Over 75% of Caucasians from North and Northeastern Brazil would have over 10% native African genes, according to this particular study. Even in Southeastern and Southern Brazil, regions which received large waves of European immigration beginning in the 1820s and growing strongly , 49% of the Caucasian population would have over 10% native African genes, according to that study. Thus, 86% of Brazilians would have at least 10% of genes that came from Africa. The researchers however were cautious about its conclusions: "Obviously these estimates were made by extrapolation of experimental results with relatively small samples and, therefore, their confidence limits are very ample". A new autosomal study from 2011, also led by Sérgio Pena, but with nearly 1000 samples this time, from all over the country, shows that in most Brazilian regions most Brazilians "whites" are less than 10% African in ancestry, and it also shows that the "pardos" are predominantly European in ancestry, the European ancestry being therefore the main component in the Brazilian population, in spite of a very high degree of African ancestry and significant Native American contribution. Other autosomal studies (see some of them below) show a European predominance in the Brazilian population.