Brazilian geneticist Sérgio Pena has criticised American scholar Edward Telles for lumping "pretos" and "pardos" in the same category. According to him, "the autosomal genetic analysis that we have performed in non-related individuals from Rio de Janeiro shows that it does not make any sense to put "pretos" and "pardos" in the same category". As most pardos are primarily of European ancestry, Pena questioned studying them together with pretos, who are primarily of African ancestry. For example, an autosomal genetic study of students in a school in the poor periphery of Rio de Janeiro found that the "pardos" among the students were found to be on average more than 40% European in ancestry. Before testing, the students identified (when asked) as ⅓ European, ⅓ African and ⅓ Native American.