Journal of Heredity Advance Access first published online on May 26, 2007
This version published online on August 3, 2007
Journal of Heredity, doi:10.1093/jhered/esm020
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Hardy–Weinberg Expectations in Canine Breeds: Implications for genetic studies
From the Centre for Integrated Genomic Medical Research, Stopford Building, The University of Manchester, Manchester M13 9PT, UK (Short, Kennedy, and Ollier); the Veterinary Faculty, The University of Liverpool, Liverpool L69 7ZJ, UK (Barnes); the WALTHAM Centre for Pet Nutrition, Freeby Lane, Leicestershire LE14 4RT, UK (Fretwell and Jones); and the School of Epidemiology and Health Sciences, Stopford Building, The University of Manchester, Manchester M13 9PT, UK
Address correspondence to A. D. Short at the address above, or e-mail: andrea.Short{at}manchester.ac.uk.
Hardy–Weinberg equilibrium (HWE) is a useful indicator of genotype frequencies within a population and whether they are based on a valid definition of alleles and a randomly mating sample. HWE assumes a stable population of adequate size without selective pressures and is used in human genetic studies as a guide to data quality by comparing observed genotype frequencies to those expected within a population. The calculation of genetic associations in case–control studies assume that the population is "in HWE." Canine breed populations deviate away from many of the criteria for HWE, and if genetic markers are not in HWE, conventional statistical analysis cannot be performed. To date, little attention has been paid as to whether genetic markers in dog breeds are distributed in compliance to HWE. In this study, 109 single-nucleotide polymorphisms (SNPs) were genotyped from 13 genes in a cohort of 894 dogs encompassing 33 breeds. Analysis of the entire cohort of dogs revealed a significant deviation away from HWE for all SNPs tested (P < 0.00001); analysis of the cohort stratified by breed and subbreed indicated that the majority of the markers complied with HWE expectation. This suggests that canine case–control association studies will be valid if performed within defined breeds.
Corresponding Editor: Steven Hannah
The symposium paragraph for this article has been inserted.
The symposium has been moved to after the reference section.
This paper was delivered at the 3rd International Conference on the Advances in Canine and Feline Genomics, School of Veterinary Medicine, University of California, Davis, CA, August 3–5, 2006.