Does Bonferroni correction “rescue” the deviation from Hardy-Weinberg equilibrium?

Abstract

The application of Bonferroni correction (BC) has been constantly controversial; nevertheless, in forensic population genetics research, it is common to apply it to Hardy-Weinberg equilibrium (HWE) tests referring to multiple loci. This letter aimed to discuss the problems of applying BC to HWE tests involving multiple loci by surveying population genetics research studies published over the last 10 years (2009–2019) from two major forensic genetic journals: Forensic Science International: Genetics (FSIG) and the International Journal of Legal Medicine (IJLM). The results showed that there was no uniform standard of whether to apply BC to HWE tests or not, and researchers commonly did not provide any explanation for the observation of deviations from HWE. Despite its widespread use in population genetics, BC may not guarantee a prudent result due to an irrelevant null hypothesis, reluctance to reject the null hypothesis, different interpretations of identical p-values, and inflated type Ⅱ error. We recommended a notable two-step approach suggested by Waples to evaluate the results of HWE tests: 1) identifying causes of departures from HWE and 2) evaluating the biological consequences of HW departures. In addition, for forensic researchers, we suggested that if a certain degree of deviation from HWE does occur, the first step to take should involve checking the technique and genotyping results carefully rather than recklessly using BC. In conclusion, according to the purpose of forensic population research, applying BC to HWE tests is unnecessary; rather, an unadjusted α should be used. BC does not “rescue” the deviation from HWE. To “rescue” it indeed, directly discussing the possible explanation for each departure from HWE and simply describing what has been done sequentially and why should be enough for readers to reach a reasonable conclusion even without the help of Bonferroni methods.