当前位置: 首页 > 期刊 > 《遗传学和分子生物学》 > 2006年第1期 > 正文
编号:11340756
Microsatellite studies on an isolated population of African descent in the Brazilian state of Bahia
http://www.100md.com 《遗传学和分子生物学》
     IUniversidade Estadual do Sudoeste da Bahia, Departamento de Ciências Biologicas, Jequie, BA, Brazil

    IIUniversidade de So Paulo, Faculdade de Medicina de Ribeiro Preto, Departamento de Genetica, Ribeiro Preto, SP, Brazil

    IIILaboratorio Frischmann Aisengart, Curitiba, PR, Brazil

    IVUniversidade Federal do Parana, Departamento de Genetica, Curitiba, PR, Brazil

    VUniversidade Estadual de Feira de Santana, Departamento de Ciências Biologicas, Feira de Santana, BA, Brazil

    ABSTRACT

    The African descent population of the Bananal community in the Brazilian state of Bahia (BA) was characterized as a genetic isolate and analyzed for some short tandem repeat (STR) microsatellite autosomic polymorphic loci (CSF1PO, TH01, TPOX, F13A1, FESFPS and vWA). These genetic variants were further compared to data obtained from an urban sample from the town of Jequie (BA) regarding demographic and anthropogenetic aspects. The Bananal sample comprised 32 unrelated individuals whereas Jequie was represented by 76 individuals. The Bananal Negroid Phenotypic Index (NPI) was 0.98 and the Negroid Cultural Index (NCI) 0.24. Consanguineous marriages occurred at a frequency of 34.61% and the F value was 0.0126. All six loci studied were in Hardy-Weinberg Equilibrium (p > 0.05). The genotypic and allele frequencies of the CSF1PO and vWA loci were similar. In the Bananal population the genic diversity of the THO1 locus was 66.8% and that of the F13A1 locus was 83.7%. The estimated ethnic racial admixture was 81% African and 19% Amerindian. The multiple correlation coefficient (R2) indicated adequate adaptation (99%). Total genetic variation for the six loci was 82.9% with an index of 6.7% for population subdivision (GST' = 0.067). Anthropologic data and results obtained from the allele frequencies of the loci studied are indicative of a genetic isolate in Bananal, reminiscent of the a 'quilombo community' (i.e. one founded by run away slaves).

    Key words: microsatellite, African-descendant isolate.

    Introduction

    This study was undertaken in the Bananal community located in the Rio de Contas district of the Chapada Diamantina region of the Brazilian state of Bahia, past studies having identified this community as a genetic isolate (Barbosa, 2003).

    Oral and historical information shows that the origin of the Bananal community is closely related to that of the Rio de Contas district (area 895 km2), a small community formed in the Seventeen Century due to the discovery of gold and diamonds in the Chapada Diamantina (literally, the plateau of diamonds) region of Bahia (Reis and Gomes, 1996). However, Messeder and Martins (1991) point out that public archives show that before the discovery of mineral resources this region was agricultural and there were communities of African slaves who had escaped from farms, such communities being known as quilombo communities (or simply quilombos) from the African word quilombo meaning 'a run away slave village'. The word Bananal is Portuguese, meaning a banana grove or plantation and thus indicates the agricultural origin of the community.

    Our work focused on the populational parameters and anthropogenetic aspects of the Bananal quilombo community in order to understand the processes that transformed this population into a genetic isolate. To recreate and understand the history of this group, we estimated the allele frequencies of selected short tandem repeat (STR) microsatellite autosomic polymorphic loci (CSF1PO, TPOX, TH01, F13A1, FES/FPS and vWA) and compared them to those observed in a population of African descent from the town of Jequie in the same region and those observed in other populations. We also estimated the ethnic admixture and genetic distances in the Bananal community and investigated the distribution of surnames and the past consanguinity of this group.

    Material and Methods

    Population

    The African descent Bananal community (13°36'00" S; 41°48'10" W) is located in a valley between Serra das Almas and Malhado at a distance of approximately 15 km from the city of Rio de Contas in the southern Chapada Diamantina region of the Brazilian state of Bahia.

