Inbreeding contributes to southern resident killer whale’s low population growth: study – BC
A new study finds that high levels of inbreeding among endangered southern killer whales likely contribute to their low population growth.
Study published Monday in peer review Natural ecology and evolution The journal found that the iconic species that lives in the North Pacific has the lowest genetic variation and the highest genetic inbreeding among the five killer whale populations analyzed.
“The big finding from this study is that the more highly inbred individuals are much less likely to survive to old age or survive the reproductive years,” said report co-author Marty Cardos told Global News.
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Using relatively new techniques and archival tissue samples, the researchers sequenced the genomes of 100 southern-dwelling killer whales and 47 other killer whales. Tissue samples ranged in age from the early 20th century to the last decade.
Scientists once thought that individuals with “recent common ancestry” were inbred, but have found at least one example of direct parent-child interbreeding among Southern inhabitants.
Kardos said inbreeding appears to affect the “fitness” of the population, limiting its growth for decades.
“It can be associated with an increased risk of getting sick and can affect behavior, neurological function, immune function and metabolism,” explained a geneticist at the Northwest Fisheries Science Center.
“Genomes are large, with tens of thousands of genes in them, any of which can carry deleterious or mutated versions of the gene, and inbreeding really does affect their effects on survival and reproduction. will be exposed to
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Fewer than 80 killer whales remain in the south.
Given that the species has been legally protected for decades, Cardos said scientists wondered why its growth rate did not match that of other groups of killer whales in the region. These protections remain important, he added.
“We’ve known for about a decade or so that the best population models suggest that the population is very likely to decline in the future. This study changes that. Instead, it just provides an explanation.”
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