and lizards

"The long-term preservation of limited specimens is a major concern for curators around the world, and the findings of this study will not only unlock molecular secrets, but also potentially enable similar genetic analyses of vast natural history and archaeological collections worldwide

Ancient mitochondrial genomes recovered from small vertebrate bones through minimally destructive DNA extraction: Phylogeography of the New Zealand gecko genus Hoplodactylus