    The Bananal community is composed of 26 small households, a church, and a district school. Houses are made of a clay (sometimes mixed with straw) and are built collectively by the members of the community. Electricity was partially installed in 1996 but is not present in all households. There is no water system or sewage facilities and the streets are unpaved. The population consist of 82 individuals (42 men and 40 women), according to data from 1995-1997.

    The town of Jequie in the same region has a population of 147,115 of mixed descent and is located at 13°51'50" S; 40°04'54" W.

    Population analysis

    Data from the families belonging to the Bananal community were obtained both from direct observation and interviews which took place in the households with the aid of a questionnaire which was applied to one of the adults (husband or wife) present. A pedigree of the Bananal community was reconstructed which considered the information obtained in the households as well as additional data obtained at the official registry office and at the parish level. The populational genetic parameters considered in this study were the reproductive population (Nr), effective population (Ne), effective migration (me), inbreeding coefficient (f), size of the isolate, and isolation index (i).

    Individuals belonging to the Bananal community were considered of African descent in accordance with the morphological 'racial' classification proposed by Krieger et al. (1965) and modified by Azevêdo (1975). Surnames were classified according to Tavares-Neto and Azevêdo (1977, 1978), names having a religious connotation being important cultural markers related to African ancestry in Northeastern Brazil (Barbosa et al., 1997).

    The Negroid Phenotypic Index (NPI) is obtained by counting all individuals classified as blacks and mulattos in relation to the total number of individuals that compose the sample, while the Negroid Cultural Index (NCI) takes into consideration the frequency of individuals who carry a surname with religious connotation, and the Amerindian Cultural Index (ACI) is given by the frequency of surnames referring to plants and animals (Azevêdo et al., 1982).

    Data on consanguineous marriages were obtained during the interviews and all of them were confirmed in the official registry documents. Such data were further confirmed by the surname analysis. There is no divergence between these three information.

    Laboratory analyses

    Venous blood samples were obtained from subjects after informed consent, the study previously having been approved by the ethical committees of the institutions involved. From each individual we collected 5 ml of venous blood in EDTA tubes and obtained high molecular weight DNA by the salting-out method (Miller et al., 1988) as modified by Alonso et al. (1997). We also used Chelex 100 (Walsh et al., 1991) for DNA extraction.

    We genotyped unrelated individuals of African descent, 68 from the Bananal community and 76 from Jequie, for the following human short tandem repeat (STR) microsatellite autosomic polymorphic loci and their alleles: the CSF1PO CSF-1 receptor gene c-fms proto-oncogene (Edwards et al. 199; Hammond et al. (1994); the TPOX thyroid peroxidase gene (Anker et al., 1992); the TH01 tyrosine hydroxylase gene (Polymeropoulos et al., 1991a); the vWA von Willebrand factor gene (Kimpton et al., 1992); the F13A1 coagulation factor XII subunit gene (Polymeropoulos et al., 1991b); and the FES/FPS c-fes/fps proto-oncogene (Polymeropoulos et al., 1991c).

    Polymerase chain reaction (PCR) DNA amplification was accomplished using the Gene Print kit (STR Systems, USA) and the FFv and CTT Multiplexes from Promega (USA) according to suggested protocols (Schumm et al., 1994). Amplified fragments were separated on denaturing polyacrylamide gel according to instructions from the manufacturer (Anon. 1999) and genotype was assigned after staining the gells with 6% (w/v) aqueous silver nitrate.

    Statistical analysis

    Allele and genotype frequencies were tested for the Hardy-Weinberg equilibrium by exact tests (Raymond and Rousset, 1995b) using version 3.2 of the GENEPOP program (Raymond and Rousset, 1995a). Intrapopulational (HS) and interpopulational (GST') Nei's genic diversity index were estimated using the program FSTAT (Goudet, 1999). Ethnic proportions were calculated by the genic identity method (Chakraborty, 1985) using the ADMIX 3 and ADMIX 2 programs. The allele frequencies representative of the African, European and Amerindian populations were the mean frequencies of other reports in the literature, adjusted by the sample size (Table 1). To calculate genetic distance, the ancestral African, European and Amerindian frequencies from the six loci studied were compared to those observed in our sample. The dendrogram was generated by the neighbor-joining method (Saitou and Nei, 1987) using the DISPAN program (Ota, 1993) and 1,000 bootstrap replicates.

