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Genetics and Molecular Biology, Volume: 28, Issue: 4, Published: 2005
  • Patterns of molecular evolution in pathogenesis-related proteins Human And Medical Genetics

    Scherer, Nicole M.; Thompson, Claudia E.; Freitas, Loreta B.; Bonatto, Sandro L.; Salzano, Francisco M.

    Abstract in English:

    The genes encoding 13 classes of pathogenesis-related (PR) proteins were examined for positive selection using maximum-likelihood (ML) models of codon substitution. The study involved 194 sequences from 54 species belonging to 37 genera. Although the sizes of the sequences examined varied from 237 bp for PR12 to 1,110 bp for PR7, most classes (9 out of 13) contained sequences made up of more than 400 nucleotides. Signs of positive selection were obtained for sites in PR proteins 4, 6, 8, 9 and 15 using an ML-based Bayesian method and likelihood ratio tests. These results confirm the importance of positive selection in proteins related to defense mechanisms already observed in a wide array of organisms.
  • Cytogenetic study of Brazilian patients with myelodysplastic syndrome (MDS) Human And Medical Genetics

    Borgonovo, Tamara; Ribeiro, Enilze M.S.F.; Cornélio, Déborah Afonso; Schmid-Braz, Ana Teresa; Jamur, Valderez Ravaglio; Wuicik, Lismeri; Veiga, Loraine Beatriz Acosta; Ehmke, Néria A. Maia; Pasquini, Ricardo; Cavalli, Iglenir João

    Abstract in English:

    Bone marrow cytogenetic studies were performed on 93 patients with primary myelodysplastic syndrome (MDS) diagnosed at the Clinical Hospital of the Federal University of Paraná, Brazil. Chromosomal alterations were observed in 69% of the patients. Monosomy of chromosome 7, deletions of 7q, 5q, 12p and 20q, rearrangements of 11q23 and trisomies of chromosomes 8 and 21 were the most frequent abnormalities observed. Among adult patients the most frequent aberrations were rearrangements of 11q23 and 12p deletions. In the pediatric group, 5q deletions and monosomy of chromosome 7 were the most common alterations.
  • The cuttable C-related genotype and allele for the E-cadherin 3’-UTR Pml I polymorphism are associated with higher susceptibility to endometriosis Human And Medical Genetics

    Hsieh, Yao-Yuan; Chang, Chi-Chen; Tsai, Fuu-Jen; Hsu, Chin-Moo; Lin, Cheng-Chieh; Tsai, Chang-Hai

    Abstract in English:

    Epithelial cadherin (E-cadherin; CDH1) may influence pericellular proteolysis and intracellular signal transduction, which plays an essential part of tumor invasion. In our study we investigated the correlation between CDH1 gene polymorphism and endometriosis in two groups of pre-menopausal Taiwanese women, group 1 (n = 150) consisting of women with severe stage IV endometriosis and group 2 (n = 159) of women with no endometriosis. The polymerase chain reaction (PCR) was used to identify the cuttable (C) and uncuttable (T) polymorphism of the CDH1-Pml I gene (rs1801026) located on the 3’-untranslated region (3’-UTR) of chromosome 16 and compare the genotypes and allelic frequencies of this gene in both groups. We found that the genotype and allele distributions of the CDH1-Pml I C/T polymorphism were significantly different in both groups. In group 1 the CDH1*C frequency was 47.7% and the T frequency 52.3%, while the CC homozygote frequency was 6.7%, the TT homozygote 11.3% and the CT heterozygote 82%. In group 2 the CDH1*C frequency was 17% and the T frequency 83%, while the CC frequency was 0.6%, the TT 66.1% and the CT 33.3%. These data indicate that the CDH1 gene polymorphism may be associated with the development of severe endometriosis and that the CDH1 gene C allele is related to higher susceptibility to endometriosis.
  • Frequencies of CCR5-D32, CCR2-64I and SDF1-3’A mutations in Human Immunodeficiency Virus (HIV) seropositive subjects and seronegative individuals from the state of Pará in Brazilian Amazonia Human And Medical Genetics

    Carvalhaes, Fernanda Andreza de Pinho Lott; Cardoso, Greice Lemos; Vallinoto, Antonio Carlos Rosário; Machado, Luiz Fernando; Ishak, Marluisa de Oliveira Guimarães; Ishak, Ricardo; Guerreiro, João Farias

    Abstract in English:

