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Who Passed on the Genes?
Key DNA May Be From Dad After All

A type of DNA[1] long thought to be inherited only from mothers may be influenced by dad after all, a new analysis indicates. If proven true, scientists may have to rethink some basic beliefs about the timing of human evolution.

Estimates of when humans migrated into Asia and Europe and even the age of "Eve", the earliest common female ancestor, are based on the changes in mitochondrial DNA[2], which was assumed to come only from mothers.

"Many inferences about the pattern and tempo of human evolution and mitochondrial DNA evolution have been based on the assumption of clonal inheritance[3]. These inferences will now have to be reconsidered," conclude the researchers led by Philip Awadalla of the University of Edinburgh, Scotland.

However, there is also DNA in the mitochondria, the energy-producing portions of the cell, and that had been thought to come from the mother alone.

注释：

[1]DNA:
DNA是deoxyribonucleic acid（脱氧核糖核酸）的简称。DNA是人的遗传物质，其多态性有200多种，且终身不变。可以说，除了同卵孪生外，实际上没有两个人的DNA指纹图案是完全相同的。由于DNA技术科学、公正、准确，在法医认证、计划生育、移民公证等方面往往起到一锤定音的作用，因此人们把它称为"DNA判官"。

[2]mitochondrial DNA:
线粒体DNA，就是存在于线粒体中的DNA，线粒体是细胞的一部分，能够制造能量。

[3]clonal inheritance:
无性遗传。我们知道，无性生殖一般也称为"克隆"。众所周知的绵羊"多莉"就是第一只用克隆技术培育出来的羊。

一项新的分析指出，一种长期以来一直被认为来源于母亲的脱氧核糖核酸（DNA）很可能受到父亲方面的影响。如果一经证实，科学家们将不得不对一些有关人类进化时间方面的奠基理论进行重新考虑了。

对人类何时迁徙到亚洲和欧洲，甚至对"夏娃"这位全人类最早的女性祖先年龄的估计都是建立在线粒体DNA变化的基础之上的，而这种线粒体DNA是被假设来源于母体的。

苏格兰爱丁堡大学Philip Awadalla 手下的研究人员总结道："许多对于人类和线粒体DNA进化的模式和速度的推论都是以无性遗传为基础的，而这些推论现在将不得不重新考虑了。"

然而，在细胞中产生能量的部分---线粒体中的确存在着DNA，通常人们认为它们仅仅是来源于母体的。