Study: Ancient Polynesians and South Americans Had Contact

A new study shows that there was mixing between ancient native peoples from Polynesia and South America.

Researchers say they found a single episode of the two groups interbreeding around 800 years ago after a long trip across the Pacific Ocean.

For a long time, the question of such contact had been debated among scientists. The contact was theorized partly because of the presence of a kind of sweet potato in the islands of Polynesia. The plant is native to South and Central America.

Scientists said last week that an examination of DNA¹ from 807 people made the results clear. The genetic² material came from 14 Polynesian islands and Pacific coastal³ Native American populations from Mexico to Chile.

People from four island areas in French Polynesia had DNA that showed interbreeding with South Americans at around the year 1200. Those South Americans were most closely related to present-day native Colombians.

The islands are about 6,800 kilometers from South America.

People from Easter Island also had South American ancestry⁴, some from modern Chilean immigrants and some from the same ancient mixing as the other islands.

Easter Island, which belongs to Chile, was settled sometime after the interbreeding 800 years ago. The island, which lies 3,700 kilometers west of South America, is known for its massive stone statues.

The study left open the question of who crossed the Pacific Ocean. Were Polynesians traveling east and arriving in Colombia or maybe Ecuador? Or were South Americans traveling west?

Alexander Ioannidis is a computational geneticist at Stanford University in California. He was the lead author of the research, which appears in the science journal Nature.

Ioannadis says he thinks the Polynesians crossed the Pacific, since they were "exploring the ocean and discovering some of the most distant Pacific islands around exactly the time of contact." The Reuters news agency reported his comments.

If the Polynesians reached the Americas, he added, they probably traveled in sailing canoes with two hulls⁵. He noted⁷ these boats operate much like a modern catamaran, another kind of two-hulled boat.

The contact explains the mystery of how the sweet potato arrived in Polynesia centuries before European sailors. Ioannidis noted the vegetable's name in many Polynesian languages - kumara - sounds similar to its name in some languages spoken in the Andes Mountains.

I'm Alice Bryant.

Words in This Story

episode - n. an event or a short period of time that is important or unusual

interbreed - v. to breed or cause to breed with another of a different race or species

theorize - v. to think of or suggest ideas about what is possibly true or real : to form or suggest a theory about something

DNA - n. a substance that carries genetic information in the cells of plants and animals — often used before another noun

author - n. a person who has written something

hull⁶ - n. the main body of a boat or ship, including the bottom, sides, and deck but not the masts and other parts

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 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。

3 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

4 ancestry   

n.祖先，家世

参考例句：

• Their ancestry settled the land in 1856.他们的祖辈1856年在这块土地上定居下来。
• He is an American of French ancestry.他是法国血统的美国人。

5 hulls   

船体( hull的名词复数 )； 船身； 外壳； 豆荚

参考例句：

• Hulls may be removed by aspiration on screens. 脱下的种皮，可由筛子上的气吸装置吸除。
• When their object is attained they fall off like empty hulls from the kernel. 当他们的目的达到以后，他们便凋谢零落，就象脱却果实的空壳一样。

6 hull   

n.船身；(果、实等的)外壳；vt.去(谷物等)壳

参考例句：

• The outer surface of ship's hull is very hard.船体的外表面非常坚硬。
• The boat's hull has been staved in by the tremendous seas.小船壳让巨浪打穿了。

7 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。