    The distribution of genetic polymorphisms of chemokine receptors CCR5-delta32, CCR2-64I and chemokine (SDF1-3’A) mutations were studied in 110 Human Immunodeficiency Virus type 1 (HIV-1) seropositive individuals (seropositive group) and 139 seronegative individuals (seronegative group) from the population of the northern Brazilian city of Belém which is the capital of the state of Pará in the Brazilian Amazon. The CCR5-delta32 mutation was found in the two groups at similar frequencies, i.e. 2.2% for the seronegative group and 2.7% for the seropositive group. The frequencies of the SDF1-3’A mutation were 21.0% for the seronegative group and 15.4% for the seropositive group, and the CCR2-64I allele was found at frequencies of 12.5% for the seronegative group and 5.4% for the seropositive group. Genotype distributions were consistent with Hardy-Weinberg expectations in both groups, suggesting that none of the three mutations has a detectable selective effect. Difference in the allelic and genotypic frequencies was statistically significant for the CCR2 locus, the frequency in the seronegative group being twice that found in the seropositive group. This finding may indicate a protective effect of the CCR2-64I mutation in relation to HIV transmission. However, considering that the CCR2-64I mutation has been more strongly associated with a decreased risk for progression for AIDS than to the resistance to the HIV infection, this could reflect an aspect of population structure or a Type I error.
  • Quantitative trait locus affecting birth weight on bovine chromosome 5 in a F2 Gyr x Holstein population Animal Genetics

    Gasparin, Gustavo; Miyata, Marcelo; Coutinho, Luiz Lehmann; Martinez, Mário Luiz; Silva, Marcos Vinícius G. Barbosa da; Machado, Marco Antônio; Campos, Ana Lúcia; Regitano, Luciana Correia de Almeida

    Abstract in English:

    Segregation between a genetic marker and a locus influencing a quantitative trait in a well delineated population is the basis for success in mapping quantitative trait loci (QTL). To detect bovine chromosome 5 (BTA5) birth weight QTL we genotyped 294 F2 Gyr (Bos indicus) x Holstein (Bos taurus) crossbreed cattle for five microsatellite markers. A linkage map was constructed for the markers and an interval analysis for the presence of QTL was performed. The linkage map indicated differences in the order of two markers relative to the reference map (<A HREF="http://www.marc.usda.gov/">http://www.marc.usda.gov</A>). Interval analysis detected a QTL controlling birth weight (p < 0.01) at 69 centimorgans (cM) from the most centromeric marker with an effect of 0.32 phenotypic standard-error. These results support other studies with crossbred Bos taurus x Bos indicus populations.
  • Mitochondrial DNA D-loop sequence variation among 5 maternal lines of the Zemaitukai horse breed Animal Genetics

    Cothran, E. Gus; Juras, Rytis; Macijauskiene, Vale

    Abstract in English:

    Genetic variation in Zemaitukai horses was investigated using mitochondrial DNA (mtDNA) sequencing. The study was performed on 421 bp of the mitochondrial DNA control region, which is known to be more variable than other sections of the mitochondrial genome. Samples from each of the remaining maternal family lines of Zemaitukai horses and three random samples for other Lithuanian (Lithuanian Heavy Draught, Zemaitukai large type) and ten European horse breeds were sequenced. Five distinct haplotypes were obtained for the five Zemaitukai maternal families supporting the pedigree data. The minimal difference between two different sequence haplotypes was 6 and the maximal 11 nucleotides in Zemaitukai horse breed. A total of 20 nucleotide differences compared to the reference sequence were found in Lithuanian horse breeds. Genetic cluster analysis did not shown any clear pattern of relationship among breeds of different type.
  • Nine karyomorphs for spiny rats of the genus Proechimys (Echimyidae, Rodentia) from North and Central Brazil Animal Genetics

    Machado, Taís; Silva, Maria José de J.; Leal-Mesquita, Emygdia Rosa; Carmignotto, Ana Paula; Yonenaga-Yassuda, Yatiyo

    Abstract in English:

    Spiny rats of the genus Proechimys are morphologically diverse, widely distributed and have diploid numbers ranging from 2n = 14-16 to 2n = 62. In this paper we present cytogenetical data and brief comments on morphological and biogeographical issues related to spiny rats. In our sample of 42 spiny rats collected from 12 Brazilian Amazonian tropical rainforest and the Cerrado (Brazilian savanna) sites we detected nine karyological entities: four different karyomorphs with 2n = 30, three with 2n = 28, one with 2n = 15 and one with 2n = 44. Based on qualitative morphological characters these karyomorphs can be allocated to five species within the goeldii, guyannensis and longicaudatus species groups.
  • Population structure and genetic variability of mainland and insular populations of the Neotropical water rat, Nectomys squamipes (Rodentia, Sigmodontinae) Animal Genetics

    Almeida, Francisca C.; Maroja, Luana S.; Moreira, Miguel A.M.; Seuánez, Héctor N.; Cerqueira, Rui

