神奇鱼类7万年从未交媾
据英国《每日邮报》报道，一项新研究表明一种神奇鱼类全是女儿身，７万年来从未交媾，但一直繁衍至今，在公然挑战达尔文的进化论。这种鱼就是亚马逊帆鳍鲈（Molly）。 英国科学家表示，一般来说，有性物种若以无性繁殖，过不了几代就会出现基因残障，最后绝种。按理说亚马逊帆鳍鲈应该绝种，但它们巧妙地利用遗传基因来得以幸存。众所周知，有雄鱼精子才能形成胚胎，但亚马逊帆鳍鲈的所有后代似乎没有爸爸的一点DNA，而是全部继承了妈妈的基因物质。
但亚马逊帆鳍鲈仍旧繁衍在美国德州东南部和墨西哥西北部的河流中，这令科学家大为意外。
为解开这一谜团，英国爱丁堡大学的科学家通过高性能的计算机系统来研究复杂的数学模型，以分析亚马逊帆鳍鲈的这一特别案例。根据模型计算亚马逊帆鳍鲈数千代鱼的基因变化情况，科学家得出它们应该在7万年前就灭绝了。
为此，科学家理论分析了它们依旧存活了数万年的原因，提出了亚马逊帆鳍鲈的一种“自救”理论――认为它们偶尔会从其它品种的雄鱼中获取一些DNA，以此来触发繁殖，以更新它们的基因库。爱丁堡大学生物科学学院的劳伦斯·洛伊博士说：“我们的研究表明这些鱼真有其特别之处，还有特别的生存诀窍来帮助这种鱼幸存下来。也许是偶然与陌生客交配一下，以保持此物种的繁衍。未来的进一步研究将给我们更多的答案。”
洛伊博士补充说，他们的发现还能帮助他们更多地了解其它物种是如何运作的。“我想一件有趣的事情是我们更多地知道了其它物种也会使用同样的诀窍来生存下来。这可能有更普遍的重大意义。”
此研究成果发表在最新一期的《BMC进化生物学》杂志上。洛伊博士计划采取更进一步的数学检测来继续分析亚马逊帆鳍鲈的自然习性。 怀疑文章的可信度:sad2: :sad2: 同意楼上的，不同鱼种能互相交配？还能保证后代绝大多数基因都和母亲相同？有点科幻了:zzz: 除非这鱼聪明得能知道哪些基因有用，但是，怎么分离出来呢？ 文章有点矛盾吧
既然不交媾，有说和其他物种交配？什么意思？ 人类最好不要这样,不然就太不爽了 这好象是物种进化的一个分支罢了，在底端的一些生物进用其他物种生物进行繁殖，但是却不遗传其他生物的特征。这是很正常的生物繁衍现象啊。 真是有趣的發現...... 这个世界太奇妙了:cry2: 消息可靠程度不知道有多少，说不定是假的！ 自然界是否存在“自我克隆”呢？ :q: 人类会不会是这样变种出现的？？ 克隆鱼啊～～～～～～～～～～～～ 世界真奇妙。。。。:QQ 孤雌生殖的生物其实很多 这个新闻够乱的，即说不交媾，又说偶尔从雄鱼那获得dna，到底有普没有铺 现在这类报道特别多，不知道是真是假` 好在人类不是这样的，要不咱爷们们都靠边儿站了。 可怜的鱼，基本快乐都没有享受过…… 世界真奇妙，什么事都可能发生 说的 挺假得。。。。 以前见过银环海蛇，很长寿。 :loveliness: :loveliness: 奇妙啊 事情离奇，可有链接？
这也算是一种独特的繁殖方式吧 真的假的阿。。。:LL :LL 楼上的各位怎么都不大信啊，自然界就是这样无奇不有 估计人类跟猴类也可以生一个出来了到时候~~~~~~~~~~~ no it's not fake. pls. refer to the following link: [url]http://www.dailymail.co.uk/sciencetech/article-561479/All-girl-fish-species-sex-70-000-years-defying-evolution.html[/url]
the original article is also attached below fyi.
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All-girl fish species that hasn't had sex for 70,000 years 'is defying evolution'
Last updated at 16:05 23 ???? 2008
An all-girl species of fish which has survived for 70,000 years without the aid of sexual reproduction is defying the laws of evolution, new research shows.
British scientists say the Amazon Molly fish ought by rights to be extinct but may be employing special genetic survival "tricks".
The all-female fish interact sexually with males of other species to trigger a bizarre reproduction known as gynogenesis.
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Good golly miss Molly! The Amazon Molly fish reproduces by using other species' sperm
The male fishes' sperm sparks the development of an embryo, but none of the male DNA appears to be passed on to the offspring. Only the mother's genes are inherited.
The species is still thriving in rivers in south-east Texas and north-east Mexico, but are named "Amazons" after the all-women warriors of Greek myth.
Typically, when creatures reproduce asexually, harmful changes creep into their genes over many generations.
The species will eventually have problems reproducing and can often fall victim to extinction.
Scientists at the University of Edinburgh have been studying complex mathematical models on a highly powerful computing system to look at the case of the Amazon Molly.
Researchers calculated the time to extinction for the fish based on modelling genetic changes over many thousands of generations.
They are now able to say conclusively, for the first time, that the fish ought to have become extinct within the last 70,000 years, based on the current simple models.
According to the report in the BMC Evolutionary Biology journal, one theory is that the fish may occasionally be taking some of the DNA from the males that trigger reproduction, in order to refresh their gene pool.
Dr Laurence Loewe, of the university's School of Biological Sciences, said: "What we have shown now is that this fish really has something special going on and that some special tricks exist to help this fish survive.
"Maybe there is still occasional sex with strangers that keeps the species alive. Future research may give us some answers."
He added that their findings could also help them understand more about how other creatures operate.
"I think one of the interesting things is that we are learning more about how other species might use these tricks as well," he said. "It might have a more general importance."
Now Dr Loewe plans to look for more answers by carrying out further mathematical tests while an Austrian colleague will continue to analyse the fish in their natural habitat. 呃……
神奇的大自然啊~~:yy9:
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