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VI. Reading Comprehension (12%；2% for each)             Ancient Infant’s DNA Provides Key to Native American Ancestry                                                                                                                              By Sarah Pruitt                   Between 13,000 and 12,600 years ago, members of the Clovis culture appeared in NorthAmerica, where they made and used distinctive stone-tipped spears to hunt mammoth, bison andmastodon. Until recently, all that archeologists knew about the Clovis people came from studyingtheir tools, which have been unearthed at wide-ranging sites across the country. Now, DNA analysisof a single human skeleton—that of a one-year-old boy buried in a rocky field in modern-dayMontana—has allowed scientists to link the Clovis culture to Native Americans throughout theWestern Hemisphere.            Construction crews first discovered the ancient remains of an infant in 1968 on private propertyowned by the Anzick family in western Montana. Dubbed Anzick-1, the one-year-old boy is the onlyhuman skeleton that has been identified as a member of the widespread, sophisticated Ice-Age cultureknown as Clovis. Now, a team of scientists has succeeded in mapping the infant’s DNA, in the oldestgenome sequence of an American individual ever performed. According to their findings, publishedin the journal Nature in February 2014, the Clovis people are direct ancestors of many NativeAmericans now living in North America, and can be linked to many native peoples in Central andSouth America as well.        Up to this point, all scientists studying the Clovis culture had to go on with the stone and bonetools that have been found at sites ranging from Washington State to Florida, along with many states5in between. By sequencing the genome of the infant recovered at the Anzick site, the internationalteam of researchers gained the most vivid insight yet about who these people might actually havebeen. They compared the DNA of the Clovis infant to several different genomes, including a24,000-year-old sample from a young man buried on the banks of Lake Baikal in Siberia, a7,000-year-old sample from Spain and a 4,000-year-old sample from Greenland. The Clovis DNAshowed the most similarity with that of the Siberian youth, whom scientists genetically linked withtoday’s Native Americans in 2013.     The new study adds to existing archeological evidence that Native Americans descended fromhumans who migrated to North America from Asia through Siberia around 15,000 years ago. Theyare believed to have made the voyage across the Bering land bridge, which connected Asia withNorth America during the last Ice Age. According to archeologist Michael Waters of Texas A&MUniversity, a member of the team who conducted the new study, the genetic evidence “stronglysuggests that there was a single migration of people into the Americas….These people were probablythe people who eventually gave rise to Clovis.”     Such evidence casts doubt on other theories arguing that Clovis’ ancestors came from Europe,rather than Asia. Such hypotheses rely partially on the fact that the “Clovis points” found on theirtools and weapons are so similar to the flint tools used by the Solutrean culture, which flourished inSpain and France during the Ice Age.     While Anzick-1 showed the most genetic similarities with Native Americans in North America,the study also revealed ties with the indigenous peoples of Central and South America. The team’sdata indicates that sometime between 13,000 and 24,000 years ago, the same ancient people thatarrived from Asia split into two lineages: One gave rise to Clovis and today’s Native Americans ofNorth America, and the other became the ancestors of Central and South American tribes.       The scientists studying Anzick-1 have worked closely with Native American tribes in Montana,sharing the results of the study with them and ensuring that the remains were treated appropriately.The infant will be reburied later this year, on the same property from which he was unearthed. Fortheir part, the tribes have shown little surprise at the scientists’ conclusions. Shane Doyle, a professorof Native American History at Montana State University and co-author on the study, is also a memberof the Crow tribe. As he told NBC News, after conversations with more than 100 tribe members, themain reaction was “We have no reason to doubt that we’ve been here for this long.”
35. The text describes a possible sequence of human descent. At the end of the sequence are NativeAmericans. What people are at the beginning of the sequence?
(A) people who migrated from Asia to North America about 15,000 years ago6
(B) tribes living in Central and South America today
(C) people who were living in Greenland about 4,000 years ago[!--empirenews.page--]
(D) people who were living in Spain about 7,000 years ago

參考答案

答案：A
難度：適中0.5
統計：A(0),B(0),C(0),D(0),E(0)

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