    Results and Discussion

    For the Bananal sample 71.8% were phenotypic classified as black, and 28.2% were of mulattos phenotype consisting of 2.3% light-colored, 11.8% medium-colored and 14.1% dark-colored. There were no individuals classified as Amerindian or Caucasian by phenotype in this community. This date on phenotypic ethnic classification is based on facial morphological characteristics and skin color in body regions not exposed to the sun (Azevêdo, 1980).

    As regards anthropologic characteristics, the Bananal community NCI was 0.24, a median value compared to that expected for an African derived population (Azevêdo et al.,1982), possibly due to a founder effect related to the fact that few surnames with religious connotation were present in the initial composition of the community. The Bananal NPI was 0.8, higher than the 0.54-0.79 reported in other African derived populations (Azevêdo et al., 1982), possibly due to the fact that the Bananal community was isolated for for at least seven generations due to geographic, historical and social causes. The Bananal inbreeding coefficient (F) was 0.0126, higher than those reported in other Brazilian isolates (Magalhes and Arce-Gomes, 1987; Muniz, 1978; Freire-Maia and Cavalli, 1978) and probably due to the small size of the isolate favoring consanguineous marriages.

    The populational genetic parameters considered in this study were: reproductive population (Nr = 29), effective population (Ne = 14), effective migration (me = 19.2%), inbreeding coefficient (F = 0.0126), size of the isolate and isolation index (i = 2.688).

    The anthropologic and genetic data obtained represent important evidence that Bananal is reminiscent of a quilombo community. Information gathered in questionnaires as well as from the historical narrative of the oldest inhabitants are consistent with this and coherent with the documented historical facts (Viana-Filho, 1988; Alencastro, 2000; Tavares, 2001).

    The microsatellite frequencies found in the Bananal and Jequie communities were in Hardy-Weinberg Equilibrium and no new allele was detected (Table 1).

    The most frequent CSF1PO allele in Bananal was 12 (0.396) while 8 and 14 were rare (0.021 each) and 15 was not detected, the most frequent CSF1PO allele in the Jequie sample being 11 (0.333) and the least frequent 15 (0.008). Comparing our results with published data, we found that the frequency of the CSF1PO12 allele in Bananal was similar to the 0.301 reported for African-American populations (Budowle et al., 1997) and the 0.341 reported for populations from Mozambique (Alves et al., 2001). The CSF1PO10, 11 and 12 alleles were the most frequent CSF1PO alleles seen in the different populations (Table 1). The 11 CSF1PO allele is the most common (0.314) in Portuguese population (Santos et al. 1996). We also found that the same was true for African descents of Jequie for which the 11 frequency was (0.333). This data indicates that there was greater European gene flow into the African descent of Jequie population as compared to the African descent Bananal isolate.

    For the TH01 locus the most frequent allele was 7 (0.517) in the Bananal isolate. This allele was not polymorphic in African descendants from Jequie, in this sample the TH018 being was the most frequent (0.409) allele. In Africans and African-Americans TH017 was the most common, ranging from 0.262 to 0.434 (Budowle et al.,1997b; Dios et al., 1998; Alves et al., 2001).

    In relation to the TPOX locus the 11 allele (0.357) was the most frequent in Bananal, this allele also being common (0.342-0.360) in Africans (Dios et al. 1998; Alves et al. 2001). In individuals of African descent from Jequie, the most frequent allele was TPOX7 (0.326), this frequency being higher than that observed individuals of African, Portuguese and Amerindian descent and in other populations (www.uniduesseldorf.de/WWW/MedFak/Serology/database.html).

    For the F13A1 locus, the 5 allele was the most frequent in the Bananal (0.333) and Jequie (0.270) samples, this allele also being common in African-Americans (0.342) and Africans (0.337 to 0.500; Destro-Bisol et al., 2000).

