An international research team has investigated the profound genetic impact of hunting on northern elephant seals. Experts found genetic scars in these animals that were once hunted until they were close to extinction.
The findings of this study have been published in the journal Ecology and evolution of natureshowing that these genetic effects persisted for decades after the seals narrowly escaped extinction.
Elephant jaw on the verge of extinction
By the beginning of the 20th century, northern elephant seals were nearly exterminated by hunting and their numbers were declining dangerously.
Experts noted that extensive hunting by commercial sealers between 1810 and 1860 largely removed the northern elephant seal from its geographic range, and by the 1890s it was extinct.
Dr. Josef Hoffmann, lead author of the study and head of the Department of Evolutionary Population Genetics at the University of Bielefeld, explained: “Genetic analyzes show that the population probably declined to less than 25 animals at that time.
Such drastic population declines can destroy the species’ genetic diversity, increasing the risk of inbreeding and jeopardizing survival. However, one bright ray of hope in this grim story is the recovery of northern elephant seals.
Despite the odds, the population has rebounded to about 225,000 by 2010. How did this near-extinction event affect their genetic diversity and health? This study offers some surprising revelations.
Beyond Extinction: The Cost of Survival for Seals
The team used a sophisticated approach to research, combining genetic data, health records, population size modeling and genetic simulations.
According to the findings, the drastic reduction of the population led to the loss of useful and harmful genes from the gene pool of the northern elephant jaw. These effects were not observed in their southern elephant jaw counterparts, which avoided such dramatic reductions.
Severe reductions in genetic diversity, including the loss of beneficial 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 natural threats. Dr. Kanchon K. Dasmahapatra, the study’s lead author, said as the outbreak.
Harmful mutations caused by population decline
Each species carries some harmful mutations that are hidden, but inbred individuals may reveal these health threats.
The team looked at key health characteristics, such as body weight, eyebrow thickness and susceptibility to disease.
Surprisingly, we found no signs of health problems associated with inbreeding. “We believe that drastic population reductions may eliminate many harmful mutations.” Dr. Hoffman said.
“Our study shows how the unique population history of a species shapes its genetic diversity,” Dr. Dasmahapatra noted.
“Each species responds to threats differently, so individualized approaches are necessary,” Dr. Hoffman said.
Save seals from extinction
The findings of this study have wide implications in the field of conservation genetics. The northern elephant seal serves as a pivotal case study in the genetic consequences of population bottlenecks.
By understanding the effects of declining genetic diversity, conservationists can gain insight into how other species may be under similar threats.
Understanding the genetic and fitness consequences of human bottlenecks is crucial for biodiversity conservation. “However, studies of bottleneck populations that combine genomic approaches with fitness data are rare.”
This knowledge is essential in formulating strategies that not only aim to preserve existing genetic diversity, but also strengthen resilience in the face of future challenges.
Bridging science and politics
Given the revelations of this study, there is an urgent need to bridge the gap between scientific research and policy making. Effective conservation strategies require coexistence between empirical evidence and regulatory frameworks.
Policymakers should consider genetic factors when devising conservation policies and ensure that efforts to restore or conserve species are both scientifically and practically feasible.
This integration of science and policy can pave the way for innovative management practices and adaptation that enhance the resilience of biologically diverse ecosystems and protect them for future generations.
“The northern elephant jaw provides a compelling opportunity to examine the complex interplay between population decline, genetic load dynamics, and fitness,” the study authors wrote.
The northern elephant seal is a classic example of a wild vertebrate that is thought to have had at least part of its genetic load wiped out as a result of a severe bottleneck.
This study was published in the journal Nature Ecology & Evolution.
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