title: Quantitative variation in sets of triplets and quadruplets: a simulation.
abstract: A computer simulation was devised to generate realistic but large samples of twins, triplets, and quadruplets in each of the possible zygosity types. To validate the simulation, I used formulas proposed by Richter and Geisser (1960) to predict the mean value of the sum of squared deviations in each of three types of triplets and five types of quadruplets and to predict the distributions of the sums of squares in pure types (e.g., monozygotic and trizygotic triplets). Use of the formulas to predict distributions in sets of mixed type or to diagnose zygosity requires more advanced mathematical methods, but the simulation readily generates standard populations of all types of sets. If large enough numbers of real triplets or quadruplets ever become available to permit useful comparison with these standards or with the formulas, developmental peculiarities of the higher-order births might be revealed.
authors.affiliation: National Institute of Mental Health, US Public Health Service, Bethesda, MD, USA.
authors.forename: G
authors.initials: G
authors.lastname: Allen
mesh_terms: D003198:Computer Simulation; D014644:Genetic Variation; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008962:Models, Theoretical; D011783:Quadruplets / Q000235:genetics*; D014310:Triplets / Q000235:genetics*; D014427:Twins / Q000235:genetics*; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics