title: Genetic regulation of plasma and red blood cell magnesium concentration in man. II. Segregation analysis.
abstract: A previous paper in this series reported that genetic factors play a major role in the familial transmission of plasma (P) and red blood cell (RBC) magnesium (Mg) concentrations. We report here the results of commingling analysis based on a random sample of unrelated individuals, and complex segregation analysis of a random sample of nuclear families. For RBC Mg, there is evidence for a mixture of two distributions, but not for three. For P Mg, there is no evidence for commingling. Complex segregation analysis under a mixed model yielded significant support for a major gene effect on RBC Mg, but not on P Mg. Parameter estimates indicated that the data are compatible with a rather common major gene (q = .23) for elevated RBC Mg, roughly 5% of the population being homozygotes for this gene, that the nonfamilial factors account for a small fraction of the total variance, and that the overlap of distributions of homozygotes is not large.
mesh_terms: D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005826:Genetics, Medical; D006720:Homozygote; D006801:Humans; D008274:Magnesium / Q000097:blood*; D008297:Male; D008540:Meiosis; D008957:Models, Genetic; D010375:Pedigree; D010641:Phenotype; D011336:Probability
chemical_list: D008274:Magnesium