Third molar agenesis in a trihybrid Brazilian population

The frequency of missing third molars is about eight per cent per quadrant in a sample of 490 males of the mixed White/Negro/Indian population of Natal, Brazil. Absence of the four third molars appears in two per cent of the individuals of the sample. The degree of asymmetry for the trait was not marked. No differences were observed when the persons were separated on morphological grounds as Whites or Negroids suggesting that these segregants may be genetically homogeneous in relation to this and other characteristics.     

Two new Bf S subtypes revealed by isoelectric focusing and immunofixation

Summary The genetic types of the properdin factor B were analyzed by isoelectric focusing on polyacrylamide gels and subsequent immunofixation. Sera from 516 unrelated, healthy individuals from Southern Germany were examined. Two new subtypes of the Bf*S allele were observed. They were provisionally named Bf*Sb1 and Bf*Sb2 (b = basic), since the position of their bands is located slightly towards the cathode. Whereas Bf Sb2 has, thus far, been found only in a single individual, Bf Sb1 was found in five unrelated persons and in a mother and her child indicating a simple codominant mode of inheritance. The combined frequency of the Bf*Sb alleles was calculated to be 0.0067.     

No evidence for linkage disequilibrium between Bf and GLO in African Negroids

Summary A sample of South African Negroids (n=791) was scored for each individual's Bf and GLO phenotype. (The genes for the Bf and GLO polymorphisms are included in a known cluster of linked genes on chromosome 6.) Following a ²-test the respective two series of alleles were found to be distributed at random, i.e., there was no evidence for a linkage disequilibrium. This result is discussed in terms of the linkage relationships and map distances of the genetic markers involved.Supported by the Deutsche Forschungsgemeinschaft (DFG), Bonn-Bad GodesbergSupported by a grant from the Georg and Agnes Blumenthal-Stiftung, BerlinSupported by a research fellowship (1975/76) awarded by the Alexander von Humboldt-Stiftung, Bonn-Bad Godesberg     

Race differences in the sex dimorphism of dermatoglyphic traits

For three dermatoglyphic traits it could be proved that there are racial differences in sex dimorphism. The results are as follow: (1) For the index of pattern intensity (158 samples), the sex difference is significantly higher in Negroids than in Europoids and Mongoloids. (2) For total ridge count, the sex difference is lower in Negroids than in Europoids. The discrepancy between (1) and (2) has been discussed. (3) The number of samples with higher frequencies of palmar patterns in males than in females is significantly higher in Negroids than in Mongoloids and Europoids for the hypothenar and III interdigital and lower in Mongoloids than in Europoids and Negroids for the II interdigital (max. 127 samples).     

An intragenic deletion of the P gene is the common mutation causing tyrosinase-positive oculocutaneous albinism in southern African Negroids.

Tyrosinase-positive oculocutaneous albinism (OCA2), an autosomal recessive disorder of the melanin biosynthetic pathway, is the most common recessive disorder occurring in southern African Bantu-speaking Negroids, with an overall prevalence of 1/3,900. The OCA2 gene, P, has been mapped to chromosome 15q11-q13, and recently alterations in the P gene have been identified in OCA2 individuals. An intragenic deletion has been described and proposed to be of African origin because of its occurrence in four unrelated African American OCA2 individuals and in two individuals, one from Zaire and the other from Cameroon. This study shows that the intragenic deletion is a common cause of OCA2 in southern African Negroids (114/146 [.78]; OCA2 chromosomes) and is associated with one common haplotype (43/55 [.78]; OCA2 chromosomes), confirming the African origin of this allele. On the basis of haplotype data, it would appear that at least seven additional, less frequent OCA2 mutations occur in this population.     

Human MHC class III genes, Bf and C4. Polymorphism, complotypes and association with MHC class I genes in the Finnish population

Electrophoretically detected genetic polymorphism of human MHC class III genes, factor B (Bf) and complement C4A and C4B, was studied in the Finnish population. Bf alleles were determined in a panel of sera from 70 unrelated individuals. The common Bf alleles, Bf*S and Bf*F, had frequencies of 73% and 26%, respectively. Only in 1 individual was another allele, Bf*F1, detected. The frequencies of the C4A and C4B alleles were based on studies of 254 unrelated individuals. In this panel, five different alleles were detected at the C4A locus and four at the C4B locus. At both loci an allele without a gene product, i.e. a 'null' allele, was observed with high frequency, 11% for C4A 'null' and 17% for C4B 'null'. The association of complotypes to HLA haplotypes was analyzed in 70 chromosomes. The most common combination, defined by class I and class III alleles, was HLA-B7-S31 (13%), followed by HLA-B35-F20 (8.4%) and HLA-B8-S03 (7.1%). Some HLA-B specificities, for example B15, B27 and B40, were associated with a variety of complotypes. The importance of complotyping in HLA genetics is discussed.     

