Analyzes show that the Colombian mammoth that inhabited North America during the last ice age was a hybrid between a woolly mammoth and a previously unknown line of mammoths. In addition, the study also provides new insights into when and how quickly mammoths adapted to cold climates. About a million years ago, there was no woolly mammoth on Earth (also known as tundra mammoth, scientific name: Mammuthus primigenius) ; or the Colombian mammoth (scientific name: Mammuthus columbi) , because they haven’t evolved yet. The ancient steppe mammoths were their ancestors. Researchers have now managed to analyze the genomes of three ancient mammoth species, using DNA recovered from mammoth teeth that had been buried for 0.7 to 1.2 million years in the permafrost layer. in Siberia. This is the first time DNA has been sequenced and authenticated from specimens that are millions of years old, and extracting DNA from these samples has been a challenge. The scientists found that only a small amount of DNA remained in the samples, and that they were broken down into very small fragments. Love Dalén, Professor of evolutionary genetics at the Center for Ancient Genetics in Stockholm, said: “This DNA is very ancient. The specimens are thousands of times older than the Viking relics, and even more predated the existence of humans and Neanderthals”. The ages of the specimens were determined using both geological data and molecular clocks. Both types of analysis show that two of the specimens are more than 1 million years old, while the third is about 700,000 years old and represents one of the earliest known woolly mammoths. come. The unexpected origin of the Colombian mammoth Genomic analysis shows that the oldest specimen, about 1.2 million years old, belongs to a previously unknown lineage of mammoth genes. The researchers call this the Krestovka mammoth, a name based on the area where it was found. The results show that the Krestovka mammoth diverged from other Siberian mammoth species more than 2 million years ago. “This came as a complete surprise to us. All previous studies have shown that there was only one species of mammoth in Siberia at that time, called the steppe mammoth. But the Our DNA analysis now shows that there are 2 different genetic lines, which we here call Mammoth Adycha and Mammoth Krestovka . We can’t say for sure yet, but we think they may represent two different species,” said Tom van der Valk, lead author of the study. Teeth of the Krestovka mammoth. Source: CPG The researchers also suggest that it was the mammoth of the Krestovka lineage that “dominated” North America about 1.5 million years ago. In addition, analyzes show that the Colombian mammoth, which lived in North America during the last ice age, was a hybrid. Nearly half of its genome comes from the Krestovka lineage and the other half from the woolly mammoth. “This is an important discovery. It seems that the Colombian mammoth, one of the most iconic species of the Ice Age in North America, evolved through a crossbreeding that took place about 420,000 years ago.” – Dong Author Patrícia Pečnerová said. Evolution and adaptation in the woolly mammoth The second million-year-old genome, from the Adycha mammoth, appears to be the ancestor of the woolly mammoth. The researchers were therefore able to compare its genome with that of one of the earliest known woolly mammoths that lived 0.7 million years ago, as well as with the genome of a mammoth. sucking only a few thousand years old. This makes it possible for scientists to investigate how mammoths adapted to life in cold environments and the extent to which this adaptation evolved during speciation. Proving how this giant animal has “risen” strongly over the past millions of years under extreme cold weather. The analyzes show that gene variants associated with life in the Arctic, such as hair growth, thermoregulation, fat accumulation, cold tolerance and circadian rhythms , appeared in the million-year-old mammoth, long before the origin of the woolly mammoth. These results indicate that most adaptations in the mammoth lineage occurred slowly and gradually over time. “Our analysis shows that most of the adaptations to cold weather were present in the ancestors of the woolly mammoth, and we found no evidence for natural selection. faster in speciation,” said co-author David Díez-del-Molino. Like their modern relatives, mammoths were quite large. The largest known species reach a height of 4 m and a weight of up to 8 tons, with some particularly large males weighing more than 12 tons. Future research The new results open the door to a host of future studies on other species. Love Dalén and co-author Patrícia Pečnerová with a mammoth tusk on Wrangel Island (Arctic Ocean). Photo: Gleb Danilov About a million years ago was a time when many species of organisms flourished across the globe. This is also a time of great changes in climate and sea levels, and the last time the Earth’s magnetic poles change positions. Therefore, the researchers think that genetic analyzes on this time scale have great potential to explore a wide range of scientific questions. “One of the big questions right now is how far back in time we can go. We haven’t reached the limit for the longest. It is expected that we can recover DNA that is two million years old, and even more so. can even go back as far as 2.6 million. Before that, there was no permafrost where ancient DNA could be preserved.” Anders Götherström, Professor of Molecular Archeology and lead researcher at the Center for Paleontology. These findings are published in the journal Nature.