    In the case of the FES/FPS locus the most frequent allele in Bananal was 12 (0.345), the frequency of this allele being higher in this population than in Africans, Portuguese or Amerindians (Table 1), probably due to genetic drift. The second most common allele in Bananal (11; 0.255) was the most frequent FES/FPS allele in Jequie (0.362), African-Americans (0.355) and Africans (0.359 to 0.414; Destro-Bisol et al., 2000).

    For the vWA locus, 16 (0.346) was the most frequent allele in Bananal, whereas in Jequie the 15 and 17 alleles occurred at the same frequency (0.250), and the allele 16 being (0.222) the second most frequent. When compared to other populations, it was found that 16 is the most frequent vWA allele in Africans and African-Americans (0.261 to 0.371; Destro-Bisol et al., 2000). In the African descendant population of So Gonalo, Bahia (Sousa, 2001) the allele 16 was also the most frequent (0.286). For the Portuguese populations described by Santos et al. (1996) and Gusmo et al. (1997), allele 17 (0.255) and allele 16 (0.219) were also the most frequent vWA alleles, similar findings having been reported in the admixed Brazilian population described by Grattapaglia et al. (2001).

    Of the six loci studied in individuals of African descent from Bananal and Jequie, four (TH01, TPOX, FES/FPS and vWA) presented heterogeneous frequencies between these two populations. In the Bananal population, genic diversity, measured as expected heterozygosity, for these six loci varied from 66.8% for the TH01 locus to 83.7% for the F13A1 locus, while in the Jequie population the values were of 72.8% for the TH01 locus and 82.8% for F13A1 (Table 2). The mean value for genic diversity was found to be very close for both populations (0.771 for Bananal and 0.776 for Jequie). After analyzing each locus individually, we concluded that for TH01 and TPOX, values were higher in Jequie than in Bananal but for the other loci the opposite was true. We expected higher values in Jequie because this population was more exposed to genetic influx and migration. The greater genic diversity in Bananal, a characteristic also observed in African populations, can be attributed to the historical fact that Bananal was founded by individuals of African descendant.

    Total genic diversity for all six loci was in the order of 82.9% (Table 3). The heterozygosity index represents the frequency of heterozygotes for each locus in the population and can be related to the both the effective size of the population and to its degree of isolation (Bosch et al., 2001). These results are in accordance with those obtained for other African populations.

    We found intrapopulational genetic diversity to be high and similar to that found in populations of African ascendant from different regions of the African continent. Our data also reveals that Bananal was formed by individuals coming from different ethnic groups of African origin, high genetic diversity being in accordance with historical facts from Bahia and Brazil in general which indicate that the traffic in African slaves involved trafficking individuals with diverse ethnic origins (Tavares, 2001).

    A value of 6.7% (Table 3) for populational subdivision (GST' = 0.067) is indicative of group heterogeneity, reflecting the multifaceted African origin of Bananal and its historical isolation, this situation being different from that seen in the open population of Jequie which is composed of diverse ethnic groups such as Europeans, Amerindians, Arabs and Africans.

    The mean frequencies found for each locus in the ancestral populations (Table 1) were used to estimate the ethnic admixture by the genic identity method, initially using a trihybrid model for both the Jequie and Bananal samples. Using this model the African-derived Jequie urban population was shown to consist of 41.5% African, 35.8% European and 22.6% Amerindian ancestry with a multiple correlation coefficient (R2) of 82.3%. However, for the Bananal data the trihybrid model was inconsistent but when a dihybrid model was applied considering the frequencies for both African and Amerindian ancestral populations the African contribution to the Bananal population was calculated to be in the order of 81% and the Amerindian contribution 19%, the multiple correlation coefficient (R2) indicated a good fit (99%) to this model. This date is different from the phenotypic ethnic classification where no Amerindian phenotype was detected suggesting that the short tandem repeat (STR) microsatellite autosomic polymorphic loci studied herein are a more powerful tool on discriminating ethnic admixture. Gene flow and/or genetic drift may explain the Amerindian contribution to the Bananal community gene pool.

    The high contribution of Africans to the gene pool of our African descent sample of Jequie differs from that seen in previous studies of northeastern Brazilian populations (Callegari-Jacques et al 2003; Ferreira et al. 2005), possibly due to the careful choice of African-descendants by the morphological ethnic classification (Azevêdo, 1980) used in our study.

