title: Correlation of intergenerational family sizes suggests a genetic component of reproductive fitness.
abstract: Reproductive fitness is a complex phenotype that is a direct measure of Darwinian selection. Estimation of the genetic contribution to this phenotype in human populations is confounded by within-family correlations of sociocultural, economic, and other nongenetic factors that influence family sizes. Here, we report an intergenerational correlation in reproductive success in the Hutterites, a human population that is relatively homogeneous with respect to sociocultural factors that influence fertility. We introduce an estimator of this correlation that takes into account the presence of multiple parent-offspring pairs from the same nuclear family. Statistical significance of the estimated correlation is assessed by a permutation test that maintains the overall structure of the pedigree. Further, temporal trends in fertility within this population are accounted for. Applying these methods to the S-Leut Hutterites yields a correlation in effective family size of 0.29 between couples and their sons and 0.18 between couples and their daughters, with empirical P<1x10-6 and P=.0041, respectively. Similar results were obtained for completed families (0.31 between couples and their sons and 0.23 between couples and their daughters; empirical P<1x10-6 and P=.00059, respectively). We interpret these results as indicating a significant genetic component to reproductive fitness in the Hutterites.
authors.affiliation: Department of Medicine, University of Chicago, Chicago, IL, 60637, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Pluzhnikov
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Nolan
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Tan
authors.forename: Mary Sara
authors.initials: MS
authors.lastname: McPeek
authors.forename: Carole
authors.initials: C
authors.lastname: Ober
mesh_terms: D000328:Adult; D005191:Family Characteristics; D005260:Female; D006801:Humans; D016901:Intergenerational Relations; D008297:Male; D010375:Pedigree; D012098:Reproduction / Q000235:genetics*; D044465:White People / Q000235:genetics*