The warehouse was converted into an isolation area for infected people during the 1918 flu pandemic. Photo: According to Live Science “The research results, although not directly applicable to the Covid-19 pandemic, show that humans can eventually overcome their variants. This is being expected by the world in the context of the corona virus outbreak. evolved with many dangerous mutations today,” evolutionary biologist Sébastien Calvignac-Spencer, lead author of the study, told Live Science. According to Spencer, as now, when focusing on studying the virus that caused the 1918 flu pandemic, the research team questioned whether its new variants worked differently from the original? Since then, the team has studied six human lungs dating from the pandemic years of 1918, which are preserved in formalin at pathological archives in Germany and Austria. The researchers determined that three of the six sample lungs – two from young soldiers who died in Berlin, the other from a young woman who died in Munich – contained the 1918 flu virus. “The virus that caused the 1918 flu pandemic is still around today. But it’s more attenuated, mainly because we are descendants of people who survived the outbreak 103 years ago. Because So we’ve inherited some form of genetic immunity,” explains Calvignac-Spencer. Estimates suggest that the 1918 strain of influenza infected about 1 billion people, while the global population was only 2 billion. About 50-100 million people may have died in three consecutive outbreaks then. The first wave of the pandemic occurred in early 1918, it was less deadly than later waves: “The preserved lungs of two German soldiers were determined to be dead at this time”, the research team at the Institute of Robert Koch confirmed. The researchers extracted viral RNA from those lung samples. Both German soldiers died on the same day and when decoding the genome of the virus that killed them there was almost no difference. Spencer added: “But the form of the flu virus found in the soldiers’ lungs, is somewhat genetically different from the form of the virus that infected the young woman who died in Munich. Presumably, the woman. did not survive a subsequent outbreak.” The scientists also compared viral genomes from the US and Germany, and conducted laboratory studies with synthetic copies of virus samples. They wanted to learn to assess the infectivity and replication ability of different strains inside cells. The findings of German scientists also show that the 1918 flu virus has mutated to make the next outbreak stronger and more dangerous than the previous one, by evolving to overcome the human ability to “defence”. The genetic mutations that emerged between the first and second waves may have made the virus better adapted for human-to-human transmission, rather than between birds, its natural host. The other mutation may have changed the way the virus interacts with a human protein called MxA, which helps regulate the body’s immune response to new pathogens. Although the scientists are not sure how the variants changed the “strength” of the virus, “it can be predicted that these changes helped the virus avoid one of the mechanisms by which cells respond.” to kill the flu virus,” Calvignac-Spencer said. The evolution of the virus that caused the 1918 flu pandemic has similarities to the current Covid-19 pandemic, such as consecutive outbreaks with many different strains, and the following outbreaks are more dangerous than the previous one. . Thanks to the advancement of science, today when understanding the Covid-19 pandemic, researchers can better understand the 1918 influenza pandemic: “The more we understand about the current pandemic, that The more we can understand the pandemic in the past, rather than vice versa,” Calvignac-Spencer emphasized. One significant advance is that researchers have been able to accurately sequence the viral genome in human tissue preserved in formalin for more than 100 years – something that has hitherto been thought to be very difficult. “Thanks to new techniques, the study ended up being much easier than we expected,” added Calvignac-Spencer, adding: “We can now sequence the viral genome from infected humans. buried in permafrost for up to 1,000 years, because the cold can help preserve DNA even longer.” The team of German scientists also wanted to sequence viral genomes that could have been stored in the bodies of ancient Egyptian mummies – the earliest mummies are about 5,000 years old.”The mummies were prepared to prevent biological processes, and that’s exactly what we want. So we will also embark on research to better understand other diseases of the past,” the German scientist said. about the group’s future plans.

