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  • General

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  • 哈迪温贝格

    Stones balanced on a wooden stick, representing the concept of equilibrium in genetics.

    Can these stones keep balance indefinitely?
    ::这些石头能永远保持平衡吗?

    If balance, or equilibrium, is to be maintained, there must be no outside influences on the stones. Equilibrium can also be maintained within a population's genes ; that means, no evolution can occur. But outside influences usually prevent equilibrium from staying established.
    ::如果要保持平衡或平衡,就不能对宝石产生外部影响。 平衡也可以在人口基因中维持;这意味着不可能发生进化。 但外部影响通常会阻碍平衡的建立。

    Hardy-Weinberg Equilibrium
    ::哈迪温伯格平衡

    Sometimes understanding how common a gene is within a is necessary. Or, more specifically, you may want to know how common a certain form of that gene is within the population, such as a recessive form. This can be done using the Hardy-Weinberg model, but it can only be done if the frequencies of the genes are not changing.
    ::有时候,理解基因在某种基因中的共同程度是必要的。 或者,更具体地说,你可能想知道该基因的某种形式在人群中有多常见,比如休眠形式。 这可以通过哈代-温伯格模型来实现,但只有在基因频率没有变化的情况下才能做到。

    The Hardy-Weinberg model describes how a population can remain at genetic equilibrium , referred to as the Hardy-Weinberg equilibrium . Genetic equilibrium occurs when there is no evolution within the population. In other words, the frequency of alleles (variants of a gene) will be the same from one generation to another. At genetic equilibrium, the gene or allele frequencies are stable — they do not change. For example, let's assume that red hair is determined by the inheritance of a gene with two alleles— R and r . The dominant allele , R , encodes for non-red hair, while the recessive allele , r , encodes for red hair. If a population's gene pool contains 90% R and 10% r alleles, then the next generation would also have 90% R and 10% r alleles. However, this only works under a strict set of conditions.
    ::Hardy-Weinberg模型描述人口如何保持基因平衡,称为Hardy-Weinberg平衡。遗传平衡发生时人口内部没有进化。换句话说,异基因(基因的变异性)的频率在一代人之间是相同的。在基因平衡方面,基因或异基因频率是稳定的 — — 它们不会改变。例如,让我们假设红色头发是由具有两种异性基因的遗传遗传所决定的——R和r。主要异性、R、非红发编码,而隐性异性、r、红发编码。如果人口的基因库含有90%R和10%的异性,那么下一代也将拥有90%R和10%的异性。然而,这只有在一套严格的条件下才能起作用。

    The five conditions that must be met for genetic equilibrium to occur include:
    ::实现遗传平衡必须满足的五个条件包括:

    1. No (change) in the sequence.
      ::顺序没有变化。
    2. No migration (moving into or out of a population).
      ::不移徙(迁入或迁出人口)。
    3. A very large population size .
      ::人口规模非常庞大。
    4. Random mating .
      ::随机交配
    5. No .
      ::没有。

    These five conditions rarely occur in nature. When one or more of the conditions does not exist, then evolution can occur. As a result, allele frequencies are constantly changing, and populations are constantly evolving. As mutations and natural selection occur frequently in nature, it is difficult for a population to be at genetic equilibrium.
    ::这五个条件在性质上很少发生。当一种或多种条件不存在时,就会发生演变。因此,所有频率都在不断变化,人口也在不断变化。随着突变和自然选择在自然界中频繁发生,人口难以达到遗传平衡。

    The Hardy-Weinberg model also serves a mathematical formula used to predict allele frequencies in a population at genetic equilibrium. If you know the allele frequencies of one generation, you can use this formula to predict the next generation. Again, this only works if all five conditions are being met in a population.
    ::Hardy- Weinberg 模型还提供一种数学公式,用于在基因平衡时预测人群中的Alele频率。如果您知道一代人的Alele频率,您可以使用这个公式来预测下一代人。再说一次,只有满足了全部五个条件,这才有效。

    Summary
    ::摘要

    • If a population stays at genetic equilibrium, then no evolution takes place.
      ::如果人口处于遗传平衡状态,则不会发生进化。
    • The Hardy-Weinberg model states that a population will remain at genetic equilibrium as long as five conditions are met: (1) No change in the DNA sequence, (2) No migration, (3) A very large population size, (4) Random mating, and (5) No natural selection.
      ::Hardy-Weinberg模型指出,只要满足以下五个条件,人口将保持遗传平衡sad1) DNA序列不变,(2) 不迁移,(3) 人口规模很大,(4) 随机交配,(5) 自然选择。

    Review
    ::回顾

    1. What is an allele?
      ::什么是埃莱尔?
    2. What is meant by genetic equilibrium?
      ::基因平衡意味着什么?
    3. What conditions are required for the Hardy-Weinberg model to apply?
      ::适用Hardy-Weinberg模式需要哪些条件?
    4. Why is Hardy-Weinberg equlilibrium unlikely?
      ::为什么哈迪 -温伯格 equlilibrium不可能?