Without flying, nasty and famously bad at sex, New Zealand’s critically endangered kākāpō, the world’s heaviest parrots, have surprisingly good genetic health after 10,000 years of inbreeding, according to new research.
An international team of geneticists, biologists and ecologists recently examined 49 of the genomes of birds to understand how small populations were doing genetically, given their impending extinction 30 years ago. The team was amazed at how the species, which now totals just over 200, has avoided the kind of harmful mutations that affect other animals on the verge of extinction. His research is published today at Cell Genomics.
“The main finding of this study is that although the kākāpō is one of the most endangered and endangered bird species in the world, it has far fewer harmful mutations than expected,” Nicolas said. Dussex, lead author of the paper and researcher at the Center for Paleogenetics and Stockholm University, in an email to Gizmodo. To explain this unexpected result, Dussex’s team suggests a counterintuitive genetic phenomenon called purge, whereby endogamous populations end up having fewer harmful mutations in their genetic code instead of more.
“It seems that a factor that favors the purge is the rate of descent and the rate of increase of inbreeding,” Dussex added. “If inbreeding increases very rapidly, a large number of harmful mutations will be exposed to natural selection in a very short period of time … Conversely, if inbreeding gradually increases, harmful mutations will be exposed gradually, in a larger number of generations and not in all individuals at once. ” In other words, because the kākāpō spawned in isolation on the islands of New Zealand for over 10,000 years, there was never a fatal accident due to genetic corruption.
The kākāpō do not appear to be survivors. The bird, also called an owl parrot, fits into the same category as giant pandas and quokkas as creatures whose survival seems purely aesthetic, at least for the indestructibled ull. The kākāpō like to eat fruit, especially rhyming fruit, nest in shelters at ground level and can live quite a long time, maybe up to 80 years. HowThey are often infertile and sometimes have a bad judgment: a kākāpō famously called Sirocco He tried to mate with the head of a wildlife photographer.
Hunted by invasive mustelids (which were introduced by humans to eliminate booming rabbit populations), the kākāpō may have followed in the footsteps of the dodo similarly to land, but the surviving bird populations moved to the free islands of predators of New Zealand in the 1980s. Since then, attempts to reduce inbreeding and maintain genetic diversity in the tiny population have been instrumental.
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“We show that the continent’s only male survivor, Richard Henry, has more harmful mutations than birds on Stewart Island,” said Love Dalén, co-author of the paper, a researcher at the Center for Paleogenetics and the Swedish Museum of Natural History. . statement. “Therefore, there may be a risk that these harmful mutations will spread to future generations.”
Richard Henry the Kākāpō was found in Fiordland, southwestern New Zealand, and his genetic diversity and virility were essential to withdrawing birds from extinction. At the same time, however, Henry’s DNA has more harmful mutations than the Stewart Island kākāpō. (Richard Henry is named after a human who he devoted much of his life in the early twentieth century to save the species. A handful of New Zealand conservationists have taken up the work of Henry the Human, many of whom co-authored the paper published today).
The genetic success story of kākāpō could be contrasted with that of wolves on Royale Island, the population of about 50 people in 2011 fell to two in 2016 alone after a new individual wrapped in genetics of the group, already dangerously endogamous. A study of this situation, published last year, in Evolution Letters, he indicated that sometimes pushing high genetic diversity too quickly into a group with low genetic diversity can lead to population collapse.
It is also, perhaps, a warning to the kākāpō, as the bird does not leave the proverbial forest and, apart from genetic diversity, has to worry about predatory paths and weasels roaming its territory. Recent research will help refine the breeding program approach, Dussex said, and new island populations could be established now that researchers better understand how all of the current population relates.
If the researchers managed to keep the kākāpō population genetically healthy, it would be a great victory in the battle for the survival of the animal. There are many threats ahead, but the powerful green bird has a chance.
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