Scientists study genomes to find origins of early farmers


The first farmers came from the mixture of two groups of hunter-gatherers brought together by a dramatic climate change 12,900 years ago, according to a study.

Researchers have uncovered a wealth of new genetic information extracted from previously discovered bones of ancient humans.

The results suggest that the world’s first farmers did not originate from a single group in Asia, as previously thought, before spreading west into Europe.

In fact, the first farmers were descendants of hunter-gatherers from Europe and the Near East, the researchers say.

European hunter-gatherers had headed east after the Last Glacial Maximum, a major climatic event where temperatures plummeted 20,000 years ago.

When they reached the east, these European hunter-gatherers then mated with hunter-gatherers from the Near East.

Eventually, their descendants (who became the first farmers) moved west, essentially marking the spread of agriculture in Europe.

The first farmers were the descendants of hunter-gatherers from Europe and the Near East. These hunter-gatherers from Europe moved east because of the Last Glacial Maximum and then bred with Asian populations in Asia. Their descendants (early farmers) headed west – marking the spread of agriculture in Europe

Humans evolved from a hunter-gatherer lifestyle (consisting of killing animals and foraging for plants) to an agricultural lifestyle (where they planted crops and settled in one place).  Represented are some of the first European farmers

Humans evolved from a hunter-gatherer lifestyle (consisting of killing animals and foraging for plants) to an agricultural lifestyle (where they planted crops and settled in one place). Represented are some of the first European farmers

THE LAST FREEZING MAXIMUM

About 20,000 years ago, a major climatic event called the Last Glacial Maximum caused a drop in global temperature.

During the Last Glacial Maximum, the continental ice sheets reached their maximum total mass, while the land near the ice sheets that escaped glaciation was cold and covered in tundra vegetation.

Due to the drop in temperature, a group of hunter-gatherers in the west experienced an extreme reduction in population, where some came close to extinction.

“We now see that the first farmers in Anatolia and Europe emerged from a mixed population of hunter-gatherers from Europe and the Near East,” said study author Nina Marchi of the University of Bern.

It is already known that the first agriculture occurred in the so-called Fertile Crescent, a region of the Near East around 11,000 years ago.

At this point, people began to domesticate animals and plants in a sedentary place, rather than constantly moving around in search of food.

Agriculture gradually spread westward from Asia across Europe, beginning around 9,000 years ago in Greece.

Regions further west, such as Britain, were untouched for another 2,000 years and Scandinavia even later.

Genetic analyzes of prehistoric skeletons have also previously suggested that early European farmers descended from hunter-gatherer populations in Anatolia, the large peninsula of western Asia.

While this may well be the case, this new study shows that Neolithic genetic origins cannot be clearly attributed to a single region.

Researcher analyzing ancient human remains for paleogenetic research at Johannes Gutenberg University in Mainz, Germany

Researcher analyzing ancient human remains for paleogenetic research at Johannes Gutenberg University in Mainz, Germany

Researchers have uncovered a wealth of new genetic information extracted from previously discovered bones of ancient humans.  Pictured is individual 'Klein7' from the Kleinhadersdorf site in Lower Austria's Weinviertel, whose genome was analyzed in the article

Researchers have uncovered a wealth of new genetic information extracted from previously discovered bones of ancient humans. Pictured is individual ‘Klein7’ from the Kleinhadersdorf site in Lower Austria’s Weinviertel, whose genome was analyzed in the article

AGRICULTURE MADE OUR ANCESTORS SHORTER, STUDY SAYS

Our ancestors became shorter when they switched from foraging to farming 12,000 years ago, according to a new study.

Researchers analyzed DNA and took measurements from the skeletal remains of 167 ancient individuals found across Europe.

The bones had already been dated before, after or around the time when agriculture appeared in Europe 12,000 years ago.

The shift from a hunter-gatherer lifestyle to farming crops has reduced their height by an average of 1.5 inches, experts have found.

A shorter waist is an indicator of poor health, they say, because it suggests they weren’t getting enough nutrition to support adequate growth.

Read more: Farming shortened our ancestors, study finds

For their study, the researchers analyzed bone genomes, taken from the skeletons of ancient people from a wide range of locations, including Anatolia, Greece, Serbia, Austria and Germany.

The researchers used a technique called deep sequencing, where each ancient human’s genome was sequenced multiple times.

This yielded higher quality data and significantly more information than conventional analyzes based on shallower or partial sequencing.

“We’re getting a lot more detail about the demographic history of these populations, including population divergence, expansions and mixing dates, which was really impossible to do before,” the study author said. Laurent Excoffier from the University of Bern, Switzerland.

The model was then refined by additional geographic, cultural, archaeological and climatic data.

The findings suggest that early farmers represented a mix of Ice Age hunter-gatherer groups spread from the Near East to southeastern Europe.

Some of the earliest farmers were born from the mixing of hunter-gatherers from a western group and an already mixed group living in the east around 12,900 years ago.

These farmers who domesticated plants and animals then migrated west, eventually bringing their culture to central Europe.

Today, many people from all over Europe have come from it.

Location of archaeological sites with newly sequenced genomes and additional genomes used for modeling

Location of archaeological sites with newly sequenced genomes and additional genomes used for modeling

There was also evidence that western European hunter-gatherers went through a period of extremely low population size during the Last Glacial Maximum.

The descendants of European hunter-gatherers show lower diversity than the first farmers because their ancestors went through a very strong demographic bottleneck during which they lost a lot of diversity.

Going forward, the team plans to further analyze ancient genomes from other geographic locations and time periods to understand cultures and populations that arose at different stages of the Stone Age and potentially the Bronze Age. .

“While our study provided new insights into history, I think what it really shows is that it is worth investing in high-quality genomic data,” Excoffier said.

“These ancient materials are limited and too valuable not to be analyzed optimally. We should extract as much information as possible, which will become enduring resources that can be shared.

The study was published today in the journal Cell.

BRITAIN DURING THE LAST ICE AGE

The last glacial maximum was around 22,000 years ago, when much of Europe was covered in ice.

During the Ice Age, which ended about 11,500 years ago, ice covered about 30% of the world’s land.

In Britain, glacial ice and water flows have spread as far south as the Bristol Channel.

Average temperatures were 5°C (8°F) colder than they are today, allowing a mile-thick layer of ice to cover much of the country.

The temperature remained below 0°C all year round in the northern regions, particularly in Scotland, allowing the leaf to remain on the land all year round.

The ice connected Britain to Scandinavia, allowing a multitude of wildlife to move freely between the UK and mainland Europe.

During this period, Britain is said to have seen woolly mammoths, giant stags and wolves roam its icy planes.

Large glacial lakes covered Manchester, Doncaster, Newcastle and Peterborough and much of the country was uninhabitable for humans.

Fast-flowing corridors of ice, known as Ice Streams, flowed east over Edinburgh and west of Glasgow.

All of Ireland was covered in ice, which crossed the Irish Sea where it met the Welsh ice, then flowed south towards the Isles of Scilly.

Much of Scotland, Wales, the Midlands and northern England was covered in perpetual ice.

Cambridge, which was covered by a huge glacial lake, was the southernmost region to be heavily affected by the frigid climate.

Over time, the ice and its abundant water flows carved into the land of Britain, forming geological scars that can still be seen today.

These include glacial ridges carved by moving ice and winding rock flows that have traveled for miles across the country.

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