Ancient DNA from Mexico’s mammoths reveals unexpected — and unexplained — genetic mysteries
For the first time in tropical latitudes, scientists have led to the ancient DNA of the only endemic mammoth in North America and the central: the Columbian mammoth. Research has revealed unexpected – and still unexplained – genetic differences that made these animals distinguish from their northern counterparts.
Columbian Mammoths (Mammuthus columbi) were approximately 13 feet (4 meters) in height and dominated on their Woolly mammoth (Mammuthus primigenius) Parents, with whom they coexisted and even agreed. Their fossils were discovered in Canada, the United States, Mexico and Central America. But the information on how they have evolved in the Americas is not clear.
Construction from 2019 from Felipeles International Airport in Santa Lucía, Mexico, discovered a vast wealth of Pleistocene fossils (2.6 million to 11,700 years), including more than 100 Colombian mammoths.
The pure quantity of fossils, said Federico Sánchez-QuintoA paleogenomic at the International Laboratory of International Research of the Human Genome of the National Autonomous University of Mexico (UNAM), prompted it to reach out to those involved in excavation. This is what finally led to the team’s DNA work.
When an animal dies, its DNA deteriorates quickly, something that is more composed by heat. In this regard, “DNA is like an ice cream,” said Sánchez-Quinto to Live Science, because it preserves better in the cold. Nevertheless, Ángeles Tavares-Guzmán, co-author and engineer of biotechnology, was “full of hope”, especially since another team recently extracted the old DNA from a DNA in the same way hot climate.
In relation: “ Closer than people do not think “: the woolly mammoth ‘de -extinction’ ‘approach of reality – and we have no idea what is going on then
In total, scientists sequered 61 mitochondriage genomes of 83 mammoth molars. Five radiocarbon samples indicate that they were between 11,000 and 16,000 years old. Research was published August 28 in the journal Science.
By bringing together ancient DNA, scientists can better retrace the path that mammoths have taken through the Americas. But in this case, the sequencing revealed confusing results.
Search for 2021 indicates that a line previously unknown to the Eurasian steppe mammoth (Mammuthus trogontherii) coupled with woolly mammoths (Mammuthus primigenius) Before crossing Beringie – an icy terrestrial bridge – in North America 800,000 to 400,000 years ago, which finally led to the species of Colombian mammoths.
A theory is that the Columbian mammoths have continued to migrate south until it is ultimately what is Mexico – a theory that would be supported by finding animals with DNA similar to Mexico and further north.
But instead, the team has revealed evidence that Colombian mammoths in Mexico are genetically different from those in the United States and Canada. In other words, although Mexican Colombian mammoths are the same species as us and Canadian Colombian mammoths, their specific genetic composition is different.
The team also found that the common ancestor of Mammoths in Mexican Colombia diverged much earlier than those who migrated to and stayed in the United States and Canada.
The co-author of the Eduardo Arrieta-Donato study, researcher at the International Laboratory for the Research of the Human Genome of UNAM, suggested thinking of this common ancestor like the large, rear, great-grandmother of Mexican mammoths. “”[She] was already a hybrid of steppe mammoths and woolly mammoths of Béringia, “he said. While his descendants rose and migrate south, they may have been isolated from other North American mammoths, which could explain this genetic uniqueness, added Arrieta-Donato.
This uniqueness suggests that the evolution of the Columbian mammoth “was much more complicated than we thought,” said Sánchez-Quinto, “and that Mexico carries a significant genetic variation which is not present in other places”.
Interestingly, other species of the pleistocene excavated in Mexico also have divergent genetic lines compared to their northern parents. For example, a genetic variation has also been observed in the Pleistocene black bear (Ursus Americanus) and in at least one mastodon ) – an extinguished type of mammoth resembling elephants. A species with a genetic variation separating them from their northern counterparts is surprising; Three species with similar genetic distinctions indicate that something extraordinary has happened as species migrated to the south.
The new research “raises several new and very interesting questions,” said Love DalenProfessor of evolutionary genetics at the Palaeogenetic Center for the University of Stockholm which was not involved in the study.
“I am very impressed that Federico and his colleagues managed to obtain DNA from such highly degraded samples!” He told Live Science in an email. “It is a gigantic feat to obtain the DNA of the tropical samples of the Pleistocene!”
Tavares-Guzmán, Arrieta-Donato and Sánchez-Quinto noted two important aspects of their article. First, this successful extraction of old DNA in Mexico questions the expectation that DNA is less likely to be extracted in hot climates. And secondly, that their work shows that DNA analysis does not need to be exported to other countries. “World South Laboratories have the ability to carry out these projects,” said Sánchez-Quinto. “Sometimes what we miss is money.”
The new research suggests that the species of Mexico seem unique. Discover exactly why it requires obtaining more DNA samples from a larger geographic distribution. “It is more than justification to further project the biodiversity that occurs in the tropics through time,” said Sánchez-Quinto, “who, ideally, should be carried out by local scientists”.
Mammoth Quiz: Test your knowledge of freezing animals
