依据以往的认识，不同物种交配即使生产，下一代也没办法继续繁殖。台湾“中研院”吕俊毅博士团队透过观察酵母菌“种化”基因，解开了不同物种之间交配却无法繁殖的进化密码。
“种”是生物分类最基本的单位，早在八十年前，就有进化大师提出假说，可能是特定基因不兼容的关系，造成不同物种之间的个体，即使交配，生出来的下一代，也不具有繁殖能力。
多年来，全球学者都试图找出这个无法演化的基因密码。台湾“中研院”吕俊毅博士团队利用大量、快速繁殖的酵母菌，清楚完整地呈现出“种化”机制，其中关键就是跟细胞内的粒线体功能有关。
台“中研院”分子生物研究所助研究员吕俊毅博士说：“在我们研究中发现类似的现象，就是他们的粒线体之所以不一样，是因为它们使用能源方式不一样，很显然有一个物种像是柴油引擎，另一个像是汽油引擎，所以说把两个引擎互换的时候，当然就会发现两个功率完全变的不一样。”
研究显示，“种化”的问题关键在于细胞内的粒线体与细胞核不兼容，粒线体可能在演化上，为了适应不同营养环境，偏向不同的代谢方式，导致了两个种的分离。
研究成果对于未来进化研究迈进一大步，受到国际高度瞩目，在生物学术界最顶尖期刊《细胞》（Cell）上发表。这项成果对于未来医学应用有也帮助，可以持续观察粒线体扮演的角色，为癌症与老化方面的研究提供参考。（生物谷Bioon.com）
生物谷推荐原始出处：
Cell，Volume 135, Issue 6, 1065-1073，Hsin-Yi Lee，Jun-Yi Leu
Incompatibility of Nuclear and Mitochondrial Genomes Causes Hybrid Sterility between Two Yeast Species
Hsin-Yi Lee1,3,Jui-Yu Chou1,2,3,Liplee Cheong1,Nai-Hsin Chang1,Shi-Yow Yang1andJun-Yi Leu1,,
1 Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
2 Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
3 These authors contributed equally to this work
Hybrids between species are usually unviable or sterile. One possible mechanism causing reproductive isolation is incompatibility between genes from different species. These 'speciation'genes are interacting components that cannot function properly when mixed with alleles from other species. To test whether such genes exist in two closely related yeast species, we constructed hybrid lines in which one or two chromosomes were derived from Saccharomyces bayanus, and the rest were from Saccharomyces cerevisiae. We found that the hybrid line with Chromosome 13 substitution was completely sterile and identified Aep2, a mitochondrial protein encoded on Chromosome 13, to cause the sporulation defect as S. bayanus AEP2 is incompatible with S. cerevisiae mitochondria. This is caused by the inability of S. bayanus Aep2 protein to regulate the translation of the S. cerevisiae OLI1 mRNA. We speculate that AEP2and OLI1 have evolved during the adaptation of S. bayanus to nonfermentable carbon sources, thereby driving speciation.
