The detection of germline mutations in BRCA1 and BRCA2 is essential to the formulation of clinical management strategies, and in Brazil, there is limited access to these services, mainly due to the costs/availability of genetic testing. Aiming at the identification of recurrent mutations that could be included in a low-cost mutation panel, used as a first screening approach, we compiled the testing reports of 649 probands with pathogenic/likely pathogenic variants referred to 28 public and private health care centers distributed across 11 Brazilian States. Overall, 126 and 103 distinct mutations were identified in BRCA1 and BRCA2, respectively. Twenty-six novel variants were reported from both genes, and BRCA2 showed higher mutational heterogeneity. Some recurrent mutations were reported exclusively in certain geographic regions, suggesting a founder effect. Our findings confirm that there is significant molecular heterogeneity in these genes among Brazilian carriers, while also suggesting that this heterogeneity precludes the use of screening protocols that include recurrent mutation testing only. This is the first study to show that profiles of recurrent mutations may be unique to different Brazilian regions. These data should be explored in larger regional cohorts to determine if screening with a panel of recurrent mutations would be effective.

There is general agreement that the Native American founder populations migrated from Asia into America through Beringia sometime during the Pleistocene, but the hypotheses concerning the ages and the number of these migrations and the size of the ancestral populations are surrounded by controversy. DNA sequence variations of several regions of the genome of Native Americans, especially in the mitochondrial DNA (mtDNA) control region, have been studied as a tool to help answer these questions. However, the small number of nucleotides studied and the nonclocklike rate of mtDNA control-region evolution impose several limitations to these results. Here we provide the sequence analysis of a continuous region of 8.8 kb of the mtDNA outside the D-loop for 40 individuals, 30 of whom are Native Americans whose mtDNA belongs to the four founder haplogroups. Haplogroups A, B, and C form monophyletic clades, but the five haplogroup D sequences have unstable positions and usually do not group together. The high degree of similarity in the nucleotide diversity and time of differentiation (i.e., approximately 21,000 years before present) of these four haplogroups support a common origin for these sequences and suggest that the populations who harbor them may also have a common history. Additional evidence supports the idea that this age of differentiation coincides with the process of colonization of the New World and supports the hypothesis of a single and early entry of the ancestral Asian population into the Americas.

Toxoplasma gondii is a cosmopolitan protozoan parasite of warm-blooded animals that causes high rates of infection in mammals and birds. Sparrows (Passer domesticus) are synantropic birds which are distributed worldwide. They serve as intermediate hosts for the parasite but are quite resistant to toxoplasmosis. The aims of this study were to determine the frequency of T. gondii infection in sparrows using serologic and molecular tests, and to investigate related parasites, such as Neospora caninum and Hammondia sp., using a nested PCR for Toxoplasmatinae DNA followed by sequence analysis of the PCR amplicons. A total of 293 sparrows were trapped at the states of Bahia and Pernambuco, Brazil. Tissues of 40 animals were available for molecular tests. Antibodies to T. gondii were found in 1.02% (3/293) of animals using a hemagglutination test, with titers ranging from 1:32 to 1:128. Toxoplasmatinae DNA was detected in 10/40 (25%) sparrows; after nucleotide sequencing, T. gondii was confirmed in 7/40 (17.5%) birds and N. caninum in 3/40 (7.5%) animals. Sparrows from Brazil were confirmed as intermediate hosts of T. gondii, that reinforces the potential importance of these birds on the transmission of the parasite to cats and other animals that may predate sparrows. In addition, N. caninum was detected for the first time in sparrows. To the authors' knowledge, this is the first wild synantropic bird species identified as intermediate host of N. caninum. These findings seem to have a great epidemiologic impact because of the cosmopolitan distribution of sparrows and due to their increasing population in urban and rural areas.

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