Seal species carry “genetic scars” after being hunted to the brink of extinction, new research shows.

Northern elephant seals have made a remarkable comeback after narrowly escaping extinction by hunting, but new research shows persistent genetic effects in the current population.

Hunted for the oil in their glands, genetic analysis shows that the hundreds of thousands of northern elephant seals that lived in the Pacific Ocean dwindled to fewer than 25 animals by the turn of the 20th century.

The population has since recovered to around 225,000, but new research led by the universities of York and Bielefeld (Germany) and in Ecology and evolution of nature– It shows that the drastic reduction of the population has led to the loss of many genes from the gene pool of northern seals, which affects their genetic diversity and health.

A threat to survival

The researchers, who combined genetic data, health records, population size modeling and genetic simulations to conduct the study, did not see a similar pattern in the closely related southern elephant seal, which did not experience a near-extinction event.

These findings show how drastic population declines can destroy a species’ genetic diversity, increasing the risk of inbreeding and threatening its survival. According to the researchers, they provide important insights for species conservation and ecosystem management.

A unique population history

The study’s lead author, Professor Kanchon Dasmahapatra, from the Department of Biology at the University of York, said: “Our study shows how the unique population history of a species shapes its genetic diversity.

Greatly reduced genetic diversity, including the loss of useful gene copies, may impair the ability of northern elephants to cope with future environmental changes, including those caused by anthropogenic climate change, changes in the species’ habitat, or even threats. Naturally, disturb. as an outbreak.”

The lead author of the study, Professor Josef Hoffmann of the University of Bielefeld, added: “All individuals of a species have some harmful mutations, although their effects are usually hidden. However, inbred individuals may face health problems when these mutations become apparent. .

We looked at several key health traits in these seals, including body weight, glandular thickness and susceptibility to disease. Surprisingly, we found no signs of health problems related to inbreeding. We believe that drastic population reductions may eliminate many deleterious mutations. “