一直以來，科學(xué)家們都確信每個(gè)細(xì)胞內(nèi)的DNA都是相同的,。而一項(xiàng)最近的研究成果卻對(duì)此提出了質(zhì)疑,，蒙特利爾大學(xué)的研究人員最近發(fā)現(xiàn)，并不是所有的細(xì)胞中的DNA都是相同的,。這一發(fā)現(xiàn)對(duì)過去15年對(duì)人類疾病的研究有重大意義,。由于對(duì)于癌癥以外的其他疾病，研究人員很難從患者身上采集病變標(biāo)本,，因此,，研究人員一直都致力于研究血液。然而,，如果事實(shí)證明,，血液和組織細(xì)胞的基因不匹配，那么這些研究或許從一開始就是有缺陷的,。這一發(fā)現(xiàn)將發(fā)表在7月的《人類突變》雜質(zhì)上,。
本次發(fā)現(xiàn)源于施韋策博士，布魯斯博士和洛林博士及其同事對(duì)主動(dòng)脈瘤遺傳原因的研究,。當(dāng)他們重點(diǎn)研究控制細(xì)胞死忙的BAK基因時(shí),，他們有了驚人的發(fā)現(xiàn)。主動(dòng)脈瘤是一種非常罕見的腦血管疾病,，當(dāng)他們對(duì)同一個(gè)患者的血細(xì)胞和組織細(xì)胞的BAK基因進(jìn)行比較發(fā)現(xiàn),，這兩種細(xì)胞內(nèi)的BAK基因有著明顯區(qū)別。隨后,，他們又對(duì)健康人兩種細(xì)胞內(nèi)的進(jìn)行了比較,，同樣發(fā)現(xiàn)了這種差異。
研究人員解釋道：“對(duì)于癌癥以外的其他疾病,，通常我們只能對(duì)血液進(jìn)行研究,，傳統(tǒng)上，當(dāng)我們?cè)噲D尋找一些疾病的遺傳因素時(shí),，血液將告訴我們組織的變化,，而現(xiàn)在看來，卻好像不是這樣的,。除去治療的影響不計(jì),，單純從遺傳學(xué)角度看，不是每個(gè)細(xì)胞都相同這是非常重要的,。早些年,，人們就對(duì)基因組關(guān)聯(lián)大肆宣傳，研究人員從成千上萬的人中提取血液樣本進(jìn)行研究,，然而,，他們期盼的巨大突破卻一直沒有，或許,，我們的發(fā)現(xiàn)可以解釋其失敗的某些原因,。”
主動(dòng)脈瘤主要影響一些吸煙，有高血壓和高膽固醇的老年人,，它往往沒有癥狀,，但在99%的情況下。其可導(dǎo)致主動(dòng)脈破裂而死亡,。研究人員認(rèn)為,，這一發(fā)現(xiàn)或許將為我們治療主動(dòng)脈瘤帶來新的方法，并縮短其治療周期,，如果真的實(shí)現(xiàn)的話,，這將是個(gè)十分重大的突破。（生物谷Bioon.com）
生物谷推薦原始出處：
Human Mutation Volume 30 Issue 7, Pages 1043 - 1047
BAK1 gene variation and abdominal aortic aneurysms
Bruce Gottlieb 1 2 *, Lorraine E. Chalifour 1 3 4 5, Benjamin Mitmaker 6, Nathan Sheiner 6, Daniel Obrand 6, Cherrie Abraham 6, Melissa Meilleur 1, Tomoko Sugahara 1, Ghassan Bkaily 7, Morris Schweitzer 1 4
1Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, Montréal, Québec, Canada
2Department of Human Genetics, Department of Medicine, McGill University, Montréal, Canada
3Division of Experimental Medicine, McGill University, Montréal, Canada
4Departments of Endocrinology, McGill University, Montréal, Canada
5Bank of Montreal Research Center for the Study of Heart Disease in Woman, McGill University, Montréal, Canada
6Department of Surgery, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montréal, Canada
7Department of Anatomy and Cell Biology, University of Sherbrooke, Quebec, Canada
We sought to examine the role of genetics in the multifactorial disease, abdominal aortic aneurysm (AAA), by studying sequence variation in the BAK1 gene (BAK1) that codes for an apoptotic-promoting protein, as chronic apoptosis activation has been linked to AAA development and progression. BAK1 abdominal aorta cDNA from AAA patients and nondiseased individuals were compared with each other, as well as to the BAK1 genomic sequence obtained from matching blood samples. We found specific BAK1 single nucleotide polymorphism (SNP) containing alleles in both aneurysmic (31 cases) and healthy aortic tissue (5 cases) without seeing them in the matching blood samples. These same BAK1 SNPs have been reported, although rarely (average frequency <0.06%), in reference BAK1 DNA sequences. Based on this and other similar observations, we propose a novel hypothesis postulating that multiple variants of genes may preexist in minority forms within specific nondiseased tissues and be selected for, when intra- and/or extracellular conditions change. Therefore, the fact that different BAK1 variants can exist in both diseased and nondiseased AA tissues compared to matching blood samples, together with the rare occurrence of these same SNPs in reference sequences, suggests that selection may be a significant factor in AAA ontogeny. Hum Mutat 30:1-5, 2009. ? 2009 Wiley-Liss, Inc.