Frequency distribution of XbaIG > T and HaeIIIT > C <Emphasis Type="Italic">GLUT1</Emphasis> polymorphisms among different Brazilian ethnic groups

GLUT is the major glucose transporter in mammalian cells. Single nucleotide polymorphisms (SNP) at GLUT1 promoter and regulatory regions have been associated to the risk of developing nephropathy in different type 1 and type 2 diabetic populations. It has been demonstrated that differences in allelic and genotypic frequencies of GLUT1 gene (SLC2A1) polymorphisms occur among different populations. Therefore, ethnic differences in distribution of GLUT1 gene polymorphisms may be an important factor in determining gene-disease association. In this study, we investigated the XbaIG > T and HaeIIIT > C polymorphisms in six different Brazilian populations: 102 individuals from Salvador population (Northern Brazil), 56 European descendants from Joinville (South Brazil), 85 Indians from Tiryió tribe (North Brazil) and 127 samples from Southern Brazil: 44 from European descendants, 42 from African descendants and 41 from Japanese descendants. Genotype frequencies from both sites did not differ significantly from those expected under the Hardy–Weinberg equilibrium. We verified that the allele frequencies of both polymorphisms were heterogeneous in these six Brazilian ethnic groups.     

An integrative multidisciplinary approach to understanding cryptic divergence in Brazilian species of the Anastrepha fraterculus complex (Diptera: Tephritidae)

An integrative multidisciplinary approach was used to delimit boundaries among cryptic species within the Anastrepha fraterculus complex in Brazil. Sexual compatibility, courtship and sexual acoustic behaviour, female morphometric variability, variation for the mitochondrial gene COI, and the presence of Wolbachia were compared among A. fraterculus populations from the Southern (Vacaria, Pelotas, Bento Gonçalves, São Joaquim) and Southeastern (Piracicaba) regions of Brazil. Our results suggest full mating compatibility among A. fraterculus populations from the Southern region and partial pre‐zygotic reproductive isolation of these populations when compared with the population from the Southeastern region. A. fraterculus populations from both regions differed in the frequency of courtship displays and aspects of the calling phase and mounting acoustic signal. Morphometric analysis showed differences between Southern region and Southeastern region samples. All populations analyzed were infected with Wolbachia. The trees generated from the COI sequencing data are broadly congruent with the behavioural and morphometric data with the exception of one Southern population. The likely mechanisms by which A. fraterculus populations might have diverged are discussed in detail based on behavioural, morphometric, molecular genetics, and biogeographical studies.     

Frequencies of atypical serum cholinesterase among Caucasians and Negroes from southern Brazil

Frequencies of the CHE1*A allele were estimated on the basis of a sample of 999 Caucasians (1.5%) and 1,015 Negroids (0.84%) from Curitiba, Brazil. The frequency found in the Negroid subsample allows an estimate of 50 +/- 15% of Caucasoid admixture and an average gene flow in the white-black direction of the order of 5.6% per generation.     

Low frequency of the deltaAF508 mutation of the CFTR gene in a highly admixed population in Bahia, Brazil

Cystic fibrosis (CF) is the most common autosomal recessive disease in the European (Caucasian) population, with an incidence of 1:2000 to 1:8000. The deltaF508 mutation (66%) is predominant among more than 1300 different mutations of the CFTR gene. The population of the state of Bahia, in northeastern Brazil, is highly admixed (mainly African and Portuguese descendants), and so far, no study has been carried out to assess the molecular basis of CF in this population. We determined the deltaF508 mutation frequency in 503 individuals from the general population of Salvador, the capital of the state of Bahia, and in 144 CF patients from several cities in Bahia. In the general population samples we found 4 individuals heterozygous for the deltaF508 mutation (allele frequency of 0.4%). This frequency was lower than that found in the state of Rio de Janeiro, in southeastern Brazil, and similar to that reported for the state of Paraná, in the far south. In the CF patients we found 9 heterozygous individuals and 8 homozygous individuals (allele frequency of 8.68%) for the deltaF508 mutation. This frequency is considerably lower than the average frequency of CF in the world population and in the Brazilian CF population of European ancestry (47%). These data could be explained by the intense admixture among the population in Bahia, and they suggest a heterogeneous molecular basis for CF in this area of Brazil.     

Genetic polymorphisms of C3 and Bf in the Chinese population

The distribution of C3 and Bf in a Chinese population sample has been investigated. In a total of 388 individuals, 385 SS and 3 FS C3 phenotypes were observed and the following gene frequencies calculated: C3F = 0.0039, C3S = 0.9961. In 200 unrelated individuals, 155 S, 38 FS, 6 F and 1 FS 0.7 Bf phenotypes were found. The gene frequencies calculated from these were BfS = 0.8700, BfF = 0.1275, BfS0.7 = 0.0025.     

