Format

Send to

Choose Destination
Genet Res (Camb). 2013 Jun;95(2-3):89-109. doi: 10.1017/S0016672313000074.

The causal meaning of Fisher's average effect.

Author information

1
Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Bethesda, MD 20892, USA. leejj5@mail.nih.gov

Erratum in

  • Genet Res (Camb). 2013 Oct;95(5):156.

Abstract

In order to formulate the Fundamental Theorem of Natural Selection, Fisher defined the average excess and average effect of a gene substitution. Finding these notions to be somewhat opaque, some authors have recommended reformulating Fisher's ideas in terms of covariance and regression, which are classical concepts of statistics. We argue that Fisher intended his two averages to express a distinction between correlation and causation. On this view, the average effect is a specific weighted average of the actual phenotypic changes that result from physically changing the allelic states of homologous genes. We show that the statistical and causal conceptions of the average effect, perceived as inconsistent by Falconer, can be reconciled if certain relationships between the genotype frequencies and non-additive residuals are conserved. There are certain theory-internal considerations favouring Fisher's original formulation in terms of causality; for example, the frequency-weighted mean of the average effects equaling zero at each locus becomes a derivable consequence rather than an arbitrary constraint. More broadly, Fisher's distinction between correlation and causation is of critical importance to gene-trait mapping studies and the foundations of evolutionary biology.

PMID:
23938113
PMCID:
PMC3779663
DOI:
10.1017/S0016672313000074
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Cambridge University Press Icon for PubMed Central
Loading ...
Support Center