As compared with the standard approach of analyzing sequences from each patient independently , the HPM provides more efficient estimation of evolutionary parameters such as nucleotide substitution rates and d ( N ) /d ( S ) rate ratios , as shown by significant shrinkage of the estimator variance .
O O O O O O O O O O O B-OrganismTaxon O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O