    Our results indicate that both the Jequie and Bananal populations were of African descent with the long isolation of the Bananal population explaining the differences found between them while the similarities resulted from the fact that their shared origin was both African and Amerindian, although the Jequie population showed a greater degree of ethnic admixture in that it also contained a European contribution.

    Regarding any European contribution to the Bananal population, further studies using other autosomic microsatellite markers along with Y chromosome and mitochondrial markers would greatly contribute to our understanding of the contribution of Europeans to this community.

    Nei's genetic distance was used to compare the ancestral and actual populations in relation to the loci studied and generate the neighbor-joining dendrogram shown in Figure 1 which shows a strong African component in both the Bananal and Jequie populations.

    It is important to emphasize that our genic frequencies, NPI, NCI and populational data support the historical facts and information related to the populations studied and to the formation of Brazil as a nation. Our data also support the historical accounts that show that the Bananal community persisted as a genetic isolate reminiscent of the original quilombo communities.

    Acknowledgments

    We thank the inhabitants of Bananal who eagerly participated in this study, especially Lourdinha for her warm reception and help and explanation concerning the data collected. We also thank the inhabitants of Jequie for their participation in the control sample. The financial support of the Universidade Estadual do Sudoeste da Bahia, Fundao de Amparo a Pesquisa do Estado da Bahia (FAPESB), and the Brazilian National Research Council for Scientific and Technologic Development (CNPq) is also gratefully acknowledged.

    References

    Anon (1999) Tecnical Manual: Gene PrintRSTR Systems Silver Stain Detection. Promega, USA, 52 pp.

    Alencastro LF (2000) Trato dos Viventes: Formao do Brasil no Atlantico Sul. Editora Companhia das Letras, So Paulo, 525 pp.

    Alonso CAM, Malaghini M, Pereira NF, Ribeiro EMSF and Pasquini R (1997) Avaliao do quimerismo apos o transplante de medula ossea (TMO) atraves da utilizao de sistemas "triplex" de marcadores VNTR. Braz J Genetics 20:219.

    Amorim A, Gusmao L and Prata MJ (1996) Population and formal genetics of the STRs TPO, TH01 and VWFA31/A in North Portugal. Adv Forens Haemogenet 6:486-488.

    Anjos MJ, Carvalho M, Andrade L, Corte-Real F, Vieira DN and Vide MC (2000) Allele frequencies of STR multiplex systems in two Portuguese population samples. Progr Forensic Genet 8:208-211.

    Anker R, Steinbrueck T and Donis-Keller H (1992) Tetranucleotide repeat polymorphism at the human thyroid peroxidase (hTPO) locus. Hum Mol Genet 1:137.

    Asmundo A and Crinò C (1998) Population study of the short tandem repeat polymorphisms HumTH01, HumvWA31, HumFESFPS and HumF13A01 in Sicily (Southern Italy). Int J Legal Med 111:281-283.

    Alves C, Gusmo and Amorim A (2001) STR data (ampflstr profiler Plus and GenePrint CTTv) from Mozambique. Forensic Sci Int 119:131-133.

    Azevêdo ES (1975) O sistema genetico das desidrogenases alcoolicas em mestios da Bahia e em brancos europeus. PhD Thesis, Universidade Federal da Bahia, Salvador.

    Azevêdo ES (1980) Subgroup studies of black admixture within a mixed population of Bahia, Brazil. Curr Anthrop 21:360-363.

    Azevêdo ES, Fortuna CMM, Silva KMC, Sousa MGF, Machado MA, Lima AVMD, Aguiar ME, Abe K, Eulalio MCMN, Conceio MM, Silva MCBO and Santos MG (1982) Spread and diversity of human populations in Bahia, Brazil. Hum Biol 54:329-341.

    Azevêdo ES, Costa TP, Silva MCBO and Ribeiro LR (1983) The use of surnames for interpreting gene frequency distribution and past racial admixture. Hum Biol 55:235-242.

    Barbosa AAL, Cavalli IJ, Abe K, Santos MG and Azevêdo ES (1997) Family names and the length of the Y chromosome in Brazilian blacks. Braz J Genetics 20:93-96.

