Ward P J
Department of Biostatistics, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104.
Genetics. 1990 Jul;125(3):655-67. doi: 10.1093/genetics/125.3.655.
Recent developments have related quantitative trait expression to metabolic flux. The present paper investigates some implications of this for statistical aspects of polygenic inheritance. Expressions are derived for the within-sibship genetic mean and genetic variance of metabolic flux given a pair of parental, diploid, n-locus genotypes. These are exact and hold for arbitrary numbers of gene loci, arbitrary allelic values at each locus, and for arbitrary recombination fractions between adjacent gene loci. The within-sibship, genetic variance is seen to be simply a measure of parental heterozygosity plus a measure of the degree of linkage coupling within the parental genotypes. Approximations are given for the within-sibship phenotypic mean and variance of metabolic flux. These results are applied to the problem of attaining adequate statistical power in a test of association between allozymic variation and inter-individual variation in metabolic flux. Simulations indicate that statistical power can be greatly increased by augmenting the data with predictions and observations on progeny statistics in relation to parental allozyme genotypes. Adequate power may thus be attainable at small sample sizes, and when allozymic variation is scored at a only small fraction of the total set of loci whose catalytic products determine the flux.
近期的研究进展已将数量性状表达与代谢通量联系起来。本文探讨了这一联系对多基因遗传统计学方面的一些影响。在给定一对亲代二倍体n位点基因型的情况下，推导了同胞间代谢通量的遗传均值和遗传方差的表达式。这些表达式是精确的，适用于任意数量的基因位点、每个位点的任意等位基因值以及相邻基因位点之间的任意重组率。同胞间的遗传方差被视为仅仅是亲代杂合性的一种度量加上亲代基因型内连锁耦合程度的一种度量。给出了同胞间代谢通量表型均值和方差的近似值。这些结果被应用于在检验同工酶变异与代谢通量个体间变异之间的关联时获得足够统计功效的问题。模拟表明，通过用与亲代同工酶基因型相关的子代统计量的预测和观察来扩充数据，可以大大提高统计功效。因此，在小样本量情况下，以及当同工酶变异仅在其催化产物决定通量的全部位点中的一小部分位点上进行评分时，也可能获得足够的功效。
