Background/Objectives: In Brazil, quilombos—African-descendant resistance communities—emerged during slavery and persisted beyond its abolition. The state of Paraná, in Southern Brazil, is home to 86 quilombos, yet their genetic diversity remains entirely unexplored, and little is known about their subcontinental African origins. Methods: To explore the demographic history of these communities and the reach of the Transatlantic Slave Trade in Southern Brazil, we analyzed Y and mitochondrial DNA haplotypes in samples from two quilombo communities from Paraná, Feixo (n = 117) and Restinga (n = 47). Results: Our findings reveal a significant African maternal ancestry in both communities, with Feixo exhibiting 35% and Restinga showing a striking 78.72% of maternal haplogroups of African origin. Feixo’s mtDNA haplotypes display affinities with Bantu-speaking populations from Central-Western and Southeastern Africa (such as Angola, Congo, and Mozambique), whereas those found in Restinga are more closely aligned with lineages frequent in Western Africa. Y-chromosome data reveal 39.4% and 25% African paternal ancestry in Feixo and Restinga, respectively, with most African chromosomes assigned to haplogroup E1b1b1-M35, which has a broad frequency across eastern Africa. Conclusions: These results offer novel insights into the history of the African diaspora in a previously unstudied Brazilian region, suggesting African sources—including underdocumented Eastern/Southern lineages—and contributing useful new clues to their broader within-Africa affinities.

The Mennonite population has a unique history of 500 years of genetic isolation shaped by at least three demographic bottlenecks, founder effects, inbreeding, epidemics, and migrations. To evaluate their susceptibility for monogenic diseases (MD), we performed whole‐exome sequencing on 325 volunteers from two South Brazilian Mennonite settlements (one urban and another rural). We identified 23 pathogenic variants (P) and 27 likely P, with 22.8% accounting for endocrine, nutritional, and metabolic MDs, 17.5% for developmental anomalies, and 10.5% for nervous system MDs. HFE rs1800562 causing hereditary hemochromatosis presented the highest frequency (7.54%), followed by BTD rs13078881 for biotinidase deficiency (7.08%), FLG rs61816761 for ichthyosis vulgaris and atopic dermatitis (3.38%), and FANCM rs147021911 for Fanconi anemia (3.08%). Genomic and genealogical analysis confirmed their European origin, with very low consanguinity and high heterozygosity coefficients, confirming a random selection of refugees that emigrated from widespread settlements in Russia to Brazil in 1930. There was also a slight deviation to Native Americans for self‐reported admixed Mennonites. Even so, founder effects occurred for 96% of P, whose frequencies differed from non‐Finnish Europeans, Amish, and Brazilian populations. These findings highlight the genetic risks in this population, reinforcing the importance of genetic counseling, screening programs, and Personalized and Preventive Medicine strategies to mitigate health risks associated with inherited conditions.