Gm and Inv allotypes in a Gypsy sample.

Serum samples from 226 Gypsies were tested for Gm(1,2,4,5,8,10,11,14,17,21,23,25) and for Inv(1,2). The Gm phenotypes found are very numerous and the more frequent among this population are: Gm(4,5, 8,10,11,14,17,23,25) and Gm(1,2,4,5,8,10,11,14,17,21,23,25). All the phenotypes except three can be explained by nine haplotypes: Gm4,5,8,10,11,14,23,25, Gm1,4,5,8,10,11,14,23,25, Gm4,5,8,10,11,14,25, Gm1,17,21, Gm1,10,11,17,25, Gm1,2,17,21, Gm1,8,17,21, Gm1,8,17,21,23 and Gm1,5,10,11,14,17. The haplotypes Gm1,17,21, Gm1,2,17,21, Gm4,5,8,10,11,14,25 (with or without Gm[ 3]) are all three common among Caucasoids, Gm1,4,5,10,11,14,23,25 (common among Mongoloids) and Gm1,5,10,11,14,17 (common to Negroids). For the Inv system, this population possesses a very low frequency of Inv(1) and Inv(2).     

Human chromosomal polymorphism. V. Chromosomal Q polymorphism in African populations

Summary The distribution pattern of Q-heterochromatin variants in seven autosomes (3, 4, 13–15, 21, and 22) was studied in three aboriginal Negroid populations of Africa (Mozambique, Angola, and Ethiopia). It was shown that among African Negroids there are no individuals completely lacking Q-heterochromatin bands with fluorescence levels 4 and 5. The mean number of Q variants per individual was 3.47, 4.80, and 4.85 in the Ethiopian, Mozambique, and Angola populations, respectively. The observed homo- and heteromorphic frequencies always agreed with those predicted by the law of Hardy-Weinberg. The populations of tropical lowland Negroids (Mozambique and Angola) proved to be significantly homogeneous both in the frequency of Q variants and the mean number of these variants per individual, so they were examined as a single group. However, comparative analysis of highland (Ethiopians) and lowland Negroids revealed statistically significant differences. The following questions are discussed: (1) the possible selective value of chromosomal Q heterochromatin material in the adaptation of human populations to high-altitude climate; (2) the possible existence of intraracial heterogeneity in Negroids living in different ecological zones of Africa; (3) the possible taxonomic value of an inverted Q-heterochromatin band in chromosome 3 in ethnic anthropology.     

Studies on four restriction fragment length polymorphisms of the type I collagen genes in two Italian populations

Type I collagen, the most abundant of the collagen protein family, is encoded by two genes, COL1A1 and COL1A2. Two random population samples, one from central Italy and one from southern Italy, were studied for 1 restriction fragment length polymorphism (RFLP) of COL1A1 (RsaI) and 3 RFLPs of COL1A2 (EcoRI, RsaI and MspI). A considerable heterogeneity for COL1A1/RsaI was found not only between Italians and English but even among Italians. The potential usefulness of these RFLPs and haplotypes as anthropogenetic markers, particularly in distinguishing Caucasoids from Negroids, has been discussed.     

Polynesian dentition

The chance discovery of a paper by Rottstock et al. (1983) comparing the individual diameters of 4,497 teeth from 711 skulls from anthropologically-different populations (Europeans, Negroids, Mongoloids, Melanesians) provided the impetus to add our measurements of 449 teeth from 89 Polynesians (mainland Maoris, Chatham Island, Wairau Bar) to the series. We confirm that dental measurements provide clear differences among the different population groups. We confirm that dental indices are useful by disclosing specific dental relationships among the different population groups.     

Alternative complement pathway of channel catfish (Ictalurus punctatus): molecular characterization, mapping and expression analysis of factors Bf/C2 and Df

The complement system is important in both innate and adaptive host defense against microbial infection in vertebrates. It contains three pathways: the classical, alternative, and lectin pathways. Complement component factors B and D are two crucial proteases in the alternative pathway. In this study, the genes of complement factors Bf/C2 and Df from channel catfish, Ictalurus punctatus were identified and characterized. Two complement factor B-related genes, Bf/C2A and Bf/C2B, and factor D gene Df were identified. Phylogenetic analysis suggested that Bf/C2A and Bf/C2B is likely orthologous to factor B and factor C2, respectively. Southern blot results suggested that these three genes are all single-copy genes in the catfish genome. The catfish Bf/C2A, Bf/C2B and Df genes were genetically mapped on linkage group 3, 20 and 29, respectively. Bf/C2A and Bf/C2B are highly expressed in liver and kidney, while Df is highly expressed in gill and spleen. After infection with Edwardsiella ictaluri, the expression of Bf/C2A, Bf/C2B and Df genes were found to be remarkably induced in the gill, liver, spleen and kidney at some sampling times, indicating that these three complement factors play a pivotal role in immune responses after the bacterial infection in catfish.     

