稳定和平衡选择之间的区别

Thekey differencebetween stabilizing and balancing selection is thatstabilizing selection is a type ofnatural selectionwhich favours average表型in a population while balancing selection is the maintenance of多个等位基因人群中的基因以增强遗传多样性。

Stabilizing selection is a type of natural selection that applies to a phenotypic trait. It favours average phenotypes in a population. Therefore, it eliminates both types of extreme phenotypes. Ultimately it makes a uniform population. Balancing selection is several selective processes that maintain advantageous genetic diversity within a population by maintaining multiple alleles of a gene. Therefore, it applies to a gene locus.

内容

1.Overview and Key Difference
2.What is Stabilizing Selection
3.What is Balancing Selection
4.Similarities Between Stabilizing and Balancing Selection
5.并排比较 - 以表格形式稳定与平衡选择
6。概括

什么是稳定选择？

Stabilizing selection is a type of natural selection that favours the average individuals in a population. In other words, stabilizing selection pushes a population towards the average or median while eliminating the two extreme phenotypes. The environment normally favours the average phenotype within the population. Stabilizing selection is the quantitative equivalent of balancing selection for a single gene trait.

For example, birth weight in human shows stabilizing selection against very small and very large birth weights. Another example is the body size of a species of lizard belonging to the genusAristelliger. Small lizards and large lizards are eliminated, and the average size lizards are favoured by the natural selection. Stabilizing selection makes the population more uniform since natural selection works against the two extremes.

What is Balancing Selection?

Balancing selection is the maintenance of two or more alleles in a population. It maintains advantageous genetic diversity within populations. There are two key mechanisms for balancing selection. They are heterozygote advantage and frequency-dependent selection. Both of them lead to a stable polymorphic equilibrium state. Heterozygotes show higher relative fitness than both homozygotes, leading to balanced polymorphism. Therefore, the organism will have both alleles of the gene rather than having two copies of either version alone. This brings about a heterozygote advantage.

In frequency-dependent selection, the reproductive success of a phenotype depends on the frequency, especially when it has a lower frequency. Lower the frequency, higher the fitness, leading to a balanced polymorphism. Fitness of a phenotype decreases as it becomes more common. Therefore rare phenotypes show higher fitness and are favoured by the selection. This negative frequency-dependent selection leads to a balanced polymorphism.

What are the Similarities Between Stabilizing and Balancing Selection?

• Stabilizing selection is the quantitative equivalent of balancing selection.
• 两者对于人口平衡都是有利的。

稳定和平衡选择有什么区别？

Stabilizing selection is a type of selection which eliminates both extremes from an array of phenotypes while balancing selection is a number of selective processes that actively maintain multiple alleles of a gene in the gene pool of a population. So, this is the key difference between stabilizing and balancing selection. In stabilizing selection, the mean value of a phenotype is selected on a phenotypic trait while in balancing selection, multiple alleles of a gene are selected.

Moreover, stabilizing selection makes a uniform population while balancing selection concerns the genetic polymorphism.

下面的信息图总结了表格形式的稳定和平衡选择之间的差异。

概括– Stabilizing vs Balancing Selection

稳定和平衡选择是种群中发生的两种选择机制。稳定选择应用于表型性状，同时将平衡选择应用于给定的基因座。稳定选择是一种自然选择，有利于人群中的平均表型，同时消除了两种极端表型。平衡选择是指几种在人群中维持多个基因等位基因的机制。平衡选择通过两种关键机制有助于增加遗传多样性：杂合优势和频率依赖性选择。因此，这是稳定和平衡选择之间差异的摘要。

Reference:

1. “Balancing Selection”. En.Wikipedia.Org, 2020,Available here.

Image Courtesy:

1. “Directional, Disruptive and Stabilizing Selections” By Ibbiologystudentone – Own work(CC BY-SA 4.0)viaCommons Wikimedia