Mendel proposed that the heritable material is particulate and that transmission of alleles is unbiased. An assumption of unbiased transmission was necessary to show how variation can be preserved in the absence of selection, so overturning an early objection to Darwinism. In the second half of the twentieth century, it was widely recognised that even strongly deleterious alleles can invade if they have strongly biased transmission (i.e. strong segregation distortion). The spread of alleles with distorted segregation can explain many curiosities. More recently, the selectionist–neutralist duopoly was broken by the realisation that biased gene conversion can explain phenomena such as mammalian isochore structures. An initial focus on unbiased transmission in 1919, has thus given way to an interest in biased transmission in 2019. A focus on very weak bias is now possible owing to technological advances, although technical biases may put a limit on resolving power. To understand the relevance of weak bias we could profit from having the concept of the effectively Mendelian allele, a companion to the effectively neutral allele. Understanding the implications of unbiased and biased transmission may, I suggest, be a good way to teach evolution so as to avoid psychological biases.

中文翻译：

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一个世纪的遗传和进化偏见

孟德尔提出可遗传物质是颗粒状的，等位基因的传播是无偏的。无偏传播的假设是必要的，以表明如何在没有选择的情况下保持变异，从而推翻早期对达尔文主义的反对。在 20 世纪下半叶，人们普遍认识到，即使是强有害等位基因，如果它们具有强烈的偏向性传播（即强烈的分离扭曲），也可以入侵。具有扭曲分离的等位基因的传播可以解释许多好奇心。最近，由于意识到有偏见的基因转换可以解释哺乳动物等粒结构等现象，选择主义者-中立主义者的双头垄断被打破。1919 年最初关注无偏传输，因此在 2019 年让位于对有偏传输的兴趣。由于技术进步，现在可以关注非常弱的偏差，尽管技术偏差可能会限制分辨率。为了理解弱偏差的相关性，我们可以从有效孟德尔等位基因的概念中获益，有效孟德尔等位基因是有效中性等位基因的伴侣。我认为，了解无偏见和有偏见传播的含义可能是教授进化以避免心理偏见的好方法。