    Barbosa AAL (2003) Analise de microssatelites do Isolado Bananal (BA) - Parametros populacionais. PhD Thesis, Universidade Federal do Parana, Curitiba.

    Bosch E, Clarimon J, Perez-Lezaun A and Cafafell F (2001) STR data for 21 loci in northwestern Africa. Forensic Sci Int 116:41-51.

    Brinkmann B, Junge A, Meyer E Azevêdo and Wiegand P (1998) Population genetic diversity in relation to microsatellite heterogeneity. Hum Mut 11:135-144.

    Brinkmann B, Sajantila A, Goedde HW, Matsumoto H, Nishi K and Wiegand P (1996) Population genetic comparisons among eight populations using allele frequency and sequence data from three microsatellite loci. Eur J Hum Genet 4:175-182.

    Budowle B, Nhari IT, Moretti TR, Kanoyangwa SB,Masuka E, Defenbaugh DA and Smerick JB (1997a) Zimbabwe Black population data on the six short tandem repeat loci - CSF1PO, TPOX, THO1, D3S1358, vWA and FGA. Forensic Sci Int 90:215-221.

    Budowle B, Smerick JB, Keys KM and Moretti TR (1997b) United States population data on the multiplex short tandem repeat loci - HUMTHO1, TPOX, and CSF1PO - And the variable number tandem repeat locus D1S80. J Forensic Sci 42:846-849.

    Callegari-Jacques SM, Grattapaglia D, Salzano FM, Salamoni SP, Crossetti SG, Ferreira ME and Hutz MH (2003) Historical genetics: Spatiotemporal analysis of the formation of the Brazilian population. Am J Hum Biol15:824-34.

    Chakraborty R (1985) Gene identity in racial hybrids and estimation of admixture rates. In: Neel JV and Ahuja Y (eds) Genetic Microdifferentiation in Man and Other Animals. Indian Anthropological Association, Delhi University, Delhi, pp 171-180.

    Corte-Real F, Andrade L, Carvalho M, Anjos MJ, Gamero J, Vieira DN, Carracedo A and Vide MC (2000) Comparative analysis of STR data for Portuguese spoken countries. Progr Forensic Genet 8:212-214.

    Deka R, Shriver MD, Yu LM, Mueller Heidreich E, Jin L, Zhong Y, McGarvey ST, Swarup Agarwal S, Bunker CH, Miki T, Hundrieser J, Yin SJ, Raskin S, Barrantes R, Ferrell RE and Chakraborty R (1999) Genetic variation at twenty-three microsatellite loci in sixteen human populations. J Genet 78:99-121

    Destro-Bisol G, Boschi I, Caglia A, Tofanelli S, Pascali V, Paoli G and Spedini G (2000) Microsatellite variation in Central Africa: An analysis of intrapopulational and interpopulational genetic diversity. Am J Phys Anthrop 112:319-337.

    Dios S, Luis JR, Teixeira-Ribeiro JC and Caeiro B (1998) Population database of STRs in West Africa: A genetic study of TPOX, HUMvWA31, HUMTH01, and CYP19. Genetica 104:77-83.

    Edwards A, Cititello A, Hammond HA and Caskey CT (1991) DNA typing and genetic mapping with trimeric and tetrameric tandem repeats. Am J Hum Genet 49:746-756.

    Espinheira R, Viriato L, Silva C, Ribeiro T, Brito M, Pinto-Ribeiro I and Geada H (2000) African population genetic data with AmpF1STR Profiler Plus&trade. Progr Forensic Genet 8:230-232.

    Ferreira FL, Leal-Mesquita ER, Santos SEB and Ribeiro-dos-Santos AKC (2005) Genetic caracterization of the population of So Luis, MA, Brazil. Genet Mol Biol 28:22-31.

    Freire-Maia N and Cavalli IJ (1978) Genetic investigations in a northern Brazilian island: Population structure. Hum Hered 28:380-385.

