Scientists to sequence orcas’ DNA in effort to save them from extinction
SEATTLE — A new scientific effort will sequence the genomes of critically endangered Pacific Northwest orcas to better understand their genetics and potentially find ways to save them from extinction.
The collaboration announced Thursday involves scientists with the National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Center, the nonprofit Nature Conservancy and BGI, a global genomics company.
The project will sequence the genome — the entire genetic code of a living thing — of more than 100 southern resident killer whales using skin or other samples collected from live and dead orcas over the past two decades. Initial results are expected next year.
Scientists said the information could help explain, for example, whether internal factors such as inbreeding or genetic variation in immune systems are preventing the whales from rebounding.
The distinctive black-and-white orcas have struggled with pollution, boat noise and a dearth of their preferred prey, chinook salmon. The death of a young orca last month — despite a weeks-long international effort to save her — leaves only 74 in a group that has failed to reproduce successfully in the past three years. That's the lowest number in over 30 years.
"This will help us fill in some really critical gaps in our understanding about why the population is not recovering," Mike Ford, director of conservation biology at the Northwest Science Center in Seattle, said during a news conference in BGI's Seattle office. "As we fill in those gaps that will lead us to potentially better solutions."
Ford was lead author on a study published earlier this year that found that just two male whales fathered half of the calves that were born and sampled by scientists since 1990.
"Inbreeding could be a problem but we don't have enough data to study that in-depth," Ford said.
Inbreeding, for example, could affect whether a female orca will become pregnant, whether she'll have a calf or how likely that calf would be to survive.
Female orcas have been having pregnancy problems because of nutritional stress linked to lack of salmon. A multi-year study last year by University of Washington and other researchers found that two-thirds of the orcas' pregnancies failed between 2007 and 2014.
BGI Group will sequence the orcas' genomes and provide analyses and results to U.S. fisheries biologists and other scientists. They'll compare that research to the genomes of the Alaska population of killer whales that have been thriving, as well as mammal-eating transient whales.
Yiwu He, CEO of BGI Groups USA in Seattle, said that like so many others in the region, he and his family have been captivated by the iconic whales that spend time in the inland waters of Washington state.
"We very much want to do something to help," he said, adding the genome sequencing could help unravel questions about why the animals are not reproducing. He noted that BGI has extensive experience sequencing whole genomes of humans, plants and animals.
Ford said the results could put other problems faced by the whales, such as lack of prey or contamination, into context and could lead to different solutions. Whales found to have weaker immune systems because of lack of genetic diversity of immune-system genes, for example, could warrant more active treatment or management in the future.
"We don't know what we're going to find," Ford said, adding: "Maybe we'll learn something new about the population that we don't already know."