NEWPORT, Ore. – Analyzing thousands of genetic markers in a Pacific albacore tuna, researchers at Oregon State University have learned that just seven dozen of these markers are needed to determine which side of the zone- medium that fish come.
The scientists also found that fish from different hemispheres mate and sometimes breed with each other.
Published Tuesday in Evolutionary applications, the findings are an important step towards a better understanding of the population structure of sex which is a vital and inexpensive source of protein for people worldwide.
Albacore in the North and South Pacific oceans are currently managed as separate stocks. The OSU study reinforces this approach while also opening the door to further research on crossover and interfaith that can be used to modernize management strategies across the Pacific.
“Albacore supports one of the largest and most valuable fisheries in the world and one that is particularly important on the west coast of North America,” said Kathleen O’Malley, associate professor linked to OSU College of Agricultural Sciences. “Much work has been done to understand the structure of the albacore stock worldwide, but little research has been done in the Minch and it has raised so many questions. to answers. “
O’Malley, who is also a fishing geneticist in the state of Oregon, noted that previous research involving tagged fish has not shown albacore movement from one side of the equator to the other. At the same time, previous genetic data provided no way to tell whether fish were from the North Pacific or South Pacific – hence the lack of understanding of the relationship between the two populations.
O’Malley and postdoctoral research fellow Felix Vaux, who led the study, looked at DNA from 308 fish from 12 areas around the Minch. They identified nearly 13,000 genetic markers – DNA sequences with known physical locations on chromosomes – and learned that less than 100 of these markers told the story of the part of the ocean from which fish came.
“We identified 12,872 tokens and were able to differentiate between North and South Pacific albacore by using only 84 of them,” Vaux said.
Those 84, he said, appear to be “under selection” and may reflect changing differences between the two albacore stocks. In any population, individuals with locally altered symptoms are most likely to reproduce, meaning that selection over time increases the frequency of these symptoms. With continuous, intense selection, variable symptoms become universal or near universal in population or gender.
“There is no absolute gender for albacore to compare our data, so we have not been able to determine which genes underlie the apparent mutually exclusive differences,” he said. O’Malley. “Furthermore, we found that some fish have a mixed genetic background – indicating that albacore from the North and South Pacific spawn at the same time and breed together. We also found an albacore with genetic images of the South Pacific in the North Pacific, providing evidence for migration across the equator not previously identified by physical tagging data. “
Future studies, she said, will use these genetic markers to more in-depth study of interfaith between North and South Sea albacore as well as hemisphere migration.
O’Malley, who heads the State Fisheries Genomics Lab at OSU’s Hatfield Marine Science Center, says both genetic and demographic links, while important for effective management and conservation strategies, are not well understood in most marine species.
Genetic diversity is an important tool for populations trying to adapt to climate change and other environmental impacts, she said. With more variation, some people in a population are more likely to be fit to withstand the changes and bring up children who are also capable of thriving in the changed environment.
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Collaborating with O’Malley and Vaux on this research were Sandra Bohn from the State Fisheries Genomics Lab and John Hyde from the National Sea Fisheries Service. Vaux is now a graduate associate at the University of Otago in Dunedin, New Zealand.
The study was funded by the Saltonstall-Kennedy Grant.
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