    Gene M, Moreno P, Borrego N, Pique E, Xifro A, Fuentes M, Bert F, Corella A, Perez-Perez A, Turbon D, Corbella J and Huguet E (2000) Population study of Aymara Amerindians for the PCR-DNA polymorphisms HUMTH01, HUMVWA31A, D3S1358, D8S1179, D18S51, D19S253, YNZ22 and HLA-DQalpha. Int J Legal Med 113:126-8.

    Goudet J (1999) A program to estimate and test gene diversities and fixation indices FSTAT (version 2.8). Updated from Goudet, 1995.Grattapaglia D, Schmidt AB, Costa e Silva C, Stringher C, Fernandes AP and Ferreira ME (2001) Brazilian population database for the 13 STR loci of the AmpF/STR Profiler PlusTM and CofilerTM multiplex kits. Forensic Sci Int 118:91-94.

    Gusmo L, Prata MJ, Amorim A, Silva F and Bessa I (1997) Characterization of four short tandem repeat loci (TH01, vWA31/A, CD4, and TP53) in Portugal. Hum Biol 69:31-40.

    Hammond HA, Jin l, Zhong Y, Caskey CT and Chakraborty R (1994) Evaluation of 13 short tandem repeat loci for use in personal identification applications. Am J Hum Genet 55:175-189.

    Huguet E, Borrego N, Pinheiro MF, Luna M, Corbella J, Mas J, Gene M and Moreno P (1998) Annobon Island population (Equatorial Guinea) characterized by five VNTRs-PCR polymorphisms. Progr Forensic Genet 7:329-331.

    Kimpton CP, Walton A and Gill P (1992) A further tetranucleotide repeat polymorphism in the vWA gene. Hum Mol Genet 1:287.

    Krieger H, Morton NE, Mi MP, Azevêdo ES, Freire-Maia A and Yasuda N (1965) Racial admixture in northeastern Brazil. Ann Hum Genet 29:113-125.

    Lurdes-Pontes M, Pinheiro MF, Huguet E, Gene M and Pinto da Costa J (1998) Automated typing of 4 tetrameric STR: A North of Portugal database. Progr Forensic Genet 7:335-337.

    Magalhes JCM and Arce-Gomez B (1987) Study on a Brazilian isolate: Population struture and random genetic drift. Hum Hered 37:278-284.

    Mendes-Junior CT (2001) Freqvências alelicas de polimorfismos de DNA do tipo STR em indigenas da Amaznia brasileira. Master Thesis, Universidade de So Paulo, Ribeiro Preto.

    Messender MLL and Martins MAM (1991) Arraiais de Rio de Contas: Uma comunidade de cor. Caderno CRH, suplemento:36-49.

    Miller SA, Dyres DD and Polesky HF (1988) A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Res 16:1215-1218.

    Miranda C, Prata MJ and Amorim A (1998) Population genetics of the F13A1 STR polymorphism in North Portugal and S. Tome e Principe. Progr Forensic Genet 7:338-340.

    Muniz MD (1978) Estudos demograficos e geneticos em uma comunidade de origem polonesa. Master Thesis, Universidade Federal do Parana, Curitiba.

    Nei M (1987) Molecular Evolutionary Genetics. Columbia University Press, New York, 512 pp.

    Oliveira SF, Pedrosa MAF, Sousa SMB, Mingroni-Netto RC, Abe-Sandes K, Ferrari I, Barbosa AAL, Auricchio MT and Klautau-Guimares MN (2002) Heterogeneous distribution of HbS and HbC alleles in Afro-derived Brazilian populations. Int J Hum Genet 2:153-160.

    Ota T (1993) Program DISPAN: Genetic Distance and Phylogenetic Analysis [http://iubio.bio.indiana.edu:7780/archive/ 00000022/]. Copyright of University Park, Institute of Molecular Evolutinary Genetics, Pennsylvania State University, University Park, PA.

    Pereira L, Gusmo L, Amorim A, Prata MJ, Silva F, Bessa I and Santos MT (1996) Population and segregation data on the STRs CD4, FES/FPS, MBP (Locus B), TH01, TP53, TPO and vWA31/A in North Portugal. Proc. 7th Int. Symp. Human Idenfication, Promega Corp, pp 193. Perez-Lezaun A, Calafell F, Mateu E, Comas D, Bosch E and Bertranpetit J (1997) Allele frequencies for 20 microsatellites in a worldwide population survey. Hum Hered 47:189-196.

