Selection on maternal and neonate size at birth.
Neonatal size is an important factor in determining the survivorship of infants within the first month of life. Because maternal size has an influence on neonatal size, selection should operate on those characters correlated with birth weight and gestational age, including maternal prepregnancy weight, height, and age. In the present study we use a path-analysis approach to examine the operation of selection on both neonatal and maternal size. We found that neonatal survivorship depends not only on the size of the infant at birth but also on a negative allometric relationship between the size of the neonate and the size of the mother. Thus, although the size of the mother has no direct effect on neonatal mortality, the mothers of surviving infants tend to be smaller relative to the size of their neonate. This may provide a mechanism whereby selection maintains a balance between maternal size and neonate size.
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SJ
Department of Anthropology, University of Michigan, Ann Arbor 48109.
Frisancho
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D000328:Adult; D000367:Age Factors; D000886:Anthropometry; D001724:Birth Weight; D044383:Black People / Q000235:genetics*; D001824:Body Constitution; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008954:Models, Biological; D009035:Mothers; D011247:Pregnancy; D012044:Regression Analysis; D014481:United States; D044465:White People / Q000235:genetics*; D001741:Black or African American