【Genetic Drift】

基因漂移：原理、实例与影响

最新推荐文章于 2025-12-03 22:25:36 发布

原创

最新推荐文章于 2025-12-03 22:25:36 发布 · 882 阅读

5 ·

CC 4.0 BY-SA版权

文章标签：

#经验分享

基因漂移是指由于随机因素导致种群中等位基因频率的变化。它在小规模种群中更为明显，可能导致瓶颈效应或创始人效应。通过实例解释了如何在假设和真实情况下观察到基因漂移，并与自然选择进行区分。

Definition

Genetic drift is a change in allele frequency in a population, due to a random selection of certain genes. Oftentimes, mutations within the DNA can have no effect on the fitness of an organism. These changes in genetics can increase or decrease in a population, simply due to chance.

Genetic Drift Explained

Although variations of genes (also known as alleles) can be selected for because they help or hinder an organism, other mutations can have no effect. When the allele itself is not responsible for the change in its frequency in a population, genetic drift is acting on the allele. The graph below shows different trajectories for the same genes over time. As you can see, the frequency of these genes can change drastically over time, especially with the smallest populations.

In the largest populations, the allele frequency of each gene stays relatively stable. This happens because the genes are not affecting fitness, and thus do not have a natural selection pressure against or for the allele. In the smallest populations, the frequency of these genes can fluctuate greatly. Some become fixed within the population, while others disappear. These chance events which lead to changes in frequency are called genetic drift.