Yangtze River Dolphin’s Genes Indicate Humans Caused Its Extinction

By Gemma Tarlach | October 29, 2013 11:00 am
river dolphin baiji

A free-ranging baiji swims in China’s Yangtze River in this undated photo. Credit: Kaiya Zhou

The verdict is in regarding the recent extinction of a Chinese river dolphin: humans, not a glitch in the animal’s genes, were responsible.

Researchers reconstructed the entire genome of a baiji (Lipotes vexillifer), or Yangtze River dolphin, using tissue remains from a specimen frozen since 1985. The baiji, poetically known as the “Goddess of the Yangtze,” is a symbol of the challenge of marine conservation in the face of expanding human activity.

Rapid Decline

As recently as the 1950s, there were an estimated 5,000 baiji living in China’s Yangtze River. The country’s rapid industrialization, however, resulted in habitat loss and water pollution. That coincided with a rapid decline in the dolphin’s numbers. The last confirmed baiji sighting was in 2004. Two years later, after a broad survey failed to find a single animal, the species was declared “functionally extinct.”

A research team has now sequenced the genome of a male baiji and then resequenced the genomes of three additional specimens to create a broader understanding of the species’ evolution. The findings appear today in Nature Communications.

Dolphin Genetics

Researchers found evidence for a genetic bottleneck that reduced diversity in the species some 10,000 years ago, coinciding with a rapid decrease in global and local temperatures. However they concluded there was no genetic reason for the animals to go extinct, and that human activity alone was to blame.

Although the researchers who sequenced the baiji’s genome focused on reconstructing the species’ past to understand its evolution, the results of their work could one day be used to resurrect “the Goddess of the Yangtze” through de-extinction.

CATEGORIZED UNDER: Living World, select
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  • http://anniedeezy.tumblr.com/ Annie

    Thanks, China.

    • Bruno Daniel

      Yeah…. thanks China for being super industrial enough to make literally anything that Americans need… For supplying the American demand. Try thinking.

      • http://anniedeezy.tumblr.com/ Annie

        Does that make what they did right?

        American need isn’t what caused this problem. American business and demand moved to China in the first place because practices which are super illegal here in the States are just fine and dandy there.

        Does that make it okay? Of course not. But if a country doesn’t already have such lax rules in place, no unscrupulous business owners (read: most industrial goons) would throw their money at them.

        • ChuckRamone

          Do you know that in the 80s and 90s, America was always hounding China to open up its markets? American businesses were salivating at the thought of that huge untapped market. The greed of American business owners is what brought them to China where they could get things done cheaply. There was no consideration of what’s legal or not there.

          • http://anniedeezy.tumblr.com/ Annie

            Did you know that when animals in America go extinct, it is exactly America’s fault?

            China isn’t a sniveling wuss, they are a superpower. This isn’t like the countless nations the first world literally dumps toxic waste on because they’re helpless to do anything about it; whether they felt pressured or not, they still have a deplorable record of giving zero fucks about the environment.

            To make the point abundantly clear, although I think it’s silly that people are so nit-picky that I have to, this doesn’t excuse the wrongdoings of other countries. This, however, is an article about China and a sad, awful thing that China has done.

          • ChuckRamone

            This couldn’t have happened without a globalized economy where most of the manufacturing and the associated toxic waste are in China. Yes, China did it. And, yes, they did it by feeding the world’s demand for cheap goods. Most of the big companies whose manufacturing is based in China are not Chinese companies. Do they need to improve their environmental protection standards? Yes. Will they be able to do that without slowing down their development and industrialization, and giving up business to other countries who’d be happy to destroy their environments to cash in? No.

          • http://anniedeezy.tumblr.com/ Annie

            I agree, but I think it’s overreaching to assume that the majority of blame should leave China’s shores.

            A loose analogy would be if I had a starving family and someone offered me $100 to kill someone, and I did it, would it be less reprehensible? No, but it doesn’t take away from how sad my family’s situation is.

            China is the murderer and the foreign market is the one soliciting the murder.

          • ChuckRamone

            I don’t know how much worse China is in regard to destroying its environment and having lax standards, but remember that when England and America were industrializing, you had books like Charles Dickens’ novels and Upton Sinclair’s The Jungle coming out.

