來自加拿大多倫多大學,，多倫多成癮與心理衛(wèi)生研究中心,，以及瑞士,，澳大利亞的研究者在最新一期的Nature Genetics發(fā)表研究成果,，該研究文章在遺傳學方面提出了新的問題,，質疑DNA作為唯一遺傳物質的學說,。
一直以來，經典的遺傳學說認為DNA是遺傳信息的載體,，人類所有的信息都存在于這個小小的染色體上,。從父母親那遺傳來的形狀取決于DNA序列,。文章作者Art Petronis教授否定了這一論斷，他認為DNA不是唯一的遺傳信息載體,，還有其他的表觀遺傳調控因子在遺傳過程中起關鍵的作用,，比如說，甲基化（可能導致基因沉默）,。
經典的遺傳學研究方法是比較同卵雙胞胎和異卵雙胞胎的遺傳情況,。文章通訊作者，成癮與心理衛(wèi)生研究中心表觀遺傳學實驗室主任Art Petronis教授綜合分析了114對同卵雙胞胎和80對異卵雙胞胎的遺傳情況,。
研究小組用一種芯片（12K CpG island microarrays）對雙胞胎的白細胞（WBC）和面部上皮細胞進行甲基化分析,。對同卵雙胞胎的基因組上約6000個獨立區(qū)域的亞穩(wěn)定性進行了分析。將同卵及異卵雙胞胎進行組內相關性對比,，發(fā)現異卵雙胞胎的面部上皮細胞的表觀遺傳學差異十分大,。盡管，異卵雙胞胎的差異性可以用DNA序列不同來解釋,，但是,，用silico SNP分析法進行深入研究發(fā)現，這些差異其實與表觀遺傳調節(jié)因子的差異有很大關聯,。
這些研究結果顯示,，表觀遺傳學調節(jié)因子在遺傳上起重要的作用，因此說DNA序列不是唯一的遺傳基礎,。這種表觀遺傳學說有助于解釋目前人類疾病中的謎團,，比如說，某種疾病只發(fā)生在同卵雙胞胎中的一位,；有些遺傳疾病的易感性男女有差異（比如男性更易發(fā)孤獨癥,，而女性更易發(fā)狼瘡）；有些疾病甚至在發(fā)病過程中也存在差異,。
表觀遺傳學疾病學說更有利于科學家研究各類遺傳疾病,，最終這一學說可能提高人類對疾病的診斷和治療水平。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature Genetics 41, 240 - 245 (2009) Published online: 18 January 2009 | doi:10.1038/ng.286
DNA methylation profiles in monozygotic and dizygotic twins
Zachary A Kaminsky1,2, Thomas Tang1, Sun-Chong Wang1,3, Carolyn Ptak1,2, Gabriel H T Oh1,2, Albert H C Wong1,2, Laura A Feldcamp1,2, Carl Virtanen4, Jonas Halfvarson5,6, Curt Tysk5,6, Allan F McRae7, Peter M Visscher7, Grant W Montgomery7, Irving I Gottesman8, Nicholas G Martin7 & Art Petronis1,2
Twin studies have provided the basis for genetic and epidemiological studies in human complex traits1, 2. As epigenetic factors can contribute to phenotypic outcomes, we conducted a DNA methylation analysis in white blood cells (WBC), buccal epithelial cells and gut biopsies of 114 monozygotic (MZ) twins as well as WBC and buccal epithelial cells of 80 dizygotic (DZ) twins using 12K CpG island microarrays3, 4. Here we provide the first annotation of epigenetic metastability of 6,000 unique genomic regions in MZ twins. An intraclass correlation (ICC)-based comparison of matched MZ and DZ twins showed significantly higher epigenetic difference in buccal cells of DZ co-twins (P = 1.2 10-294). Although such higher epigenetic discordance in DZ twins can result from DNA sequence differences, our in silico SNP analyses and animal studies favor the hypothesis that it is due to epigenomic differences in the zygotes, suggesting that molecular mechanisms of heritability may not be limited to DNA sequence differences.
1 Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada.
2 University of Toronto, Toronto, Ontario M5S 1A1, Canada.
3 Institute of Systems Biology and Bioinformatics, National Central University, Chungli 320, Taiwan.
4 University Health Network Microarray Centre, Toronto, Ontario M5G 1L7, Canada.
5 Division of Gastroenterology, Department of Medicine, 701 85 ?rebro University Hospital, ?rebro, Sweden.
6 School of Health and Medical Sciences, ?rebro University, 701 85 ?rebro, Sweden.
7 Queensland Institute of Medical Research, Brisbane 4029, Queensland, Australia.
8 University of Minnesota, Minneapolis, Minnesota 55454, USA.
