Brazil is a multiethnic society, which means that it is home to people of many ethnic origins, and there is no correlation between one's stock and their Brazilian identity.

As a result, the degree to which Brazilian citizens identify with their ancestral roots varies significantly depending on the individual, the region of the country, and the specific ethnic origins in question.

A foreigner can apply for Brazilian citizenship after living for four uninterrupted years in Brazil and being able to speak Portuguese language.

A native person from an official Portuguese language country (Portugal, Angola, Mozambique, Cape Verde, São Tomé and Príncipe, Guinea Bissau, Equatorial Guinea, and East Timor) can request the Brazilian nationality after only 1 uninterrupted year living in Brazil.

[1] Brazilians are mostly descendants of Portuguese settlers, post-colonial immigrant groups, enslaved Africans and Brazil's indigenous peoples.

The main historic waves of immigration to Brazil have occurred from the 1820s well into the 1970s, most of the settlers were Portuguese, Italians, Germans, and Spaniards, with significant minorities of Japanese, Poles, Ukrainians and Levantine Arabs.

[6] The first inhabitants of what would become Brazil were people whose ancestry can be traced back to Asian populations that crossed the Bering Strait, passing from Siberia to the Americas.

With the arrival of the Portuguese in present-day Brazil, in 1500, a significant part of the indigenous population perished, mainly due to contamination by Eurasian diseases to which the Indians had no biological immunity, such as smallpox, measles, yellow fever or flu.

In this context, many Portuguese settlers had relationships with indigenous women, whose descendants make up a large part of the current Brazilian population.

[18] At that time, Brazil was the largest producer of sugar in the world (specifically the northeastern captaincies of Pernambuco and Bahia), and this economic growth attracted many Portuguese immigrants.

Gold and diamond deposits were discovered in Brazil from 1690 onwards, which generated an increase in the importation of slaves, to supply labor in mining.

According to Historians James Horn and Philip D. Morgan, between 1500 and 1820, 605,000 Portuguese emigrated to Brazil, against 3.2 million Africans brought, a number 5 times greater.

[32][33][34][35] Another model of immigration encouraged by the Brazilian government was aimed at agricultural colonization, mainly in the South of the country, where access to small rural properties for European immigrants was facilitated, mainly as a way of filling demographic voids and overcoming the constant threats of food shortages in Brazil.

[36][37][38][33][35][34] However, many of these immigrants arrived spontaneously, without any help from the Brazilian government, and were attracted by the increase in urban dynamism, mainly in the Southeast region, largely linked to the surplus of wealth produced by the coffee activity, giving rise to an incipient process of industrialization and expansion of trade and the service sector.

Genetic studies have shown that Brazilians, whether classified as "brown", "white" or "black", usually have all three ancestries (European, African and indigenous), varying only in degree.

[46] In the Brazilian census, respondents must choose their color or race from 5 categories: Branca, Preta, Amarela, Parda or Indígena, which can be translated to White, Black, Yellow, Brown or Indigenous.

[56] The cities of São Paulo, Rio de Janeiro, Porto Alegre, Curitiba, Brasília and Belo Horizonte have the largest populations of Ashkenazi Jews.

[58][59] Northern Brazil, largely covered by the Amazon Rainforest, is mostly brown, due to a stronger Amerindian influence.

[60] The two remaining South Eastern states and Central-Western Brazil have a more balanced ratio among racial groups (around 50% White, 43% Pardo, 5% Black, 1% Yellow (East Asian)/Amerindian).

The populations in the North consisted of a significant proportion of Native American ancestry that was about two times higher than the African contribution.

In this work we analyzed the information content of 28 ancestry-informative SNPs into multiplexed panels using three parental population sources (African, Amerindian, and European) to infer the genetic admixture in an urban sample of the five Brazilian geopolitical regions.

[77] It is important to note that "the samples came from free of charge paternity test takers, thus as the researchers made it explicit: "the paternity tests were free of charge, the population samples involved people of variable socioeconomic strata, although likely to be leaning slightly towards the pardo group".

[77] An autosomal DNA study from 2009 found a similar profile "all the Brazilian samples (regions) lie more closely to the European group than to the African populations or to the Mestiços".

[82][83] A more recent study, from 2013, found the following composition in São Paulo state: 61.9% European, 25.5% African and 11.6% Native American.

Only autosomal DNA testing can reveal admixture structures, since it analyses millions of alleles from both maternal and paternal sides.

According to a genetic study in 2000 who analysed 247 samples (mainly identified as "white" in Brazil) who came from four of the five major geographic regions of the country, the mtDNA pool (maternal lineages) of present-day Brazilians clearly reflects the imprints of the early Portuguese colonization process (involving directional mating), as well as the recent immigrant waves (from Europe) of the last century.

A total of 22 haplogroups were detected in the whole Brazilian sample, revealing the three major continental origins of the current population, namely from America, Europe and Africa.

Portugal was estimated to be the main source of the male European lineages to Central-West, Southeast and South Brazil.

The sample from the Northern region presented the highest Native American ancestry (8.4%), whereas the more pronounced African contribution could be observed in the Northeastern population (15.1%).