科学家发现决定鼠类肤色的基因
文章来源:未知 文章作者:enread 发布时间:2011-02-25 03:31 字体: [ ]  进入论坛
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Scientists at Harvard University are moving closer to answering some age-old questions. How did the leopard1 get its spots? How did the zebra get its stripes?

The answer may be a gene2 called Agouti, which the Harvard team has found governs color patterns in deer mice, the most widespread mammal in North America. This gene, found in all vertebrates(脊椎动物) , may establish color pattern in a wide variety of species, a process that has been poorly understood at both the molecular3 and the evolutionary4 level.

"The question of how color patterns are established in vertebrates has been a black box," says Marie Manceau, a research associate in Harvard's Department of Organismic and Evolutionary Biology and lead author of a paper appearing this week in the journal Science. "Taking advantage of the simple color pattern of deer mice -- which have a dark back and a light belly5 -- we showed that small changes in the activity of a single pigmentation(染色) gene in embryos7 generate big differences in adult color pattern."

Manceau and senior author Hopi E. Hoekstra found that color patterns in these mice rely on the establishment of an embryonic8 "pre-pattern" of Agouti expression. In the mice they studied, this took place midway through gestation9 -- just 12 days after conception, well before the first pigments10 are ever produced in the skin.

Agouti had previously11 been known to affect the type of pigment6 found in vertebrate fur, feathers, and scales: Little expression of the gene in adults results in the production of dark pigments, while robust12 Agouti activity generally yields light pigment production. But Manceau and Hoekstra found that subtle changes in the gene's embryonic activity can also make a profound difference in the distribution of pigments across the entire body.

"During embryogenesis, Agouti is expressed in the belly, where it delays maturation of the cells that will eventually produce pigments," says Hoekstra, John L. Loeb Associate Professor of the Natural Sciences at Harvard. "This leads to a lighter13 colored belly in adults, which is the most common color pattern across a wide variety of vertebrates, from fish to antelope14(羚羊) ."

Beyond color patterning, this study highlights how genetic15 and developmental mechanisms16 underlying17 trait variation can affect the evolution of natural diversity: Even small changes in Agouti gene expression can establish a completely new color pattern. In deer mice, natural selection drives changes in the amount and place of Agouti expression, which in turn results in new color patterns that can camouflage18(伪装,掩饰) animals from visual predators19 in habitats including dark forests and light sandy beaches.

"It is hard not to speculate that Agouti plays a role in generating more complex patterns -- from stripes to spots -- in a diversity of vertebrates," Hoekstra says.

Manceau and Hoekstra now plan to continue researching the molecular basis of animals with more complex color patterns, such as zebra mice, chipmunks20(金花鼠) , thirteen-lined ground squirrels, and perhaps eventually even leopards21 and zebras.

"Are the same pre-patterning mechanisms we see in deer mice also involved in the formation and evolution of more complex pigment patterns, like the racing22 stripes of chipmunks?" Manceau asks. "That's the exciting question now."



