Tuatara genome mapping

University of Otago researchers are working on an "ambitious" project to map the tuatara's genome, which, when completed, will be one of the biggest genomes assembled.

Prof Neil Gemmell said the project had attracted interest from the international science community due to the uniqueness of the species as the only member of an archaic reptilian order.

This meant the species was a link to the now extinct stem reptiles from which dinosaurs, modern reptiles, birds and mammals evolved.

This and the importance of the species to New Zealanders meant it was an exciting project to work on, Prof Gemmell said.

"There are few things that are more iconic in New Zealand's fauna than the tuatara."

Having a genome sequence could help conserve the species by providing information on how it wards off disease. It could also add to knowledge about how global warming might affect the ratio of females to males, with sex being determined by the temperature of eggs during incubation.

"With rising temperatures you tend to get more males, so there is a suggestion that if climatic change continues in the direction that it is, then we may get a more male-biased population."

Mapping of the DNA began in May and the entire project was expected to be completed by the end of next year, he said.

Prof Gemmell said the tuatara's genome had between five billion and six billion base pairs of DNA sequence, compared to three billion in the human genome.

The project had compiled about 300 billion base pairs of information, which took up about two terabytes of data.

Prof Gemmell said the tuatara had been identified as being among the 100 most important species to have their DNA sequenced.

The project was funded by the Allan Wilson Centre and supported by the Otago University Centre for Reproduction and Genomics, New Zealand Genomics and Illumina Asia Pacific.

The researchers worked alongside Northland-based iwi Ngatiwai, which has guardianship over one of New Zealand's largest populations of tuatara, to get blood samples.

-vaughan.elder@odt.co.nz