However, Siamese fish do not become such vivid “works of art” on their own. The color and shape of the fins of this fish are the product of a millennium of breeding. According to Yi-Kai Tea, a PhD student at the University of Sydney who studies the evolution and characteristics of fish species, “Literally, the development process of this fish is almost the same. with the domestication of dogs”. A new study, published in April in BioRxiv, finds that humans began domesticating Siamese fish at least 1,000 years ago through sequencing the species’ genome. During a millennium of careful breeding and crossbreeding, Siamese fish are now extremely diverse in appearance. However, this also means that wild, purebred individuals of this species must undergo major genetic changes. The authors of this study say that by sequencing and conducting genetic studies of the Siamese fish, they can gain a lot of information about how it was domesticated, bred, and genetically modified. The Siamese’s intricate coloration and “matchy” fins are the product of a millennium of carefully selected breeding. Yi-Kai Tea hailed it as “the first major study to help identify the genetic basis of beauty” in this fish. All 73 species of Siamese fish are native to Southeast Asia. But the most common species sold in aquarium stores and markets is the fighting fish. This strain is much more colorful than most other purebred varieties of the Siamese family. “The purebred Siamese will often look very different from the ornamental Siamese,” said Young Mi Kwon, a researcher at Columbia University and lead author of the study. “They have short fins, are somewhat duller in color and lack the prominent fin walking commonly seen in ornamental Siamese breeds.” While domesticated Siamese are usually very aggressive and do not live together, their domesticated individuals have a more peaceful disposition. “This may be because the Siamese aquarium lines were originally domesticated for fighting, like fighting cocks,” Kwon added. Siamese fish has a history of 1,000 years. In the late 19th century, breeders began to focus on creating varieties of ornamental fish, which later became extremely popular in the West. “This history has shaped the ornamental Siamese fish we see today, a truly magnificent fish with a fiery temperament,” commented Kwon. To determine the exact history of the formation of the ornamental Siamese fish we see today, Kwon and his colleagues collected DNA samples from purebred Siamese and house-raised Siamese fish, and then proceeded to analyze them. their genome sequences. “We were surprised by the evolution of the Siamese fish that lasted at least 1,000 years ago, which makes it one of the oldest known fish,” Kwon said. While previous studies have shown that Siamese fish were bred as early as the 13th century, recent discoveries have proven that they began to be bred long before that. The study also highlights why breeders are able to create dozens of different varieties of Siamese by color, from red, yellow and blue, to Siamese with large fins, small fins and even multiple colors per individual. Just imagine the new shape of a Siamese fish, it can completely be created and exist in reality. “Many traits, which breeders are selecting for, are regulated by very few genes that have a great deal of influence,” Kwon said. “This means that it won’t take a lot of cross-breeding to get them to have their own characteristics or traits that you want your fish to have.” The researchers also found that ornamental Siamese fish are genetically distinct from purebred Siamese fish. However, they were surprised to discover that the ornamental Siamese had crossed with purebred fish. This crossbreeding may have been the result of the Siamese being released into the wild, which could potentially undermine efforts to preserve the purebred of this fish. “The ornamental Siamese fish will most likely dominate the natural environment, if they are more suitable to the habitat than the purebred fish,” Kwon emphasized. Many purebred Siamese fish breeds are in danger of extinction and the main cause is habitat loss. By studying in more detail the evolutionary history of this fish, the researchers hope to improve our understanding of how other species are bred and genetically engineered. Although much remains to be learned such as how crossbreeding affects Siamese fish, genetic engineering has resulted in the creation of many splendid Siamese fish of stunning colors and shapes that were previously available. This may never have existed. Sapphire According to the New York Times