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S Karlin

Publications and source records attributed to S Karlin.

At least 127 records · Page 7Linked to original sources
PubMed1984

Permutation methods for the structured exploratory data analysis (SEDA) of familial trait values.

A collection of functions that contrast familial trait values between and across generations is proposed for studying transmission effects and other collateral influences in nuclear families. Two classes of structured exploratory data analysis (SEDA) statistics are derived from ratios of these functions. SEDA-functionals are the empirical cumulative distributions of the ratio of the two contrasts computed within each family. SEDA-indices are formed by first averaging the numerator and denominator contrasts separately over the population and then forming their ratio. The significance of SEDA results are determined by a spectrum of permutation techniques that selectively shuffle the trait values across families. The process systematically alters certain family structure relationships while keeping other familial relationships intact. The methodology is applied to five data examples of plasma total cholesterol concentrations, reported height values, dermatoglyphic pattern intensity index scores, measurements of dopamine-beta-hydroxylase activity, and psychometric cognitive test results.

Adolescent↗
PubMed1983

Structured exploratory data analysis (SEDA) of finger ridge-count inheritance: I. Major gene index, midparental correlation, and offspring-between-parents function in 125 south Indian families.

Fourteen dermatoglyphic traits measured on 125 Velanadu Brahmin families were analyzed for mode of inheritance using three Structured Exploratory Data Analysis (SEDA) statistics: the major gene index, the offspring between parents function, and the traditional midparental correlation coefficient. Since the traits are integer valued with restricted ranges of variation, we simulated various transmission models with discrete expression to better understand the nature of the SEDA statistics for such variables. In addition, permutation procedures were employed to aid the interpretation of the SEDA results. These analyses suggest that corresponding homologous fingers on the left and right hands exhibit similar transmission characteristics. The relationship of the parent and child total ridge-counts of the two hands separately, as well as their combined total, virtually simulate complete Galtonian blending inheritance. Results for the individual digital ridge-counts as well as the pattern-intensity-index variable also suggest a multifactorial mode of transmission or possibly one involving several genes.

Dermatoglyphics↗
PubMed1983

Structured exploratory data analysis (SEDA) of finger ridge-count inheritance: II. Association arrays in parent-offspring and sib-sib pairs.

Familial similarity of the dermatoglyphic trait values of finger ridge-count scores and pattern intensity index is examined for 125 nuclear families from the Velanadu Brahmin population of Southern India by the method of association arrays. This methodology assesses parent-offspring and sibship similarity through a collection of measures of dependence that is sensitive to a variety of nonlinear trends and stochastic relationships between trait values. The method is used in conjunction with various weights to determine the relationship between family size and the level and form of dependence. These analyses reveal that siblings are most strongly associated for ridge-counts of the middle digit and less associated for the thumb and fifth digit ridge-counts. Further, sibship similarity for ridge-counts increases with family size for the thumb and fifth digit but remains relatively constant over all family sizes for the middle finger. Family size effects are also observed for total ridge-counts of the left hand, right hand, and both hands combined, and for the pattern intensity index. These effects of family size may be due to the most pronounced changes occurring in the amniotic environment between the first and second pregnancy, which are most strongly manifested in the sibship associations of smaller families.

Dermatoglyphics↗
PubMed1983

New approaches for computer analysis of nucleic acid sequences.

A new high-speed computer algorithm is outlined that ascertains within and between nucleic acid and protein sequences all direct repeats, dyad symmetries, and other structural relationships. Large repeats, repeats of high frequency, dyad symmetries of specified stem length and loop distance, and their distributions are determined. Significance of homologies is assessed by a hierarchy of permutation procedures. Applications are made to papovaviruses, the human papillomavirus HPV, lambda phage, the human and mouse mitochondrial genomes, and the human and mouse immunoglobulin kappa-chain genes.

Animals↗
PubMed1983

On the optimal sex ratio.

The equilibrium structures for various multiallele sex-determining genetic models of panmictic populations with sex expression depending on the genotypes of either the zygote or a parent are described. Even-sex-ratio equilibrium surfaces can exist apart from equilibrium points having coincident male and female allelic frequency sets. The latter (symmetric) equilibrium states entail biased sex ratios. A stable symmetric equilibrium and an even-sex-ratio equilibrium segregating the same alleles cannot coexist. The tendency to evolve toward an even-sex ratio is embodied by the following optimality property: starting from an equilibrium having a biased sex ratio, mutant sex-determining alleles can accumulate only in the case in which in the augmented system all attainable equilibrium states have a sex ratio closer to one to one.

Alleles↗
PubMed1983

Association arrays in assessing forms of dependencies between bivariate random variables.

The bivariate distribution of pairs of random variables (X,Y) is said to be associated with respect to the classes of functions [unk] and [unk] if the product-moment correlation r[Phi(X),Psi(Y)] >/= 0 for all Phi euro [unk] and Psi euro [unk]. In the case in which both [unk] = [unk] = [unk](*) consist of all increasing functions, then the bivariate distribution of (X,Y) is said to be positive quadrant dependent. To apply the concept to data, I examine the correlations for classes of extremal functions that span by positive combinations the totality of functions Phi euro [unk] and Psi euro [unk] to investigate whether the pair of random variables (X,Y) are associated with respect to [unk] and [unk] and to assess the relative degree (or strength) of association when comparing two sets of random variables (X,Y) and (Z,W).

