新视野大学英语读写教程听力 第四册 课文 te-07a_new

[-1:-1.00]The genetic maps also shed new light on the origins of populations
[-1:-2.00]that have long puzzled scientists.Example:
[-1:-3.00]the Khoisan people of southern Africa.
[-1:-4.00]Many scientists consider the Khoisan a distinct race of very ancient origin.
[-1:-5.00]The unique character of the clicking sounds in their language
[-1:-6.00]has persuaded some researchers
[-1:-7.00]that the Khoisan people are directly descended from the most primitive human ancestors.
[-1:-8.00]But their genes beg to differ.
[-1:-9.00]They show that the Khoisan may be a very ancient mix of west Asians and black Africans.
[-1:10.00]A genetic trail visible on the maps shows that the breeding ground
[-1:11.00]for this mixed population probably lies in Ethiopia or the Middle East.
[-1:12.00]The most distinctive members of the European branch of the human tree
[-1:13.00]are the Basques of France and Spain.
[-1:14.00]They show unusual patterns for several genes,
[-1:15.00]including the highest rate of a rare blood type.
[-1:16.00]Their language is of unknown origin
[-1:17.00]and cannot be placed within any standard classification.
[-1:18.00]And the fact that they live in a region next to famous caves
[-1:19.00]which contain vivid paintings from Europe's early humans,
[-1:20.00]leads Cavalli-Sforza to the following conclusion:
[-1:21.00]"The Basques are extremely likely to be the most direct relatives
[-1:22.00]of the Cro-Magnon people,
[-1:23.00]among the first modern humans in Europe."
[-1:24.00] All Europeans are thought to be a mixed population,
[-1:25.00]with 65% Asian and 35% African genes.
[-1:26.00]In addition to telling us about our origins,
[-1:27.00]genetic information is also the latest raw material of the medical industry,
[-1:28.00]which hopes to use human DNA to build specialized proteins
[-1:29.00]that may have some value as disease-fighting drugs.
[-1:30.00]Activists for native populations
[-1:31.00]fear that the scientists could exploit these peoples:
[-1:32.00]genetic material taken from blood samples
[-1:33.00]could be used for commercial purposes without adequate payment
[-1:34.00]made to the groups that provide the DNA.
[-1:35.00]Cavalli-Sforza stresses that his mission
[-1:36.00]is not just scientific but social as well.
[-1:37.00]The study's ultimate aim,he says,
[-1:38.00]is to"weaken conventional notions of race"that cause racial prejudice.
[-1:39.00]It is a goal that he hopes will be welcomed among native peoples
[-1:40.00]who have long struggled for the same end.