    Perez-Lezaun A, Calafell F, Clarimon J, Bosch E, Mateu E, Gusmo L, Amorim A, Benchemsi N and Bertranpetit J (2000) Allele frequencies of 13 short tandem repeats in population samples from the Iberian Peninsula and Northern Africa. Int J Legal Med 113:208-214.

    Pinheiro F, Pontes L, da Costa JP, Huguet E, Moreno P and Gene M (2000) Allelic distribution of four tetranucleotide repeat loci (D3S1358, D18S51, D19S253, and FGA) in a population from Porto (North Portugal). J Forensic Sci 45:891-2.

    Polymeropoulos MH, Rath DS, Xiao H and Merril CR (1991a) Tetranucleotide repeat polymorphism at the human tyrosine hidroxylase gene (TH). Nucleic Acids Res 19:3753.

    Polymeropoulos MH, Rath DS, Xiao H and Merril CR(1991b) Tetranucleotide repeat polymorphism at the human coagulation factor XIII. A subunit gene (F13A01). Nucleic Acids Res 19:4306.

    Polymeropoulos MH, Rath DS, Xiao H and Merril CR (1991c) Tetranucleotide repeat polymorphism at the human c-fes/fps proto-oncogene (FES). Nucleic Acids Res 19:4018.

    Raymond M and Rousset F (1995a) Genepop (version 1.2, 3.2): Population genetics software for exact test and ecumenism. J Hered 86:248-249.

    Raymond M and Rousset F (1995b) An exact test for population differentiation. Evolution 49:1280-1283.

    Reis JJ and Gomes FS (1996) Liberdade por um Fio: Historia dos Quilombos no Brasil. Companhia das Letras, So Paulo, 512 pp.

    Saitou W and Nei M (1987) The neighbour-joining method: A new method for re constructing phylogenetic trees. Mol Bio Evol 4:406-425.

    Santos SMM, Budowle B, Smerick JB, Keys KM and Moretti TR (1996) Portuguese population data on the six short tandem repeat loci - CSF1PO, TPOX, THO1, D3S1358, vWA and FGA. Forensic Sci Int 83:229-235.

    Schumm JW, Lins A, Puers C and Sprecher C (1993) Development of nonisotopic multiplex amplification sets for analysis of polymorphic STR loci. Proceedings from the Fourth International Symposium on Human Identification 1993, Promega Corporation, pp 177-187.

    Sousa SMB (2001). Estrutura genetica de uma comunidade afro-brasileira, So Gonalo (BA). Master Thesis, Universidade de So Paulo, Ribeiro Preto.

    Souto L, Amorim A and Vide MC (1998) Population and segregation data on the multiplex system (TH01, VWA, FES, F13A1) from Central Portugal. Progr Forensic Genet 7:363-365.

    Tavares LHD (2001) Historia da Bahia.10a edio. Editora UNESP/EDUFBA, So Paulo/Salvador, 542 pp.

    Tavares-Neto J and Azevêdo ES (1977) Racial origin and historical aspects of family names in Bahia, Brazil. Hum Biol 49:287-299.

    Tavares-Neto J and Azevêdo ES (1978) Family name and ABO blood group frequencies in a mixed population of Bahia, Brazil. Hum Biol 50:361-367.

    Yunis JJ, Garcia O, Uriarte I and Yunis EJ (2000) Population data on 6 short tandem repeat loci in a sample of Caucasian-Mestizos from Colombia. Int J Legal Med 113:175-178.

    Walsh PS, Metzger DA and Higuchi R (1991) ChelexR 100 as a medium for simple extraction of DNA for PCR-based typing from forensic material. Bio. Techniques 10:506.

    Wanderley-Santos LM (2001) STRs autossmicos e ligados ao cromossomo Y em indigenas brasileiros. PhD Thesis, Universidade de So Paulo, Ribeiro Preto.

    Viana-Filho L (1988) O Negro na Bahia. 3a edio. Editora Nova Fronteira, Rio de Janeiro, 245 pp.(Ana Angelica Leal Barbosa)