All these towns are settled predominantly by Brazilians of German or Italian descent and are usually very small. In the 19th century, many German and Italian immigrants were attracted by the Brazilian government to populate inhospitable areas in the South of the country. Slavery was banned in these settlements and many of these areas remained settled exclusively by European immigrants and their descendants. Until quite recently, many of these towns have been relatively isolated areas, and German or Italian cultural traditions are still very strong, with many of their inhabitants being able to speak German or Italian, especially in the more rural areas. The Brazilian towns with the largest percentages of whites are the following:   The Brazilian towns with the lowest percentages of whites are located in Northern and Northeastern Brazil and are also small. The genes can reveal from what part of the world the oldest ancestors of the paternal and maternal line of a person came from. The mitochondrial DNA (mtDNA) is present in all human beings and passed down through the maternal line, i.e. the mother of a mother of a mother etc. The Y chromosome is present only in males and passed down through the paternal line, i.e., the father of a father of a father etc. The mitochondrial DNA and Y chromosome suffer only minor mutations through centuries, thus can be used to establish the paternal line in males (because only males have the Y chromosome) and the maternal line in both males and females. According to a genetic study about Brazilians (based upon about 200 samples), on the paternal side, 98% of the white Brazilian Y Chromosome comes from a European male ancestor, only 2% from an African ancestor and there is a complete absence of Amerindian contributions. On the maternal side, 39% have European Mitochondrial DNA, 33% Amerindian and 28% African female ancestry. This, considering the facts that the slave trade was effectively suppressed in 1850, and that the Amerindian population had been reduced to small numbers even earlier, shows that at least 61% of white Brazilians had at least one ancestor living in Brazil before the beginning of the Great Immigration. This analysis, however, only shows a small fraction of a person's ancestry (the Y Chromosome comes from a single male ancestor and the mtDNA from a single female ancestor, while the contributions of the many other ancestors is not specified). According to another genetic research (based upon about 200 samples again) over 75% of caucasians from North, Northeast and Southeast Brazil would have over 10% Sub-Saharan African genes, and that this would also be the case with Southern Brazil for 49% of the caucasian population.