A May 2010 Science paper showing that the most genetically fit cow-pea weevils have fewer deleterious genetic mutations in their genomes than their less fit counterparts was retracted yesterday (September 1) by the authors because of flaws in their statistical analysis.
The results seemed to answer a long-standing question of how genetic variation can persist in a population even though individuals are under constant pressure from natural and sexual selection to weed out deleterious mutations, according to a news report from the University of Zurich in Switzerland. The researchers contended that their results offered further support of the hypothesis that genetic mutations are constantly appearing in populations, and that individuals with the fewest bad mutations will produce the most fit offspring.
The statistical analysis that led to the conclusions was flawed because the authors failed to acknowledge that predicted weevil offspring phenotypes and observed offspring phenotypes are not independent variables. A technical comment that details the specific flaws was published alongside the retraction. The authors realized the error and when they reanalyzed their data, they “found a similar, but weaker, overall effect,” they wrote in the retraction. “Because the published correlation values are in error, we retract our original Report.” The revised data analysis, which shows little effect on fitness due to mutation, suggests that some other mechanism may instead be responsible for maintaining genetic variation in weevil populations.