Human evolution
20. Before the exodus (The Economist Apr 24th 2008)

20-1-95
For two-thirds of its history, Homo sapiens lived exclusively in Africa. Only now are the details of that period becoming clear

MITOCHONDRIAL DNA is a remarkable thing. Itself the remnant of a strange evolutionary event (the merger of an ancient bacterium with the cell ancestral to all plant and animal life), it also carries the imprint of more recent evolution. In many species, humans included, it passes only from mother to child. No paternal genes get mixed into it. That makes it easy to see when particular genetic mutations happened, and thus to construct a human family tree.
The branches of that tree are now well studied. Humans started in Africa, spread to Asia around 60,000 years ago, thence to Australia 50,000 years ago, Europe 35,000 years ago and America 15,000 years ago. What have not been so well examined, though, are the tree's African roots. The genetic diversity of Africans probably exceeds that of the rest of the world put together. But the way that diversity evolved is unclear.

A. 어휘
evolution 進化(진화). exodus 출국, 移住(이주). exclusively 배타적으로, 주로.
detail 細部(세부), 상세한 것. remarkable 주목할 만한, 두드러진.
remnant 나머지, 殘存(잔존), 단편, 자투리. merger 合倂(합병).
the cell ancestral 조상이 되는 세포. imprint 흔적, 자국.
humans included 인간을 포함해서. paternal 아버지 쪽의. mutation 돌연변이, 변화.
construct 조립하다, 구축하다. branch 나무 가지. examine 점검하다.
diversity 다양성. exceed 능가하다. evolve 진화하다.

B. 구문
-The genetic diversity . . . the world put together.
cf. that→ the genetic diversity
. the rest of the world put together →the rest of the world which is put together
[ 아프리카인들의 유전적 다양성은 전 세계의 나머지를 합친 것을 능가한다.]

20-2-96
A study carried out under the auspices of the Genographic Project, based in Washington, DC, and just published in the American Journal of Human Genetics, goes some way towards correcting this oversight. The study's researchers, led by Doron Behar of the Rambam Medical Centre in Haifa and Spencer Wells of America's National Geographic Society, have used the mitochondrial DNA of more than 600 living Africans to show how genetic diversity has developed in Africa. In doing so, they have shed light on how modern man spread around his home continent long before he took the first, tentative steps into a bigger, wider world.

By the drought divided
The team paid particular attention to samples taken from the Khoi and San people of southern Africa. These people, known colloquially as bushmen, traditionally make their livings by hunting and gathering. Indeed, their way of life is thought by many anthropologists to resemble quite closely that of pre-agricultural people throughout the world.
Comparing Khoi and San DNA with that of other Africans shows that the first big split in Homo sapiens happened shortly after the species emerged, 200,000 years ago. Most people now alive are on one side of that split. Most bushmen are on the other. The consortium's analysis of which DNA “matrilines” are found where suggests that for much of its history the species was divided into two isolated populations, one in eastern Africa and one in the south of the continent, that were defined by this split. However, few other matrilineal splits from the first 100,000 years of the species's history have survived to the present day.

A. 어휘
auspices 찬조, 후원, 보호. genographic 유전지도. genetics 유전학.
correct 교정하다. oversight 간과, 빠뜨림. shed-shed-shed (눈물을) 흘리다, 발산하다.
shed light 밝히다. tentative 시험(실험)적인, 일시적인. drought 가뭄, 旱魃(한발).
colloquially 口語體(구어체)로. anthropologist 인류학자. resemble 닮다.
pre-agricultural 농업시대 이전의. split 分化(분화), 쪼개짐. species 種(종).
emerge 출현하다. consortium 합작, 연합, 제휴. analysis 분석. matriline 母系(모계).
isolated 격리된, 고립된.

B. 구문
-The consortium' analysis . . . found where.
[ 어느 母系(모계) DNA가 어디에서 발견되는가에 대한 그 컨소시엄( Doron Behar와 Spencer Wells의 합동연구)의 분석.]
-the species was divided . . . defined by this split.
[ 그 種(인류)은 이 分化에 의해서 定意(정의)되는 두 개의 고립된 人間의 群(군), 즉 동아프리카의 사람들과 남아프리카의 사람들로 갈라졌다.]

20-3-97
This suggests the early human population was tiny (so the opportunities for new matrilines to evolve in the first place were limited) and reinforces the idea that Homo sapiens may have come close to extinction (eliminating some matrilines that did previously exist). Indeed, there may, at one point, have been as few as 2,000 people left to carry humanity forward.
This shrinkage coincides with a period of prolonged drought in eastern Africa, and was probably caused by it. The end of the drought, however, was followed by the appearance of many new matrilines that survive to the present day. The researchers estimate that by 60,000-70,000 years ago, the period when the exodus that populated the rest of the world happened, as many as 40 such groups were flourishing in Africa-though that migration involved only two of these groups.
The African matrilines, however, seem to have remained isolated from each other for tens of millennia after the exodus. It was not until 40,000 years ago that they began to re-establish conjugal relations, possibly as a result of the technological revolution of the Late Stone Age, which yielded new and more finely crafted tools. Only the bushmen seem to have missed out on this panmictic party. They were left alone until a few hundred years ago, when their homelands were invaded from the north by other Africans and from the south by Europeans. Panmixis thus came full circle. And that particular party was certainly not a happy one.

A. 어휘
tiny 아주 작은. reinforce 강화하다. extinction 絶滅(절멸). eliminate 제거하다.
previously 이전에. humanity 인류. shrinkage 축소. coincide 일치하다.
drought 가뭄. estimate 평가하다. flourish 繁盛(번성)하다. migration 移住(이주).
conjugal 혼인의, 부부의. yield 생산하다. finely 精巧(정교)하게. craft 기술, 공예.
more finely crafted tools 보다 더 정교하게 제작된 도구들. cf. crafted 형용사로 쓰인 과거분사. miss out 漏落(누락)되다.
panmictic: unstructured(random-mating) populations[짝짓기가 무제한적으로 이루어지는 인구집단]. panmictic party 인종에 제한 없이 결혼(혼혈)이루어지는 짝짓기 파티.
invade 침공하다. panmixis 雜婚(잡혼).

B. 구문
- the period when . . . the world happened.
[ 세계의 나머지 지역에 사람들이 살게 된 결과를 가져온 인구이동이 일어난 시기]
-It was not until . . . conjugal relations.
cf. it is not until . . . that 구문.
ex. He did not come home until late at night.
→Not until late at night did he come home. (도치구문)
→It was not until late at night that he came home.(it is . . . that 강조구문).
[ 40,000년 전에 비로소 인간들은 (母系 DNA가 혼합되는)혼인관계를 재확립하였다.]