 However, it is not enough to study variation alone because the two main forms of linked selection, background and hitchhiking, produce a loss in diversity, and the models both predict similar results in genomic regions of high recombination.The relative influence of these two effects is not yet well understood, though methods have been developed for differentiating between the two effects.One technique is to compare levels of nucleotide diversity in regions of low recombination, where the models differ appreciably in their predictions.