(과학) 유럽인들 고대 3개 부족에서 유래

출처: http://www.bbc.com/news/science-environment-29213892

17 September 2014 Last updated at 17:46

Europeans drawn from three ancient 'tribes' 유럽인들 고대의 세 '부족'에서 유래

By Paul RinconScience editor, BBC News website

The modern European gene pool was formed when three ancient populations mixed within the last 7,000 years, Nature journal reports. 현대 유럽인의 유전자 공급원은 7천년 이내 세 부류의 고대인들이 섞여서 형성된 것이라고, 네이쳐紙는 전한다.

Blue-eyed, swarthy hunters mingled with brown-eyed, pale skinned farmers as the latter swept into Europe from the Near East. (3부족이란) (1)파란 눈(의 부족), (2) 갈색눈과 섞인 거무스름한 사냥꾼들, (3)근동에서 유럽으로 건너온 흰피부의 농부들

But another, mysterious population with Siberian affinities also contributed to the genetic landscape of the continent.

The findings are based on analysis of genomes from nine ancient Europeans. 이런 결과물은 9명의 고대 유럽인들의 게놈을 분석한 바에 근거하고 있다.

Agriculture originated in the Near East - in modern Syria, Iraq and Israel - before expanding into Europe around 7,500 years ago. 농업은 현재의 시리아, 이라크, 이스라엘에 해당하는 근동에서 유래하였으며, 약 7,500년전 유럽으로 확대되기 전이다.

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It really does look like the indigenous West European hunter gatherers had this striking combination of dark skin and blue eyes that doesn't exist any more”

Prof David ReichHarvard Medical School

Multiple lines of evidence suggested this new way of life was spread by a wave of migrants, who interbred with the indigenous European hunter-gatherers they encountered on the way. 여러 증거들을 보면, 이런 새로운 방식의 삶은 많은 이주자들에 의해 전파되었다. 이들은 이동 중에 만난  수렵인인 토작 유럽인들과 피를 섞었(이종교배하였)다.

But assumptions about European origins were based largely on the genetic patterns of living people. The science of analysing genomic DNA from ancient bones has put some of the prevailing theories to the test, throwing up a few surprises. 그러나 유럽인에 대한 가정은 대개 살아있는 사람들의 유전적 패턴에 근거하였다. 고대인의 뼈에서 게놈 DNA를 분석하는 학문은 놀라움을 주면서, 잘 나가는 이론들을 시험하고 있다.

Genomic DNA contains the biochemical instructions for building a human, and resides within the nuclei of our cells. 게놈의 DNA에는 사람을 구성하는 생화학적인 것들 포함하고 있으며, 세포의 핵 내부에 존재한다.

In the new paper, Prof David Reich from the Harvard Medical School and colleagues studied the genomes of seven hunter-gatherers from Scandinavia, one hunter whose remains were found in a cave in Luxembourg and an early farmer from Stuttgart, Germany. 새로운 연구 논문에서, 하바드 대학교 의과대학 데이빗 레이크 교수와 동료 연구진들은 스칸디나비아의 수렵인 7명 과 룩셈부르그 동굴에서 발견된 수렵인 1명과 독일 스투트가르트의 농부 1명을 연구했다.

The hunters arrived in Europe thousands of years before the advent of agriculture, hunkered down in southern refuges during the Ice Age and then expanded during a period called the Mesolithic, after the ice sheets had retreated from central and northern Europe. 수렵인들은 농업의 발생 수천년 전에 유럽에 들어와, 빙하기 동안 남쪽 피난처에 정착한 다음, 중남부 유럽에서 빙하가 물러간 뒤,중석기시대 동안 퍼져나갔다. 

Their genetic profile is not a good match for any modern group of people, suggesting they were caught up in the farming wave of advance. 이들의 유전적 특성은 현대인들과 잘 매치가 안 된다. 왜냐하면 그들은 발전된 농업에 국한되었기 때문이다.

