Human growth is regulated by a complex interaction between genetic and environmental factors. Illness and malnutrition depress growth rates, especially during infancy and early childhood when growth is most sensitive to environmental factors. Later childhood and adolescent growth is thought to be more responsive to genetic (combined with environmental) factors. Although long bone length and stature are often used as indicators of population health, other relevant skeletal variables have the potential to elucidate the ontogenetic impact of environmental versus genetic influences. Endosteal dimensions respond to diet and disease and should reflect environmental factors during early growth; whereas articular growth is thought to be more genetically canalized, thus differences should become more evident during adolescence.
In this study, growth in multiple skeletal features – long bone lengths, epiphyseal dimensions, and cross-sectional geometry – was evaluated in four skeletal samples and examined in two components. Component 1 examines growth between socioeconomic groups from a very large, relatively genetically homogeneous population (Barton-upon-Humber, UK). Component 2 compares growth between genetically (and environmentally) disparate skeletal samples (Barton-upon-Humber; Alaskan Tigara; Arikara from South Dakota; and Neolithic Çatalhöyük, Turkey). Variables were examined using osteometric techniques and reconstructed cross-sectional geometry. Growth analysis was conducted through direct variable comparisons and polynomial regression residuals.
Results indicate that socio-economic status has little effect on body size in Barton-upon-Humber, but cross-sectional dimensions suggest inadequate feeding and more vigorous mechanical loading before mid-adolescence in higher status burials. Settlement history may affect the biological impact of socio-economic status on the ontogenetic process. Component 2 identified potential sample-specific growth rates and similar endosteal dimensions during early growth. Sample-specific differences in body size emerge after 8 years of age. However, sample-relative body proportions and cross-sectional dimensions emerge in the first year of life. This indicates slight environmental disparities and an increasing impact of genetics on body size, while ecogeographic-related body form and diaphyseal robusticity may be more attenuated to genetic variation during ontogeny. Increased understanding of the complex and subtle contributions of genetic and environmental influence on multiple skeletal variables has broad bioarchaeological implications for the assessment of health, growth, and skeletal variation in past populations.
|1996||Carter DR, Van der Meulen MCH, Beaupré GS. Mechanical factors in bone growth and development. Bone. January 1996;18(1)(suppl 1):S5-S10.|
|1983||Ruff CB, Hayes WC. Cross‐sectional geometry of Pecos Pueblo femora and tibiae: a biomechanical investigation, II: sex, age, and side differences. Am J Phys Anthropol. 1983;60(3):383-400.|
|2000||Akhter MP, Iwaniec UT, Covey MA, Cullen DM, Kimmel DB, Recker RR. Genetic variations in bone density, histomorphometry, and strength in mice. Calcif Tiss Int. October 2000;67(4):337-344.|
|1987||Carter DR. Mechanical loading history and skeletal biology. J Biomech. 1987;20(11-12):1095-1109.|
|1983||Ruff CB, Hayes WC. Cross‐sectional geometry of Pecos Pueblo femora and tibiae: a biomechanical investigation, I: method and general patterns of variation. Am J Phys Anthropol. 1983;60(3):359-381.|
|2004||Pearson OM, Lieberman DE. The aging of Wolff's "law": ontogeny and responses to mechanical loading in cortical bone. Yearb Phys Anthropol. 2004;47:63-99.|
|1974||Akaike H. A new look at the statistical model identification. IEEE Trans Automat Contr. December 1974;19(6):716-723.|
|1975||Currey JD, Butler G. The mechanical properties of bone tissue in children. J Bone Joint Surg. September 1975;57A(6):810-814.|
|2002||Robling AG, Turner CH. Mechanotransduction in bone: genetic effects on mechanosensitivity in mice. Bone. November 2002;31(5):562-569.|