Bergmann's rule and the thrifty genotype

Area of Science:

• Human biological anthropology
• Ecological rules in human populations
• Human genetics and epidemiology

Background:

• Bergmann's rule posits body weight correlates with climate.
• Roberts demonstrated ecological rules apply to humans, including weight-temperature covariation.
• Oceanic populations present an exception to Bergmann's rule, prompting investigation into underlying genetic factors.

Purpose of the Study:

• To investigate deviations from Bergmann's rule in Oceanic populations.
• To test the applicability of Neel's thrifty genotype model to explain weight variations.
• To explore the link between energetic efficiency selection, modernization, and health outcomes like obesity and NIDDM.

Main Methods:

• Analysis of adult male weight data from 19 Oceanic populations.
• Comparison of observed weights against predicted weights based on Roberts' regression.
• Regression analysis of weight deviations against NIDDM prevalence.

Main Results:

• Oceanic populations exhibit extreme deviations from predicted body weight based on mean annual temperature.
• A highly significant regression (R2 = 0.46; P < 0.001) was found between weight deviations and NIDDM prevalence.
• Results support the hypothesis that the thrifty genotype contributes to high body weight in these populations.

Conclusions:

• The thrifty genotype model provides a plausible explanation for weight variations in Oceanic populations.
• Selection for energetic efficiency during migration may have predisposed these populations to obesity and NIDDM under modernization.
• Further research is warranted to understand the genetic and environmental interplay in human adaptation and health.