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If you look at all the reconstructions of Mesolithic people on the internet, they are always depicted as fair skinned... This shows the opposite”

Prof Carles Lalueza-FoxInstitute of Evolutionary Biology (CSIC - UPF)

However, their genes live on in modern Europeans, to a greater extent in the north-east than in the south. 그러나 이들의 유전자는 유럽의 현대 유럽인들 안에, 대체로 남쪽보다는 북동쪽에 사는 사람들 안에 면면이 살아있다.

The early farmer genome showed a completely different pattern, however. Her genetic profile was a good match for modern people in Sardinia, and was rather different from the indigenous hunters. 그러나 초기 (여성)농부의 게놈은 완전히 다른 패턴을 보였주었다. 그녀의 유전적 특성은 스칸디나비아에 사는 현대인들과 좋은 매치가 되었으며, 토착 수렵인들과 다른 양상을 보여주었다.

But, puzzlingly, while the early farmers share genetic similarities with Near Eastern people at a global level, they are significantly different in other ways. Prof Reich suggests that more recent migrations in the farmers' "homeland" may have diluted their genetic signal in that region today.ㅂㅇ

Prof Reich explained: "The only way we'll be able to prove this is by getting ancient DNA samples along the potential trail from the Near East to Europe... and seeing if they genetically match these predictions or if they're different.

"Maybe they're different - that would be extremely interesting."

The agricultural transition was a period of momentous cultural and demographic change 농업으로 전환은 순간적인 문화적 인구학적 변화의 시기이다 

Pigmentation genes carried by the hunters and farmers showed that, while the dark hair, brown eyes and pale skin of the early farmer would look familiar to us, the hunter-gatherers would stand out if we saw them on a street today.

"It really does look like the indigenous West European hunter gatherers had this striking combination of dark skin and blue eyes that doesn't exist any more," Prof Reich told BBC News.

Dr Carles Lalueza-Fox, from the Institute of Evolutionary Biology (CSIC - UPF) in Barcelona, Spain, who was not involved with the research, told BBC News: "If you look at all the reconstructions of Mesolithic people on the internet, they are always depicted as fair skinned. And the farmers are sometimes depicted as dark-skinned newcomers to Europe. This shows the opposite."

So where did fair pigmentation in present-day Europeans come from? The farmer seems to be on her way there, carrying a gene variant for light skin that's still around today.

"There's an evolutionary argument about this - that light skin in Europe is biologically advantageous for people who farm, because you need to make vitamin D," said David Reich.

"Hunters and gatherers get vitamin D through their food - because animals have a lot of it. But once you're farming, you don't get a lot of it, and once you switch to agriculture, there's strong natural selection to lighten your skin so that when it's hit by sunlight you can synthesise vitamin D."

This reconstruction shows the dark skin and blue eyes of a 7,000-year-old hunter from northern Spain 이 재구성은 북 스페인에서 살았던 7천년 된 사냥꾼의 거무틱틱한 피부와 파란 눈을 보여준다

When the researchers looked at DNA from 2,345 present day people, they found that a third population was needed to capture the genetic complexity of modern Europeans.

This additional "tribe" is the most enigmatic and, surprisingly, is related to Native Americans.

Hints of this group surfaced in an analysis of European genomes two years ago. Dubbed Ancient North Eurasians, this group remained a "ghost population" until 2013, when scientists published the genome of a 24,000-year-old boy buried near Lake Baikal in Siberia.

This individual had genetic similarities to both Europeans and indigenous Americans, suggesting he was part of a population that contributed to movements into the New World 15,000 years ago and Europe at a later date.

The ancient hunter from Luxembourg and the farmer from Germany show no signs of mixture from this population, implying this third ancestor was added to the continental mix after farming was already established in Europe.

The study also revealed that the early farmers and their European descendents can trace a large part of their ancestry to a previously unknown, even older lineage called Basal Eurasians. This group represents the earliest known population divergence among the humans who left Africa 60,000 years ago.