Lunch Seminar MESIO UPC-UB

Speaker:  Jan Graffelman
                 Department of Statistics and Operations Research, UPC

Title:        The Statistics of Hardy-Weinberg Equilibrium

Abstract:
The Hardy-Weinberg law is a cornerstone principle of modern genetics. The law is more than a century old, and was independently stated in 1908 by the English mathematician Godfrey Hardy and the German physician Wilhelm Weinberg. The law states that, in the absence of disturbing factors (migration, differential survival and others) allele and genotype frequencies in a biological population will achieve equilibrium values within one generation and remain stable afterwards. The latter condition is known as Hardy-Weinberg equilibrium (HWE).

The principle is still relevant today, as testing markers for HWE is a standard step in almost all genetic studies. It is known that deviation from equilibrium is often associated with genotyping errors (misclassification of homozygotes as heterozygotes or the reverse), and equilibrium testing is an effective device to detect such errors. However, disequilibrium can also arise from other causes.

Moreover, Hardy-Weinberg equilibrium is typically assumed in many other statistical procedure that use genetic marker data, such as gene-disease association studies, relatedness investigations, and others. The HWE law has been a topic of intense research, and there are hundreds of research papers dedicated to it. Research related to the principle continues, as new types of genetic data arise. Pearson's chi-square test has been the most popular procedure to test genetic markers for equilibrium for decades, though nowadays computer-intensive exact procedures have become more and more popular.

In this talk I will explain some basic genetics, address the issue of statistically testing markers for Hardy-Weinberg equilibrium in large genomic databases, and comment upon recent work related to markers that reside on the X chromosome.