Saturday , October 23 2021

Researchers examined how dogs arrived in America Country and Region


URBANA – Your poodle may have a French pedigree, but Siberia plays a major role in introducing dogs to America.

That's part of the research carried out at the University of Illinois and the Illinois State Archaeological Survey, based on dog remains, including two dogs that were buried back to back at an Illinois site just across the Mississippi River from St. Louis.

Burials, burial ceremonies, and about 50 dog fossils helped tell it, The News-Gazette reported.

The genetic code not only tells us about dogs, but also the potential for humans crossing the land bridge that once existed between Siberia and Alaska, said Ripan Malhi, a professor of anthropology and at the School of Integrative Biology.

The Illinois State Archaeological Survey has found several sites with dogs in them.

Not wanting to destroy valuable scientific and cultural relics, the Malhi team took samples from pet dogs that could approach 10,000 years, perhaps the oldest in America.

"The amount removed is about the size of a cavity (tooth)," he said.

Malhi works closely with Kelsey Witt Dillon, who leads the work of the mitochondrial DNA genome, following the mother dog line, as a graduate student here. (He is now a postdoctoral researcher at the University of California-Merced.)

In clean rooms – not traces of contaminants – the researchers extracted DNA. It was then sorted in another laboratory to create a "genomic library."

"DNA will give us millions of bits of DNA," Malhi said, some of which were contaminated long ago by microbes or even human disorders.

The first dogs in America came from Siberia, Malhi said, and most disappeared after European contact, an extreme version of the population declined with Native Americans after contact.

During the Ice Age (lasting up to about 14,500 years ago), sea level was lower and the area between western Siberia and eastern Alaska was all land, rather than the Bering Strait we know today. This region is known as "Beringia," and people (and dogs) can cross the land bridge because of the lower sea level, Witt Dillon added.

Scientists debate how native dogs generally fall from gene pools: Our ancestors might have killed them to prevent breeding between dogs with dogs that had been raised for hunting and herd, or they could be eaten when hungry.

Disease is the most common cause, because the same thing happens to Native Americans.

In the journal "Science," the researchers argue that the first dogs in America were not cultivated by North American wolves.

Most likely, they wrote, dogs followed companion humans through a land bridge that once connected North Asia through Siberia to America.

At an archaeological site near Cahokia called Janey B. Goode, other researchers found dogs with marks on their shoulders.

Malhi said the signs could mean that the dogs were not only our best friends but our coworkers, helped pull up supply wagons or some other work similar to their continued use of sled in the Northwest.

Malhi's specialty is tracing genetic history, so the article has titles such as "Distribution of Y chromosomes among Native North Americans: a study of the history of the Athapaskan population."

He has worked closely with First Nations nations in British Columbia and Alaska, including studying invaluable food sources, salmon.

Nuclear DNA and mitochondrial DNA tell stories differently.

"DNA is the type of DNA that most people might think of – 23 pairs of your chromosomes are all core DNA, and you inherit half of it from your mother and half from your father," explained Witt Dillon.

"Your mitochondrial DNA is inherited from your mother," he said, "and is found in more cells per copy than your core DNA, making it easier to find in ancient DNA samples, which are usually degraded and fragmented."

There are questions about when and where dogs are tamed.

"Dogs may be tamed between 15,000 and 21,000 years ago, somewhere in Europe or Asia," Witt Dillon said. "Europe, the Middle East, Southeast Asia and Central Asia have all been suggested as places where dogs come from, but we don't have a clear answer yet."

Maybe dogs appear in several "birth" places.

By the way, shit ends every dog ​​walking? It hurts you, but it is very valuable for science as a fossil coprolite.

UI anthropology student Karthik Yarlagadda is looking at microbiomes in coprolites, working with Malhi.

In modern studies, he knew, the samples tested contained a large number of microbes that reflected a number of factors, including genetics, diet and host environment.

"Because coprolytes represent samples of ancient faeces, they probably still contain a certain amount of residual DNA from microbes that lived in dogs at that time. This is very interesting because ancient microbiomes gave us additional insight into the life history of individuals," said Yarlagadda

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