Department of Philosophy, The University of Sydney, Sydney, New South Wales 2006, Australia
Cold Spring Harb Perspect Med. 2021 Sep 1;11(9):a040519. doi: 10.1101/cshperspect.a040519.
Causation has multiple distinct meanings in genetics. One reason for this is meaning slippage between two concepts of the gene: Mendelian and molecular. Another reason is that a variety of genetic methods address different kinds of causal relationships. Some genetic studies address causes of traits in individuals, which can only be assessed when single genes follow predictable inheritance patterns that reliably cause a trait. A second sense concerns the causes of trait differences within a population. Whereas some single genes can be said to cause population-level differences, most often these claims concern the effects of many genes. Polygenic traits can be understood using heritability estimates, which estimate the relative influences of genetic and environmental differences to trait differences within a population. Attempts to understand the molecular mechanisms underlying polygenic traits have been developed, although causal inference based on these results remains controversial. Genetic variation has also recently been leveraged as a randomizing factor to identify environmental causes of trait differences. This technique-Mendelian randomization-offers some solutions to traditional epidemiological challenges, although it is limited to the study of environments with known genetic influences.
因果关系在遗传学中有多个不同的含义。造成这种情况的一个原因是基因的两个概念——孟德尔和分子——之间存在意义上的滑动。另一个原因是，各种遗传方法解决了不同类型的因果关系。一些遗传研究解决了个体特征的原因，只有当单个基因遵循可预测的遗传模式，可靠地导致一个特征时，才能对其进行评估。第二种意义涉及群体内特征差异的原因。虽然可以说某些单基因导致了群体水平的差异，但通常这些说法涉及许多基因的影响。多基因特征可以通过遗传力估计来理解，遗传力估计估计了遗传和环境差异对群体内特征差异的相对影响。虽然基于这些结果的因果推理仍然存在争议，但人们已经开发出了理解多基因特征背后的分子机制的方法。最近，遗传变异也被用作随机因素来识别特征差异的环境原因。这种技术——孟德尔随机化——为解决传统的流行病学挑战提供了一些解决方案，尽管它仅限于研究具有已知遗传影响的环境。