Mapping of C2, Bf, and C4 genes to the swine major histocompatibility complex (swine leukocyte antigen)

Three miniature swine lines, inbred for swine leukocyte antigen (SLA) haplotypes, a, c, and d, and a recombinant line, haplotype g, were analyzed for possible restriction fragment length polymorphisms (RFLP) by Southern blot hybridization with human C2, factor B (Bf), and C4 specific probes. The search for RFLP by using a human C2 probe failed to reveal any variants. However, a Taq I polymorphism was identified with the human Bf probe and Bam HI and Pvu II polymorphisms were identified with the human C4 probe. Overlapping restriction fragments were found with the C2 and Bf probes, which strongly suggests close linkage of C2 and Bf genes in swine. Segregation analyses of the Bf and C4 polymorphisms indicated that the polymorphic fragments followed a Mendelian pattern of inheritance. The recombinant haplotype g, which expresses class I genes of haplotype c and class II genes of haplotype d, was shown to produce an identical RFLP pattern, by using the Bf and C4 probes, as haplotype d, but different from that of haplotype c. This indicates that there is a close association of [C4-Bf-C2] and class II genes in miniature swine. Although these data do not show conclusively the location of the [C4-Bf-C2] genes, it is hypothesized that swine [C4-Bf-C2] genes are located between the class II and class I genes, as has been demonstrated in mouse and man.     

Detection of bovine herpesvirus 1 and 5 in semen from Brazilian bulls

Bovine herpesvirus 1 (BoHV-1) and 5 (BoHV-5) are important pathogens of the respiratory and genital tract of cattle and may also affect the central nervous system and cause meningoencephalitis. Both virus types are estimated to be widely distributed in Southern Brazil. In the present study, BoHV-1 and/or BoHV-5 DNA were detected in bovine semen samples from two states of Brazil by two species-specific nested polymerase chain reactions (nPCRs). These nPCRs were used to assay 53 samples of fresh semen and 23 samples of frozen semen from breeding bulls. Viral DNA was detected in all 76 semen samples: all were positive for BoHV-5, whereas 34 of these were positive for BoHV-1 as well. Moreover, in five fresh and in 13 frozen semen samples—of a total number of 40 samples suitable for virus isolation—infectious BoHV-1 and/or BoHV-5 virus were detected. In conclusion, that both BoHV-1 and BoHV-5 were detected in bovine semen in Brazil highlighted the importance of examining bull semen in search for both agents to reduce the risk of transmitting these viruses.     

Genetic diversity and origin of leatherback turtles (Dermochelys coriacea) from the Brazilian coast

The leatherback sea turtle (Dermochelys coriacea) population that nests in Brazil is restricted to a few individuals, but high densities of pelagic individuals are observed along the southern and southeastern Brazilian coast. We investigated the diversity of the mitochondrial DNA (mtDNA) control region in order to understand the relationship between nesting and pelagic leatherbacks from Brazil and elsewhere. High-quality 711-bp sequences were generated, analyzed, and compared with published data from worldwide populations. We detected the presence of shared haplotypes between nesting and pelagic aggregates from Brazil, as well as haplotypes shared with other nesting areas from the Atlantic and Pacific. Furthermore, the use of longer control region sequences allowed the subdivision of the common Atlantic haplotype A into 3 different haplotypes (A1, A3, and A4), thus improving the resolution of mtDNA-based leatherback phylogeography. The use of longer sequences partially supported a closer association between nesting and pelagic individuals from Brazil and pointed to a complex origin for the pelagic individuals in the Brazilian coast.     

Cystic fibrosis: low frequency of DF508 mutation in 2 population samples from Rio de Janeiro, Brazil

Blood samples from 44 unrelated cystic fibrosis (CF) patients from Rio de Janeiro, Brazil, were analyzed for the 8 European CF mutations. Six homozygous and 15 heterozygous carriers of the DF508 mutation were found, corresponding to 47.7% of CF patients (allele frequency 0.3068). The G542X and G551D mutations were also observed with allele frequencies of 0.0227 and 0.0114, respectively. An analysis of the DF508 mutation in 291 randomly chosen, healthy individuals was performed, and only 3 heterozygous carriers were identified. These results show that the frequency of the DF508 allele in Rio de Janeiro is much lower than the world average; this may be due to the extremely heterogeneous ethnic admixture of the study population. By combining the results of these 2 different samples (CF patients and random population) and admixture data from Rio de Janeiro, we can estimate the CF incidence in this population to be 1:3542 individuals. However, taking into account the Rio de Janeiro ethnic admixture, we can find an estimate of 1:6902 individuals.