VOA科学技术2024--Where Did Modern Humans Go after Africa?

Where Did Modern Humans Go after Africa?

　　A new study offers an answer to the question of where early humans traveled after leaving Africa.

　　Scientists say modern humans, or Homo sapiens, developed in Africa more than 300,000 years ago. Early humans then left Africa between 60,000 to 70,000 years ago.

　　Researchers said in a recently released study that these groups of hunter-gatherers appear to have stayed for thousands of years in an area of the Middle East. That area includes modern-day Iran, southeastern Iraq and northeastern Saudi Arabia. The early humans went on to settle all of Asia and Europe starting about 45,000 years ago.

　　The scientists based their findings on genomic data taken from ancient DNA¹ and from the genes² of modern people. Scientists combined that data with paleoecological evidence. That is ancient evidence that suggests what the environment in these areas would have been like long ago.

　　The evidence suggested the area in the Middle East would have been good for early humans. The researchers called this area a "hub" for these early people before they continued to more distant places. At the time, they numbered perhaps only in the thousands.

　　The study was published in the scientific journal Nature Communications. Michael Petraglia is an anthropologist³ and a study co-author. He said the study "is a story about us and our history - our goal was to unravel⁴ some of the mystery about our evolution and our worldwide dispersal."

　　"The combination of genetic⁵ and paleoecological models allowed us to predict the location where early human populations first" lived as soon as they left Africa, Petraglia added.

　　These people lived in small groups of hunter-gatherers, the researchers said. The hub location offered several environmental settings, from forests to grasslands⁶, changing over time between dry and wet periods.

　　There would have been many resources available, with evidence showing the hunting of wild gazelle, sheep and goat, Petraglia said.

　　They would have eaten "plants and small- to large-sized game. Hunter-gatherer groups seemed to have practiced a seasonal⁷ lifestyle, living in the lowlands in the cooler months and in the mountainous regions in the warmer months," Petraglia said.

　　The people living in the hub at the time had dark skin and dark hair. Many might have looked like the Gumuz or Anuak people now living in parts of East Africa, said Luca Pagani, one of the study's writers.

　　Later, they dispersed⁹ in different directions beyond the hub and the genetic differences developed between present-day East Asians and Europeans, the researchers said.

　　The study used modern and ancient genomic data for European and Asian people. The researchers found a way to disentangle the extensive genetic mixing of populations that has taken place since then.

　　There were earlier smaller dispersals of Homo sapiens out of Africa before the most important migration¹⁰ 60,000 to 70,000 years ago. But the study said these appear to have been dead ends, meaning they produced nothing.

　　Homo sapiens was not the first human species to live outside of Africa - including the area surrounding the hub. Ancient intermixing by modern humans has left small traces of Neanderthal in the DNA of modern non-Africans.

　　The lead writer of the study, Leonardo Vallini, said there is evidence Neanderthals lived in the area "before the arrival of Homo sapiens, so the hub may well have been where that interaction took place."

　　Homo sapiens is the scientific name for today's humans. It means "wise man."

　　Words in This Story

　　genome — n. the genetic material possessed¹¹ by a living thing

　　paleoecological — adj. related to an ancient environment

　　unravel — v. to take apart; to show hidden parts of something

　　evolution — n. the development and change of living things that takes place over a long period

　　disperse⁸ — v. to spread out over a wide area

　　allow — v. to permit or let happen

　　location –n. the place where something is

　　game — n. animals that are normally hunted for food or sport

　　disentangle — v. to order what is disordered and hard to understand

　　dead-end — n. a place with no outlet; something that produces nothing

1 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

2 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

3 anthropologist   

n.人类学家，人类学者

参考例句：

• The lecturer is an anthropologist.这位讲师是人类学家。
• The anthropologist unearthed the skull of an ancient human at the site.人类学家在这个遗址挖掘出那块古人类的颅骨。

4 unravel   

v.弄清楚（秘密）；拆开，解开，松开

参考例句：

• He was good with his hands and could unravel a knot or untangle yarn that others wouldn't even attempt.他的手很灵巧，其他人甚至都不敢尝试的一些难解的绳结或缠在一起的纱线，他都能解开。
• This is the attitude that led him to unravel a mystery that long puzzled Chinese historians.正是这种态度使他解决了长期以来使中国历史学家们大惑不解的谜。

5 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

6 grasslands   

n.草原，牧场( grassland的名词复数 )

参考例句：

• Songs were heard ringing loud and clear over the grasslands. 草原上扬起清亮激越的歌声。 来自《现代汉英综合大词典》
• Grasslands have been broken and planted to wheat. 草原已经开垦出来，种上了小麦。 来自《简明英汉词典》

7 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。

8 disperse   

vi.使分散；使消失；vt.分散；驱散

参考例句：

• The cattle were swinging their tails to disperse the flies.那些牛甩动着尾巴驱赶苍蝇。
• The children disperse for the holidays.孩子们放假了。

9 dispersed   

adj. 被驱散的, 被分散的, 散布的

参考例句：

• The clouds dispersed themselves. 云散了。
• After school the children dispersed to their homes. 放学后，孩子们四散回家了。

10 migration   

n.迁移，移居，（鸟类等的）迁徙

参考例句：

• Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
• He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。

11 possessed   

adj.疯狂的；拥有的，占有的

参考例句：

• He flew out of the room like a man possessed.他像着了魔似地猛然冲出房门。
• He behaved like someone possessed.他行为举止像是魔怔了。