Browsing by Author "Graffelman, Jan"

A bayesian test for HardyWeinberg equilibrium of biallelic Xchromosomal markers
Puig Oriol, Xavier; Ginebra Molins, Josep; Graffelman, Jan (201707)
Article
Open AccessThe X chromosome is a relatively large chromosome, harboring a lot of genetic information. Much of the statistical analysis of Xchromosomal information is complicated by the fact that males only have one copy. Recently, ... 
A Compositional Approach to Allele Sharing Analysis
Galván Femenía, Iván; Graffelman, Jan (Springer, 2016)
Part of book or chapter of book
Restricted access  publisher's policyRelatedness is of great interest in populationbased genetic association studies. These studies search for genetic factors related to disease. Many statistical methods used in populationbased genetic association studies ... 
A genomewide study of Hardy–Weinberg equilibrium with next generation sequence data
Graffelman, Jan; Jain, Deepti; Weir, B.S. (20170403)
Article
Open AccessStatistical tests for Hardy–Weinberg equilibrium have been an important tool for detecting genotyping errors in the past, and remain important in the quality control of next generation sequence data. In this paper, we ... 
A logratio biplot approach for exploring genetic relatedness based on identity by state
Graffelman, Jan; Galván Femenía, Iván; de Cid, Rafael; Barceló Vidal, Carles (20190424)
Article
Open AccessThe detection of cryptic relatedness in large populationbased cohorts is of great importance in genome research. The usual approach for detecting closely related individuals is to plot allele sharing statistics, based on ... 
An application of the isometric logratio transformation in relatedness research
Graffelman, Jan; Galván Femenía, Iván (Springer, 2016)
Part of book or chapter of book
Restricted access  publisher's policyAbstract Genetic marker data contains information on the degree of relatedness of a pair of individuals. Relatedness investigations are usually based on the extent to which alleles of a pair of individuals match over a set ... 
Bayesian model selection for the study of HardyWeinberg proportions and homogeneity of gender allele frequencies
Puig Oriol, Xavier; Ginebra Molins, Josep; Graffelman, Jan (20190529)
Article
Restricted access  publisher's policyStandard statistical tests for HardyWeinberg equilibrium assume the equality of allele frequencies in the sexes, whereas tests for the equality of allele frequencies in the sexes assume Hardy–Weinberg equilibrium. This ... 
Contributions to the multivariate Analysis of Marine Environmental Monitoring
Graffelman, Jan (Universitat Politècnica de Catalunya, 20000912)
Doctoral thesis
Open AccessThe thesis parts from the view that statistics starts with data, and starts by introducing the data sets studied: marine benthic species counts and chemical measurements made at a set of sites in the Norwegian Ekofisk oil ... 
Correlation between tobacco control policies, consumption of rolled tobacco and ecigarettes, and intention to quit conventional tobacco, in Europe
LidónMoyano, Cristina; Martín Sánchez, Juan Carlos; Saliba, Patrick; Graffelman, Jan; Martínez Sánchez, Jose Maria (20160217)
Article
Open Access 
Exact inference for HardyWeinberg proportions with missing genotypes: single and multiple imputation
Graffelman, Jan; Nelson, S.; Gogarten, S.M.; Weir, B.S. (20150915)
Article
Open AccessThis paper addresses the issue of exacttest based statistical inference for HardyWeinberg equilibrium in the presence of missing genotype data. Missing genotypes often are discarded when markers are tested for HardyWeinberg ... 
Exploration of geochemical data with compositional canonical biplots
Graffelman, Jan; Pawlowsky Glahn, Vera; Egozcue Rubí, Juan José; Buccianti, A. (20180725)
Article
Restricted access  publisher's policyThe study of the relationships between two compositions is of paramount importance in geochemical data analysis. This paper develops a compositional version of canonical correlation analysis, called CoDACCO, for this ... 
Exploring Diallelic genetic markers: The Hardy Weinberg package
Graffelman, Jan (201503)
Article
Open AccessTesting genetic markers for HardyWeinberg equilibrium is an important issue in genetic association studies. The HardyWeinberg package o ers the classical tests for equilibrium, functions for power computation and for the ... 
Factor Analysis
Graffelman, Jan (Wiley, 2013)
Part of book or chapter of book
Restricted access  publisher's policyFactor analysis is a multivariate statistical method for data reduction that originated in psychometrics and has found applications in many branches of science. The method aims to describe the correlation structure between ... 
Graphics for relatedness research
Galván Femenía, Iván; Graffelman, Jan; Barceló Vidal, Carles (Wiley, 20170403)
Article
Open AccessStudies of relatedness have been crucial in molecular ecology over the last decades. Good evidence of this is the fact that studies of population structure, evolution of social behaviours, genetic diversity and quantitative ... 
LinearAngle correlation plots: New graphs for revealing correlation structure
Graffelman, Jan (20130327)
Article
Restricted access  publisher's policyIn multivariate graphics, correlations between variables are often approximated by the cosines of the angles between vectors. In practice, it is difficult to reliably estimate correlations from such displays by eye. In ... 
Multiallelic exact tests for HardyWeinberg equilibrium that account for gender
Graffelman, Jan; Weir, B.S. (Wiley, 201801)
Article
Open AccessStatistical tests for Hardy–Weinberg equilibrium are important elementary tools in genetic data analysis. Xchromosomal variants have long been tested by applying autosomal test procedures to females only, and gender is ... 
On the testing of HardyWeinberg proportions and equality of allele frequencies in males and females at biallelic genetic markers
Graffelman, Jan; Weir, B.S. (20180201)
Article
Open AccessStandard statistical tests for equality of allele frequencies in males and females and tests for HardyWeinberg equilibrium are tightly linked by their assumptions. Tests for equality of allele frequencies assume HardyWeinberg ... 
Statistical inference for HardyWeinberg proportions in the presence of missing genotype information
Graffelman, Jan; Sánchez, Milagros; Cook, Samantha; Moreno, Victor (20131231)
Article
Open AccessIn genetic association studies, tests for HardyWeinberg proportions are often employed as a quality control checking procedure. Missing genotypes are typically discarded prior to testing. In this paper we show that ... 
Testing for Hardy–Weinberg equilibrium at biallelic genetic markers on the X chromosome
Graffelman, Jan; Weir, B.S. (20160413)
Article
Open AccessTesting genetic markers for Hardy–Weinberg equilibrium (HWE) is an important tool for detecting genotyping errors in largescale genotyping studies. For markers at the X chromosome, typically the ¿2 or exact test is applied ... 
The number of markers in the HapMap project: some notes on Chisquare and Exact tests for HardyWeinberg equilibrium
Graffelman, Jan (20100514)
Article
Restricted access  publisher's policy