評論
打印
John Hoffecker, an archaeologist at the University of Colorado at Boulder, drew attention to a study of an archaeological site called Bluefish Caves.
博爾德科羅拉多大學的考古學家John Hoffecker對 “藍魚洞”考古遺址非常感興趣。
This is in Yukon, a Canadian territory that abuts Alaska.
遺址位于Yukon，是毗鄰阿拉斯加的一塊加拿大區域。
Some of the remains found in these caves date back 24,000 years.
洞穴中發現的一些遺骸可以追溯到24000年前。
They include stone tools and the bones of horses, caribou and bison, all with marks which imply those bones have been stripped of their flesh by such tools.
這些遺骸包括石器和馬、馴鹿和野牛的骸骨，而這些骸骨上的一些痕跡都表明，骨頭是被這些工具肢解的。
A third line of evidence, a genetic analysis, adds weight to all this.
第三個證據（利用遺傳分析），使所有這一切更有說服力。
It compared 31 modern genomes from the Americas, Siberia and various Pacific islands with 23 ancient genomic sequences from archaeological sites in the Americas.
它將來自美洲，西伯利亞和各太平洋島嶼的31個現代基因組和來自美洲考古遺址的23個古代基因組序列做了比較。
The comparison suggested that Native-American genomes diverged from their Siberian ancestors no earlier than 23,000 years ago.
結果表明，最早是在23000年前，土著美洲基因組與他們的西伯利亞祖先的開始形成區別。
It also showed that the Native-American line was isolated for at least 8,000 years before big genetic splits within it took place as people spread through their new homeland.
這還表明，在人們通過他們的新家園傳播大的遺傳分化之前，美洲線被隔離了至少8000年。
Combining everything, then, it seems that the band of brothers and sisters whose descendants first populated the Americas lived somewhere between 25,000 and 23,000 years ago.
那么結合這一切來看，那些最先定居美洲的后代的祖先，在25000年前到23000年前也可能曾居住在一起，
Very neat, if it were not for the fact that archaeological evidence appears to show that areas outside Alaska and Yukon were colonised rapidly, starting soon after 15,000 years ago.
多虧考古證據的發現，讓我們知道，阿拉斯加和育空附近從15000前開始被迅速的殖民統治。
That could be because the ancestral band and its descendants were confined for much of the intervening period to a region known to palaeogeographers as Beringia.
這可能是因為他們的祖先及其后代在這期間大部分被限制在了一個古地理學家稱為地白令海峽的地方。
This was composed of what are now eastern Siberia, bits of Alaska and Yukon in the Americas, and the Bering Strait between them (which was then dry land).
這是由現在的西伯利亞東部，在美洲阿拉斯加和育空，和白令海峽之間（當時是旱地）組成。
Parts of Beringia were habitable wetlands and grassland steppe.
白令海峽的一些地方是可供居住的濕地和草原。
But the North American ice sheets to its east would have blocked any passage beyond.
但是東部的北美冰蓋隔斷了所有的通道。
That could account for the 8,000 years of genetic autarky in the ancestry of Native Americans,
這可以解釋，印第安人的祖先在8000年里面，遺傳基因的交流都僅限于所居住的地方，
for it was not until the ice sheets retreated (starting about 16,000 years ago), that anyone in Beringia would have been able to pass to the rest of the Americas.
但是從16000年前開始，冰蓋開始慢慢的消失，使得居住在白令海峽的人能夠到達美洲其他地方。
To explain how languages might have continued to diversify in a genetically stable population within Beringia,
DrSicoli認為，語言在白令橋這樣一個基因穩定的地方變得如此多樣化的原因是，
DrSicoli suggests its members may have lived in different habitats, separate enough for linguistic diversification,
在這個地區，人們住的很分散，分散到足以產生多樣化的語音，
but mixing often enough to maintain a single gene pool.
但同時，這些多樣化的語音足以融合形成單一的基因庫。
The answer to the question, “how was America peopled?” seems tantalisingly close.
“美國是如何形成的？” 這一問題，似乎馬上就可以知道答案。
考研英語時事閱讀