          • disqus_atlq8Zmtsd

            The United States has its own track record of environmental degradation and extinctions.

            As long as you believe that the United States is evil for draining its wet lands in the mid west in order to feed itself and large portions of the world, your argument is at least internally consistent.

  • Mike Hilty

    In China they say “better to have factory than fish”(or mammal)

    • Goodman

      Are you sure this problem is only exists in China ? I think it’s a global issues

  • cobrawolf

    They will just blame it on the Imperial Japanese Army

  • Thayne Belasco

    The human race is responsible for the atrocities that are happening to our enviroment! Our planet is dying!

    • Notafanboy

      Well go jump off a bridge, then. Show us how you’re not going to take it anymore.

  • German_reader

    “the results of their work could one day be used to resurrect “the Goddess of the Yangtze” through de-extinction.”

    how would that work?

    • Ian T

      It’s just false solace that constantly comes up when extinctions occur, and people realise the massive cultural and environmental loss. With the Baiji, as with the Thylacine in Tasmania, this ghost animal becomes a powerful iconic symbol to people once it becomes extinct. “De-extinction” is nonsense, given the population required for a viable breeding population. We can’t even seem to save living species once they fall below a certain number (the Javan rhino is likely to be next), although it is possible (the Chatham Island black robin), with sufficient commitment, suitable environments and money. It would be much simpler to have recognised the true value of these species and conserved them properly in the first place, but there isn’t where the majority of human priorities lie.

  • http://anniedeezy.tumblr.com/ Annie

    …Barred owls are “of least concern”, meaning that they aren’t remotely extinct.

    It goes without seeing that not every “envirokook” feels that hunting other species to the point of extinction is a prudent idea. In fact, when thinking of the mentally ill in environmental law, what comes to mind are the ones who would rather see humans go extinct; to them, human interference in an animal’s depopulation is unconscionable.

    • Notafanboy

      I never said the Barred Owls are extinct, rather that the far left in this country are trying to hunt them down and murder them so they can protect the endangered status of an animal. That status gives the left wing eco-zealots power to control people by establishing boundaries and bans on behaviors they deem undesirable. If they lose that status, they lose the ability to control certain practices in those areas. This proves that the stated motivation these people claim are less than truthful.
      I’ve seen these people up close. They are the closest thing to evil you will ever meet. Many of these groups openly call for the culling of humans. To them any action taken by humans is unnatural. It’s sickening, but it gets worse. They actually have an entire political faction, the largest political party in the US, that panders to them. These people are actually allowed to become professors and “teach” our kids.
      But let me guess, you think there are “moderate” ecowarriors? Sure there are. Just like the “moderate” Muslim who shyly claim to be against extremism, but secretly supports the actions of lunatics. The actual sane conservationists are outnumbered 10,000 to 1. Ted Nugent makes more sense than these freaks.

  • Notafanboy

    I agree with the overall sentiment, but two points need to be made. First, it is not our responsibility to preserve diversity (a human concept), but rather to limit the damage caused by our industry and society through excessive pollution.

    Secondly, and most importantly, a change in the environment caused by humans isn’t automatically “damage.” All life alters it’s environment. Take hydroelectric dams for example. They do change the environment downstream and some species suffer negatively.

    For clarification: Rerouting a river or building a canal is NOT an example of environmental damage. However, dumping industrial waste into a river is.

    Ultimately, there is nothing that we can do that nature won’t find an answer for. We like to consider ourselves more powerful than we really are, but we are not the be all and end all of creation.

    • disqus_atlq8Zmtsd

      When you look at wobbling food webs and alarming reduction of biomass (especially biomass useful to humans) in many marine ecosystems, it is undeniable that we are damaging the earth, even if your definition of damage is only change that is negative for us.

      You don’t have to be a “bleeding heart” to see that.

    • Ian T

      Pollution is one issue, but destroying ecosystems through clearing, damming, overfishing, etc. are also major factors in the way humanity obliterates biodiversity. The real problem, and the reason humans are so influential, is the world population of 7 billion people. That number is why we make such a huge (and negative) difference.

  • uiyfif

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