Recently, an article by Simoni et al. (2000), who used (i) SAAP analysis to analyze the population frequencies of mtDNA haplogroups and (ii) AIDA analysis to examine both the frequency and the sequence similarity of truncated mtDNA sequences, appeared in this Journal. The main outcome of their study was that "the overall patterns of mtDNA diversity appear to be poorly significant in Europe." The raw data comprised 2,619 hypervariable segment I (HVS-I) sequences (denoted as "HVR-I" [hypervariable region I] sequences by Simoni et al. ) that were obtained from 36 regions or populations of Europe, the Near East, and the Caucasus and that were collected from both the literature and unpublished sources. Simoni et al. ostensibly grouped the HVS-I sequences according to haplogroup motifs proposed elsewhere (Richards et al. 1998), and they reported the resulting frequencies for each region/population in table 3 in their study. We have checked the input data displayed in table 3 and have found serious technical errors affecting numerous entries. More critically, the mtDNA categories that they report correspond neither to their own criteria nor to the haplogroup definitions established in the literature (to which they refer). Furthermore, their decision to truncate HVS-I information (and to disregard RFLP information) renders these data inadequate to differentiate even African and East Asian sequences from European sequences in many cases.