艾滋病毒进化史或比预想的更长
作者: 来源:生物通 发布者: 亦云 类别:新闻扫描 日期: 2010-09-22 今日/总浏览: 19/19 |
美国亚利桑那大学和图兰大学的研究人员发现艾滋病的远古祖先开始感染猿猴的时间比人们以为的还要早好几万年，这意味着人类艾滋病毒不可能很快停止伤害人类。
过去人们认为艾滋病毒仅仅是在一百多年前才出现，9月17日世界知名杂志《科学》上的一篇论文对艾滋病的进化提出了质疑。研究人员根据对比奥科岛猴免疫缺陷病毒（SIV）的遗传分析认为猴免疫缺陷病毒至少存在了32,000到75,000年时间。不同于人类艾滋病毒（HIV），猴免疫缺陷病毒在大多数灵长类动物宿主中并不会引起艾滋病。如果猴免疫缺陷病毒是经过成千数万年的时间进化为原始非致命性病毒，那么人类艾滋病毒有可能也要经历相当长的时间。
“人类艾滋病毒应该个特例，因为任何其他的免疫缺陷病毒对于它们的宿主都没有如此高的致死率，”亚利桑那大学生态和进化生物学系教授Michael Worobey说。
“如果猴免疫缺陷病毒进化的时间比人们以为的短，我们会认为它是在短的时间内获得了较低的致病力，”Worobey说：“但是我们的发现表明一切与之相反。人类艾滋病毒获得致病力不可能是在短时间内发生的事情。”科学家们相信人类艾滋病毒是从猴免疫缺陷病毒进化而来，那么如果数千万年前人类就与SIV感染的猿猴生存在一起，为什么艾滋病仅从20世纪才出现？
图兰大学的病毒学家Preston Marx说：“20世纪有可能发生了某些事情改变了猴病毒使其能够更有力的流行。我们不知道爆发点是什么，但它一定是存在的。”
Worobey说“通过对奥科岛病毒的研究我们知道人类与猴免疫病毒接触也许已有成千上万年的时间。通过比较这些病毒基因可以重建进化历史，我们虽然不知道在过去的某个时间点确切的发生了什么，但是我们可以尽量找到这些病原体的关系。”
Worobey认为在10,000年前奥比岛与非洲大陆分离前猴缺陷病毒已经存在于整个非洲大陆。
Worobey说：“当奥比岛与非洲大陆分离后，任何在那时候流行的病毒就从非洲大陆的病毒群中分离出来。”
图兰国家灵长动物研究中心的病毒学家Marx对数千万年前分离出来的猿猴的DNA样本进行检测验证了猴缺陷病毒的远古起源。
他的研究小组收集了奥比岛丛林中的样本。科学家们发现了四种猴免疫缺陷病毒株与非洲大陆的病毒存在高度的遗传差异。Worobey比对了这些病毒的DNA序列推测这些病毒株从分离开始算起至少进化了10,000多年
计算机模型显示突变的几率比以前认为的要低，同时还显示病毒已经存在了32,000到75,000年。Marx认为这些数据表明猴免疫缺陷病毒存在的时间有可能更长。
Worobey说研究表明存在大量快速进化的病原体。“我们的研究推测了感冒病毒、艾滋病毒的短期改变，但是我们对推论有一些质疑。我们发现病原体的快速进化与它本身的保守程度之间存在着很大的矛盾。”
“以在孤立的环境下研究这些病毒一个非常独特机遇。就我们所知，没有其他的地方能像奥比岛一样可做准确的时间校准。但是比奥科的一些灵长物种仅剩下几百的个体，有可能在不远的将来就会灭绝。我们也许在10年或20年后就不能够进行此类研究了。” （来源：生物通 何嫱）
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Evolutionary history of HIV or longer than expected
Author: From: Bio Link Posted by: Yi Yun Category: News Scan Date: 2010-09-22 Today View / Total View: 19/19
Arizona University and Tulane University researchers found that the ancient ancestors of HIV infection in monkeys start time even earlier than people thought of tens of years, which means HIV can not quickly stop the human against humanity.
The past, people think that HIV is only a hundred years ago it appeared on Sept. 17 world-renowned magazine "Science" paper on the evolution of AIDS questioned. The researchers based on Bioko Island simian immunodeficiency virus (SIV) Genetic analysis of simian immunodeficiency virus that at least 32,000 to 75,000 years. Unlike human immunodeficiency virus (HIV), simian immunodeficiency virus in the majority of primate hosts and does not cause AIDS. If the simian immunodeficiency virus is thousands of tens of thousands of years after the original evolution of non-lethal virus, human immunodeficiency virus may have undergone a long time.
"Human immunodeficiency virus should be a special case, because any other immunodeficiency virus to their host are not such a high mortality rate," University of Arizona professor of ecology and evolutionary biology Michael Worobey said.
"If the simian immunodeficiency virus evolution than people thought a short time, we will consider it within a short time a lower virulence," Worobey said: "But our findings suggest that all the opposite. Human Pathogenicity of HIV can not be happening in a short time. "scientists believe HIV is the Human Immunodeficiency Virus from monkeys evolved, so if tens of millions of years ago, humans and SIV infection of monkeys live together Why HIV only appeared only from the 20th century?
Tulane University virologist Preston Marx said: "The 20th century there was a possible monkey virus, some things have changed to be more effective popular. We do not know what the outbreak is, but it certainly exists."
Worobey said, "By oko Island Virus We know that the human and simian immunodeficiency virus exposure may have been thousands of years. By comparing the evolution of the virus genes can rebuild history, although we do not know a time in the past The exact point of what happened, but we can try to find the relationship between these pathogens. "
Worobey think that 10,000 years ago, Obi Island and separated from the mainland before the African monkey virus that already exists in the entire African continent.
Worobey said: "When Obi Island and the separation of the African continent, any pandemic virus at that time the African continent from separate virus group."
Tulane National Primate Research Center of the virologist Marx on several million years ago separated the monkey's DNA sample for testing verified the ancient origin of the monkey virus.
His research team collected Obi Island jungle samples. Scientists have discovered four strains of simian immunodeficiency virus and the African continent there is a high degree of genetic difference between the virus. Worobey compared DNA sequences of these viruses suggest that these strains begin to run from the separation of at least 10,000 years of evolution
Computer models show that the probability of mutation lower than previously thought, but also show that the virus has existed for 32,000 to 75,000 years. Marx believe that these data show that the existence of Simian Immunodeficiency Virus of time may be longer.
Worobey said that the existence of a large number of rapid evolution of pathogens. "Our study suggested a cold virus, HIV, short-term changes, but we have some doubts on the inference. We find that the rapid evolution of pathogens and the conservative attitude of its own there are significant contradictions between."
"In an isolated environment to study these viruses a very unique opportunity. To our knowledge, there is no other place like Obi Island can do exactly the same as the time calibration. But some of the primate species on Bioko leaving only a few 100 individuals, may become extinct in the near future. We may be in 10 or 20 years will not be able to undertake such studies. "(Source: Bio-Link HE Qiang)
Author:
Source: Biological Link
Posted by: Yi Yun
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