Kiwi scientists have contributed to the international effort to unravel DNA sequencing of the sheep genome, a scientific breakthrough that is expected to return $200 million to New Zealand's sheep industry in the next 15 years.
An article published this month in the prestigious journal Science represents eight years of work by 73 authors spread across 26 different institutions in eight countries.
The sequencing for the early work was done at the University of Otago and Baylor College of Medicine in Texas while more recent sequencing has been done at BGI in China, Baylor and the Roslin Institute in Edinburgh.
Researchers have now mapped about 99 per cent of the sheep genome, more than 30 million DNA variants have been identified and the quality of the work is much higher than initial efforts.
One of the paper's authors, AgResearch principal scientist John McEwan, from the Invermay Research Centre near Mosgiel, says New Zealand agriculture has already had valuable spinoffs from the new technology as the project has evolved over the past six or seven years.
"It has allowed us to do a whole lot of things that were previously impossible," he said. "It has also meant that the pace of discovery of gene variants affecting production and disease traits has advanced much more rapidly internationally."
McEwan said scientists here had led the world in the development of low, medium and now high density ovine SNP chips (single nucleotide polymorphism arrays), tools used in the genomic selection of sheep.
The 50K SNP chip is being used to develop genetic selection in the majority of New Zealand dual purpose sheep for 22 traits as part of the Beef + Lamb New Zealand and AgResearch-funded Ovita project.
Selection traits include facial eczema, parasite resistance, number of lambs born, meat yield and adult ewe liveweight. Commercial implementation uses lower density chips developed from 50K results.
"This technology has proven useful for hard-to-measure traits which are recorded late in life," McEwan said.
"We have also used this information to develop parentage assays that are now widely used in the industry and around the world."
A more recent technology, the HD chip, is being used in a joint Farm IQ partnership between the Ministry of Primary Industries, Landcorp and Silver Fern Farms to track eating quality traits in New Zealand-grown sheepmeat.
McEwan first started working in DNA sequencing research on cattle in 1998, an international project that cost about US$70 million before its completion in January 2009. Kiwi scientists then turned their attention to sequencing the sheep genome, which had cost between US$4m and US$5m internationally, and about US$1.5m in New Zealand.
Worldwide, the dairy industry has picked up genomics technology for breeding dairy cows with close to 100 per cent adoption rate in all OECD countries. Pig and chicken breeders are not far behind.
In sheep breeding circles, New Zealand was the first to release commercial genomic selection tests for sheep, but other countries are following suit, including Australia.
Sheep milking industries in France, Spain and Italy and meat sheep in Ireland and Britain are considering the technology.
"New Zealand has led from the front in taking the technology from mapping the sheep genome and putting it into practice," McEwan says. "We're talking about a specific technology from this DNA sequencing. There are a whole lot of other things you can get out of this technology, but we're not really there yet.
"There will be a lot of indirect spinoff benefits, but everyone to date has largely concentrated on genomic selection because it is understood and the benefits are reasonably clear."
While genetic progress may be slow, the gains made are permanent and cumulative, he says.
Benefits accrue over a long time frame, typically 15 to 20 years, before people see a full return for their investment.
McEwan estimated between 20 and 30 per cent of commercial sheep farmers in New Zealand are buying rams from stud breeders who are using DNA parentage or genomic selection technology.