內(nèi)共生學(xué)說認(rèn)為線粒體基因序列一定被成功地融合到核基因組中以維持真核細(xì)胞的代謝,。但是插入事件的發(fā)生通常帶來有害的影響，導(dǎo)致一些由于線粒體基因拷貝產(chǎn)生的疾病,。除此之外,，新的遺傳物質(zhì)的融合可能破壞合適的翻譯系統(tǒng)。由此可見,，相對很少的融合事件的發(fā)生才能產(chǎn)生重要的功能性的影響,。線粒體基因的插入對增加基因組的復(fù)雜性是很重要的，有研究報道表明人類基因組中包含1000個編碼線粒體蛋白的基因,，超過90%的線粒體蛋白是核基因所編碼的,。
然而，線粒體基因的空間如何分布,，從線粒體DNA中來的假基因在基因組中又是如何的定位的,，我們都不是很清楚。首爾國立大學(xué)農(nóng)業(yè)生物技術(shù)系的Sunjin Moon等人研究認(rèn)為線粒體假基因的定位表明了進(jìn)化的一個軌跡,，好比一個分子化石。他們利用基于概率的方法和自舉的方法估計參數(shù)閾值,，這個參數(shù)閾值能很好地描述線粒體基因在核基因組中的分布情況,。結(jié)果分析得到幾乎一半的線粒體基因定位在染色體的著絲粒和亞著絲粒區(qū)域。巧合的是這些基因簇的大小從0.085 Mb到3.2Mb,，恰好與進(jìn)化區(qū)域的平均大小相一致,，他們認(rèn)為人類基因組中線粒體基因的定位傾向于獨立的。相關(guān)論文發(fā)表在愛思唯爾期刊《基因組學(xué)》（Genomics）上,。（生物谷Bioon.com）
生物谷推薦原始出處：
Genomics,，Volume 92, Issue 2, August 2008, Pages 85-93，Sunjin Moon,，Heebal Kim
Organization and evolution of mitochondrial gene clusters in human
Sunjin Moona, Seoae Chob and Heebal Kima, b, ,
aLaboratory of Bioinformatics and Population Genetics, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea
bGraduate Program in Bioinformatics, Seoul National University, Seoul 151-742, Korea
Currently, the spatial patterns of mitochondrial genes and how the genomic localization of (pseudo)genes originated from mitochondrial DNA remain largely unexplained. The aim of this study was to elucidate the organization of mitochondrial (pseudo)genes given their evolutionary origin. We used a keyword finding method and a bootstrapping method to estimate parameter values that represent the distribution pattern of mitochondrial genes in the nuclear genome. Almost half of mitochondrial genes showing physical clusters were located in the pericentromeric and subtelomeric regions of the chromosome. Most interestingly, the size of these clusters ranged from 0.085 to 3.2 Mb (average ± SD 1.3 ± 0.73 Mb), which coincides with the size of the evolutionary pocket, or the average size of evolutionary breakpoint regions. Our findings imply that the localization of mitochondrial genes in the human genome is determined independent of adaptation.
