SAMPLING THEORY FOR CYTONUCLEAR DISEQUILIBRIA

We examine the statistical properties of cytonuclear disequilibria wit hin a system including one diploid nuclear locus and one haploid cytop lasmic locus, each with two alleles. The results provide practical gui delines for the design and interpretation of cytonuclear surveys seeki ng to utilize the novel evolutionary information recorded in the obser ved pattern of cytonuclear associations. Important applications includ e population studies of nuclear allozymes in conjunction with genes fr om mitochondria, chloroplasts, or cytoplasmically inherited microorgan isms. Our attention focuses on the allelic and genotypic disequilibria , which respectively measure the nonrandom associations between the cy totypes and the nuclear alleles and genotypes. We first derive the max imum likelihood estimators and their approximate large sample variance s for each disequilibrium measure. These are each in turn used to set up an asymptotic test of the null hypothesis of no disequilibrium. We then calculate the minimum sample sizes required to detect the disequi libria under specified alternate hypotheses. The work also incorporate s the deviation from Hardy-Weinberg equilibrium at the nuclear locus, which can significantly affect the results. The practical utility of t his new sampling theory is illustrated through applications to two nuc lear-mitochondrial data sets.