Journal Article↗
PubMed1983

Path analysis in genetic epidemiology: a critique.

Path analysis, a form of general linear structural equation models, is used in studies of human genetics data to discern genetic, environmental, and cultural factors contributing to familial resemblance. It postulates a set of linear and additive parametric relationships between phenotypes and genetic and cultural variables and then essentially uses the assumption of multivariate normality to estimate and perform tests of hypothesis on parameters. Such an approach has been advocated for the analysis of genetic epidemiological data by D. C. Rao, N. Morton, C. R. Cloninger, L. J. Eaves, and W. E. Nance, among others. This paper reviews and evaluates the formulations, assumptions, methodological procedures, interpretations, and applications of path analysis. To give perspective, we begin with a discussion of path analysis as it occurs in the form of general linear causal models in several disciplines of the social sciences. Several specific path analysis models applied to lipoprotein concentrations, IQ, and twin data are then reviewed to keep the presentation self-contained. The bulk of the critical discussion that follows is directed toward the following four facets of path analysis: (1) coherence of model specification and applicability to data; (2) plausibility of modeling assumptions; (3) interpretability and utility of the model; and (4) validity of statistical and computational procedures. In the concluding section, a brief discussion of the problem of appropriate model selection is presented, followed by a number of suggestions of essentially model-free alternative methods of use in the treatment of complex structured data such as occurs in genetic epidemiology.

Asian↗
PubMed1982

Association arrays for the study of familial height, weight, lipid, and lipoprotein similarity in three West Coast populations.

A more refined understanding of familial similarity may be achieved through a collection of measures of dependence that is sensitive to a variety of nonlinear trends ans stochastic relationships between trait values. Parent-offspring, spouse, and sibling similarities are examined by association arrays that assess dependence between variables for appropriate classes of functions (e.g., the class of all increasing functions). The methodology is applied to height, weight, lipid, and lipoprotein variables collected in nuclear families at the Seattle, Stanford, and La Jolla Lipid Research Clinics. Among the results obtained using association arrays, there is the suggestion that spouse similarity for standardized weight is strongest for functions emphasizing the higher values of the wives' weight independent of the husbands' weight, and that sibling similarity for high density lipoprotein cholesterol concentrations appears strongest for functions emphasizing the higher values of the siblings. The results deduced from the method of association arrays are compared and contrasted with those obtained from standard correlations.

Adolescent↗
PubMed1982

Association arrays for comparing familial total cholesterol, high density lipoprotein cholesterol, and triglyceride similarity in the Israeli population by country of origin.

The method of association arrays is applied to plasma total cholesterol, triglyceride, and high density lipoprotein cholesterol concentrations measured for 2485 young men and women aged 17-18 years and living in Jerusalem, and for their parents. These triad families are divided into five groups according to whether they were of mixed "origins." Stronger associations are present for all lipid and lipoprotein cholesterol variables in Asian and African families relative to families of other origins, possibly reflecting the more disciplined life-style patterns in these families relative to other families. Parent and offspring values exhibit positive association for all lipid variables in all groups. Patterns of familial similarity revealed by the association arrays are discussed in relation to historic and cultural differences among groups.

Adolescent↗
PubMed1982

Analysis of biochemical genetic data on Jewish populations. III. The application of individual phenotype measurements for population comparisons.

Individual phenotypic data on six blood markers and six enzyme polymorphisms in seven Jewish and two non-Jewish populations were subjected to a comparative statistical analysis. A set of functionals defined with respect to the individual biochemical profiles was used to investigate the following problems: (1) What are the distributional characteristics of various types of individual heterozygosity measures (for blood and enzyme loci) within and across populations? (2) Is the observed phenotypic variation in agreement with what might be expected if the loci were independent? (3) What proportion of the characteristics can be explained by reference to population structure and historical data? Average total heterozygosity of blood and protein loci was highest in the Iraqi population and lowest in the Yemenite. The differences among the other populations were not significant. The highest cumulative recessive homozygosity of blood markers occurs in Yemenites and Samaritans. No association was present between total blood and protein heterozygosity. Applications of these ideas and techniques to the study of multilocus genetic organization are discussed.

Blood Group Antigens↗
PubMed1981

Sibling and parent--offspring correlation estimation with variable family size.

A method for estimating intrafamilial correlations under variable family sizes involving weightings of paired data points is introduced. Classical methods of intrafamilial correlation estimation and those in current use are outlined and critically analyzed. Extensions of the proposed estimation method to more general data structures are delineated.

Family↗
PubMed1981

Preferential mating in symmetric multilocus systems.

A class of multilocus models that incorporate both preferential mating and viability selection is studied. Symmetry in alleles is supposed, resulting in the phenotypes being dependent only on the location of heterozygous loci. Otherwise, an arbitrary number of loci, number of alleles per locus, and arbitrary recombination schemes, viability parameters, and preferential mating pattern are allowed. The conditions for stability of a central polymorphism, c(*), are indicated and interpreted. Mating and viability parameters enter as one combined quantity for each phenotypic class, which represents a generalized fitness. The effect on stability of c(*) of increasing the number of alleles per locus and the number of loci requires the formulation to be set in terms of frequency-dependent preference parameters.

Journal Article↗