Wells, Jonathan CK;
(2023)
Natural selection and human adiposity: crafty genotype, thrifty phenotype.
Philosophical Transactions of the Royal Society B: Biological Sciences
, 378
(1885)
, Article 20220224. 10.1098/rstb.2022.0224.
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Abstract
Evolutionary perspectives on obesity have aimed to understand how the genetic constitution of individuals has been shaped by selective pressures such as famine, predation or infectious disease. The dual intervention model assumes strong selection on lower and upper limits of adiposity, but negligible fitness implications for intermediate adiposity. These frameworks are agnostic to age, sex and condition. I argue that selection has favoured a 'crafty genotype'-a genetic basis for accommodating variability in the 'fitness value' of fat through phenotypic plasticity, depending on the endogenous and exogenous characteristics of each individual. Hominin evolution occurred in volatile environments. I argue that the polygenetic basis of adiposity stabilizes phenotype in such environments, while also coordinating phenotypic variance across traits. This stability underpins reaction norms through which adiposity can respond sensitively to ecological factors. I consider how the fitness value of fat changes with age, sex and developmental experience. Fat is also differentially distributed between peripheral and abdominal depots, reflecting variable prioritization of survival versus reproduction. Where longevity has been compromised by undernutrition, abdominal fat may promote immediate survival and fitness, while long-term cardiometabolic risks may never materialize. This approach helps understand the sensitivity of adiposity to diverse environmental factors, and why the health impacts of obesity are variable. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part I)'.
| Type: | Article |
|---|---|
| Title: | Natural selection and human adiposity: crafty genotype, thrifty phenotype |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1098/rstb.2022.0224 |
| Publisher version: | https://doi.org/10.1098/rstb.2022.0224 |
| Language: | English |
| Additional information: | © 2023 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. |
| Keywords: | Adiposity, evolution, fat distribution, infectious disease, phenotypic plasticity, reaction norm, Humans, Adiposity, Obesity, Genotype, Phenotype, Selection, Genetic |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > UCL GOS Institute of Child Health UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > UCL GOS Institute of Child Health > Population, Policy and Practice Dept |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10174214 |
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