genome-wide association studies In genomics, a genome-wide association study (GWA study, or GWAS), is an observational study of a genome-wide set of genetic variants in different individuals to see if any variant is associated with a trait. GWA studies typically focus on assoc ...

, genome-wide significance (abbreviated GWS) is a specific threshold for determining the

statistical significance In statistical hypothesis testing, a result has statistical significance when a result at least as "extreme" would be very infrequent if the null hypothesis were true. More precisely, a study's defined significance level, denoted by \alpha, is the ...

of a reported

association Association may refer to: *Club (organization), an association of two or more people united by a common interest or goal *Trade association, an organization founded and funded by businesses that operate in a specific industry *Voluntary associatio ...

between a given

single-nucleotide polymorphism In genetics and bioinformatics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a ...

(SNP) and a given trait. The most commonly accepted threshold is ''p'' < 5 × 10⁻⁸, which is based on performing a

Bonferroni correction In statistics, the Bonferroni correction is a method to counteract the multiple comparisons problem. Background The method is named for its use of the Bonferroni inequalities. Application of the method to confidence intervals was described by ...

for all the independent common SNPs across the

human genome The human genome is a complete set of nucleic acid sequences for humans, encoded as the DNA within each of the 23 distinct chromosomes in the cell nucleus. A small DNA molecule is found within individual Mitochondrial DNA, mitochondria. These ar ...

. If a ''p''-value is found to be lower than this threshold in a genome-wide association study, the

null hypothesis The null hypothesis (often denoted ''H''0) is the claim in scientific research that the effect being studied does not exist. The null hypothesis can also be described as the hypothesis in which no relationship exists between two sets of data o ...

of no true SNP-association will typically be rejected. However, there has been some criticism of this threshold, with a 2012 study suggesting that a significant number of associations with ''p''-values just above this threshold are genuine, replicable associations. The authors of this study concluded that their finding "...suggests a possible relaxation in the current GWS threshold." More recently, it has been suggested that the conventional threshold should be modified to take into account the increasing prevalence of low-

frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

genetic variants in genome-wide association studies.

References

Statistical genetics Statistical hypothesis testing {{Genetics-stub