点击收听单词发音收听单词发音  

1 leopard n9xzO     
n.豹
参考例句:
  • I saw a man in a leopard skin yesterday.我昨天看见一个穿着豹皮的男人。
  • The leopard's skin is marked with black spots.豹皮上有黑色斑点。
2 gene WgKxx     
n.遗传因子,基因
参考例句:
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
3 molecular mE9xh     
adj.分子的;克分子的
参考例句:
  • The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
  • For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时,分子的碰撞就停止了。
4 evolutionary Ctqz7m     
adj.进化的;演化的,演变的;[生]进化论的
参考例句:
  • Life has its own evolutionary process.生命有其自身的进化过程。
  • These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
5 belly QyKzLi     
n.肚子,腹部;(像肚子一样)鼓起的部分,膛
参考例句:
  • The boss has a large belly.老板大腹便便。
  • His eyes are bigger than his belly.他眼馋肚饱。
6 pigment gi0yg     
n.天然色素,干粉颜料
参考例句:
  • The Romans used natural pigments on their fabrics and walls.古罗马人在织物和墙壁上使用天然颜料。
  • Who thought he might know what the skin pigment phenomenon meant.他自认为可能知道皮肤色素出现这种现象到底是怎么回事。
7 embryos 0e62a67414ef42288b74539e591aa30a     
n.晶胚;胚,胚胎( embryo的名词复数 )
参考例句:
  • Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物体细胞进入一个生殖阶段,而且其行为象胚。 来自辞典例句
  • Evolution can explain why human embryos look like gilled fishes. 进化论能够解释为什么人类的胚胎看起来象除去了内脏的鱼一样。 来自辞典例句
8 embryonic 58EyK     
adj.胚胎的
参考例句:
  • It is still in an embryonic stage.它还处于萌芽阶段。
  • The plan,as yet,only exists in embryonic form.这个计划迄今为止还只是在酝酿之中。
9 gestation L6ey2     
n.怀孕;酝酿
参考例句:
  • The gestation period can be anything between 95 and 150 days.妊娠期从95天至150天不等。
  • This film was two years in gestation.这部电影酝酿了两年。
10 pigments 90c719a2ef7a786d9af119297e63a36f     
n.(粉状)颜料( pigment的名词复数 );天然色素
参考例句:
  • The Romans used natural pigments on their fabrics and walls. 古罗马人在织物和墙壁上使用天然颜料。 来自辞典例句
  • The original white lead pigments have oxidized and turned black. 最初的白色铅质颜料氧化后变成了黑色。 来自辞典例句
11 previously bkzzzC     
adv.以前,先前(地)
参考例句:
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
12 robust FXvx7     
adj.强壮的,强健的,粗野的,需要体力的,浓的
参考例句:
  • She is too tall and robust.她个子太高,身体太壮。
  • China wants to keep growth robust to reduce poverty and avoid job losses,AP commented.美联社评论道,中国希望保持经济强势增长,以减少贫困和失业状况。
13 lighter 5pPzPR     
n.打火机,点火器;驳船;v.用驳船运送;light的比较级
参考例句:
  • The portrait was touched up so as to make it lighter.这张画经过润色,色调明朗了一些。
  • The lighter works off the car battery.引燃器利用汽车蓄电池打火。
14 antelope fwKzN     
n.羚羊;羚羊皮
参考例句:
  • Choosing the antelope shows that China wants a Green Olympics.选择藏羚羊表示中国需要绿色奥运。
  • The tiger was dragging the antelope across the field.老虎拖着羚羊穿过原野。
15 genetic PgIxp     
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。
16 mechanisms d0db71d70348ef1c49f05f59097917b8     
n.机械( mechanism的名词复数 );机械装置;[生物学] 机制;机械作用
参考例句:
  • The research will provide direct insight into molecular mechanisms. 这项研究将使人能够直接地了解分子的机理。 来自《简明英汉词典》
  • He explained how the two mechanisms worked. 他解释这两台机械装置是如何工作的。 来自《简明英汉词典》
17 underlying 5fyz8c     
adj.在下面的,含蓄的,潜在的
参考例句:
  • The underlying theme of the novel is very serious.小说隐含的主题是十分严肃的。
  • This word has its underlying meaning.这个单词有它潜在的含义。
18 camouflage NsnzR     
n./v.掩饰,伪装
参考例句:
  • The white fur of the polar bear is a natural camouflage.北极熊身上的白色的浓密软毛是一种天然的伪装。
  • The animal's markings provide effective camouflage.这种动物身上的斑纹是很有效的伪装。
19 predators 48b965855934a5395e409c1112d94f63     
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面)
参考例句:
  • birds and their earthbound predators 鸟和地面上捕食它们的动物
  • The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
20 chipmunks 489f8c4fac3b4e144efa2b0a3fb81d6a     
n.金花鼠( chipmunk的名词复数 )
参考例句:
21 leopards 5b82300b95cf3e47ad28dae49f1824d1     
n.豹( leopard的名词复数 );本性难移
参考例句:
  • Lions, tigers and leopards are all cats. 狮、虎和豹都是猫科动物。 来自《简明英汉词典》
  • For example, airlines never ship leopards and canaries on the same flight. 例如,飞机上从来不会同时运送豹和金丝雀。 来自英语晨读30分(初三)
22 racing 1ksz3w     
n.竞赛,赛马;adj.竞赛用的,赛马用的
参考例句:
  • I was watching the racing on television last night.昨晚我在电视上看赛马。
  • The two racing drivers fenced for a chance to gain the lead.两个赛车手伺机竞相领先。
TAG标签: species color gene
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