Beginning in the 1930s, evolution became an experimental subject. New techniques, especially in Drosophila, made possible quantitative analysis of natural populations. In addition to a large number of studies on many species, there were four major controversies that dominated much of the discussion and experimentation. Some of the arguments were quite heated. These controversies were: Wright vs Fisher on Wright's shifting-balance theory; dominance vs overdominance as an explanation of heterosis; the classical vs balance hypothesis for genetic variability; the neutral theory of molecular evolution. Curiously, most of these issues were not really resolved. Rather they were abandoned in favor of more tractable studies made possible by the new molecular methods.

中文翻译：

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本世纪中叶的人口遗传学争议。

从1930年代开始，进化成为实验性课题。新技术，特别是在果蝇中，使得对自然种群进行定量分析成为可能。除了对许多物种的大量研究之外，还有四个主要争议占据了讨论和实验的大部分。一些争论非常激烈。这些争论是：关于赖特的转移平衡理论的赖特与费舍尔；优势vs优势占优势的解释；遗传变异的经典与平衡假设；中性分子进化论。奇怪的是，其中大多数问题并未真正解决。相反，它们被抛弃了，而被新的分子方法所支持的更易于研究的研究所支持。