Plasticity in the growth of body segments in relation to height‐for‐age and maternal education in Guatemala

Luis Ríos,José Manuel Terán,Barry Bogin,Carlos Varea

doi:10.1002/ajhb.23376

Abstract

ObjectivesPlasticity in the growth of body segments between populations has been researched in relation to migration, temporal change and high‐altitude studies. We study the within population variation in body segments, thus controlling for some of the environmental and genetic differences that could be at play in between populations studies. We test a version of the thrifty phenotype hypothesis, where the growth of head‐trunk and hand are prioritized due to their functional significance over height and leg growth.Materials and methodsA total of 3913 Guatemalan, rural, semi‐urban and urban, Maya and Ladino children 6 to 15 years old were studied. Height, sitting height, leg length, and metacarpal length were studied in relation to three proxies for living conditions: height‐ and leg length‐for‐age, and maternal education. Estimation statistics and null hypothesis significance testing were used to analyze the data.ResultsMetatarsal length and sitting height values were higher than height and leg length respectively. Relative metacarpal length was conserved across height‐for‐age groups. Females were less affected than males for metacarpal length and sitting height, but more affected for leg length.ConclusionOur results agree with the thrifty phenotype hypothesis, where metacarpal and sitting height growth would be prioritized over height and leg length due to greater functional significance.

Highlights

Plasticity refers to the ability of an organism to modify its biology to respond to changes in the environment, when these changes are physiologically stressful (Bogin, 1999)
We study the within population variation in body segments, controlling for some of the environmental and genetic differences that could be at play in between populations studies
Our results agree with the thrifty phenotype hypothesis, where metacarpal and sitting height growth would be prioritized over height and leg length due to greater functional significance

Summary

Introduction

Plasticity refers to the ability of an organism to modify its biology to respond to changes in the environment, when these changes are physiologically stressful (Bogin, 1999). Research on plasticity in growth has analyzed the change in the lengths of body segments in samples living in different environments (Bogin, Smith, Orden, Silva, & Loucky, 2002; Padez, Varela-Silva, & Bogin, 2009; Payne, Kumar, Pomeroy, Macintosh, & Stock, 2018; Pomeroy et al, 2012), or belonging to different generations (Tanner, Hayashi, Preece, & Cameron, 1982) In these studies it has been shown that, in conditions of environmental stress, leg length is often more sensitive than is the head-trunk segment (Bogin et al, 2002; Bogin & Varela-Silva, 2009; Bogin & Varela-Silva, 2010; Leitch, 1951; Tanner et al, 1982), and that tibia and ulna lengths are more sensitive than humerus, hand and foot lengths (Payne, Kumar, et al, 2018; Pomeroy et al, 2012). We do this within the same samples of children and, can exclude any strong influence of possible genetic or environmental differences associated to groups living in different places or periods

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