相关实验视频
Updated: Jul 5, 2026

12:00
A Practical Guide to Phylogenetics for Nonexperts
Published on: February 5, 2014
遗传学MCMC算法对树木混合物具有误导性
1Department of Statistics, University of California at Berkeley, Berkeley, CA 94720, USA. mossel@stat.berkeley.edu.
概括
使用马尔科夫链蒙特卡洛 (MCMC) 的贝叶斯系遗传学推断可能是误导性的. 我们的研究表明,MCMC算法可能需要指数级的时间来趋同,特别是在冲突的遗传学信号的情况下.
科学领域:
- 计算生物学 计算生物学
- 进化生物学 进化生物学
- 统计建模 统计建模
背景情况:
- 马尔科夫链蒙特卡洛 (MCMC) 算法是贝叶斯族的基因推理的基础.
- 评估这些算法的融合率对于可靠的遗传学重建至关重要.
研究的目的:
- 理论上分析常用的马尔科夫链的融合速率.
- 为了调查MCMC的遗传学分析中迅速趋同的欺骗性外观.
主要方法:
- 在族系树的空间上对日志概率函数进行数学分析.
- 从两个树的混合生成的N个字符的收率的理论证明.
主要成果:
- 当数据来自两个树的混合时,马尔科夫链表现出指数长的收时间 (以N).
- 概率图可以欺骗性地暗示到一个单一树的快速收,掩盖缓慢的实际收.
结论:
- 贝叶斯的MCMC方法可能会产生误导性的遗传学结果,当面对数据包含相互矛盾的信号.
- 对数据中的每一个独特的遗传信号,应单独进行遗传学重建.
相关概念视频
Mismatch Repair
Overview
Mutation, Gene Flow, and Genetic Drift
In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).Mechanisms of Genetic VariationThe original sources of genetic variation are mutations,...
Genetic Drift
Natural selection—probably the most well-known evolutionary mechanism—increases the prevalence of traits that enhance survival and reproduction. However, evolution does not merely propagate favorable traits, nor does it always benefit populations.Life is not fair. A deer grazing contentedly in a field can have her meal cut tragically short by a bolt of lightning. If the doomed doe is one of only three in the population, 1/3 of the population’s gene pool is lost. Random events like this can...
Chi-square Analysis
The chi-square test is a statistical hypothesis test. It is used to check whether there is a significant difference between an expected value and an observed value. In the context of genetics, it enables us to either accept or reject a hypothesis, based on how much the observed values deviate from the expected values.
The chi-square test was developed by Pearson in 1990.
The first step of performing a Chi-square analysis is to establish a null hypothesis, which assumes that there is no real...
The chi-square test was developed by Pearson in 1990.
The first step of performing a Chi-square analysis is to establish a null hypothesis, which assumes that there is no real...
Mismatch Repair
Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
Survival Tree
Survival trees are a non-parametric method used in survival analysis to model the relationship between a set of covariates and the time until an event of interest occurs, often referred to as the "time-to-event" or "survival time." This method is particularly useful when dealing with censored data, where the event has not occurred for some individuals by the end of the study period, or when the exact time of the event is unknown.
Building a Survival Tree
Constructing a survival tree begins...
Building a Survival Tree
Constructing a survival tree begins...