    Abstract in English:

    Seven microsatellite loci were used to investigate the genetic variability and structure of six mainland and two island populations of the Neotropical water rat Nectomys squamipes, a South American semi-aquatic rodent species with a wide distribution. High levels of variability were found within mainland populations while island populations were less variable but the more differentiated in respect to allele number and frequency. The time of biological divergence between mainland and island populations coincided with geological data. A significant geographic structure was found in mainland populations (theta = 0.099; rho = 0.086) although the degree of differentiation was relatively low in respect to the distance between surveyed localities (24 to 740 km). Genetic and geographic distances were not positively correlated as previously found with random amplified polymorphic DNA (RAPD) markers. Significant but low genetic differentiation in the mainland and lack of isolation by distance can be explained by large population size and/or recent population expansion. Additionally, the agreement between the age of geologic events (sea level fluctuations) and divergence times for insular populations points to a good reference for molecular clock calibration to associate recent environmental changes and the distribution pattern of small mammals in the Brazilian Atlantic Forest.
  • Chromosomal banding patterns in the eyelid-less microteiid lizard radiation: The X1X1X2X2:X1X2Y sex chromosome system in Calyptommatus and the karyotypes of Psilophthalmus and Tretioscincus (Squamata, Gymnophthalmidae) Animal Genetics

    Yonenaga-Yassuda, Yatiyo; Rodrigues, Miguel Trefaut; Pellegrino, Katia Cristina Machado

    Abstract in English:

    Cytogenetic studies were performed on five closely related microteiid lizards (Gymnophthalmini), three Calyptommatus species and Psilophthalmus paeminosus from the sand dunes of the middle São Francisco river in the semiarid caatinga of the Brazilian state of Bahia and Tretioscincus oriximinensis from the Brazilian Amazon region. The diploid chromosome number in Calyptommatus species was 2n = 58 in females and 2n = 57 in males due to a multiple X1X1X2X2:X1X2Y sex chromosomes system, while P. paeminosus was 2n = 44 (20M+24m): where M = macrochromosomes and m = microchromosomes) and T. oriximinensis 2n = 42 (18M+24m). A single pair of silver staining nucleolar organizing regions (Ag-NORs) characterizes all five species. Incorporation of 5-BrdU (Bromodeoxyuridine) followed by replication R-banding (RBG) karyotyping allowed the identification of the larger pairs of chromosomes through longitudinal bands and the late replicating regions. Our data reinforce the remarkable chromosomal variability that has been found in the Gymnophthalmidae and the importance of using differential staining for comparative cytogenetics within this group of lizards. Chromosomal evolution in Gymnophthalmini seems to have included chromosomal fission and fusion, pericentric inversions and variation in the amount and localization of constitutive heterochromatin and the Ag-NOR pattern. Different mechanisms of sex determination also evolved independently in this radiation.
  • Cytotaxonomy of Parodon nasus and Parodon tortuosus (Pisces, Characiformes): A case of synonymy confirmed by cytogenetic analyses Animal Genetics

    Bellafronte, Elisangela; Margarido, Vladimir Pavan; Moreira-Filho, Orlando

    Abstract in English:

    Morphological and cytogenetical studies were carried out on the freshwater fish Parodon nasus and Parodon tortuosus in order to evaluate a putative synonymy. The diploid chromosome number observed in both species was 2n = 54 (48M/SM and 6ST) with no differences between the sexes. Despite slight differences in the pattern of heterochromatin distribution and the number of cusps in symphysean teeth, the location of nucleolar organizer regions (NORs) and 5S rRNA genes (both species-specific features) were similar in both species. The remarkable similarity observed between these allopatric species supports recent taxonomical reviews indicating that P. tortuosus is a synonym for P. nasus.
  • Genetic variability in Astyanax altiparanae Garutti & Britski, 2000 (Teleostei, Characidae) from the Upper Paraná River basin, Brazil Animal Genetics

    Peres, Maria Dolores; Vasconcelos, Marcio dos Santos; Renesto, Erasmo

    Abstract in English:

    Allozyme data was used to assess the genetic diversity Astyanax altiparanae populations from the floodplain of the Upper Paraná River (PR). Specimens were collected in the southern Brazilian state of Paraná from PR in Porto Rico municipality and Ribeirão Ficha (RF) in Ubiratã municipality. The authors used 15% (w/v) corn starch gel electrophoresis to identify 21 putative loci for 13 enzymatic systems: Aspartate aminotransferase, 2.6.1.1 (AAT), Acid phosphatase, 3.1.3.2 (ACP), Esterase, 3.1.1.1 (EST), Glycerol-3-phosphate dehydrogenase, 1.1.1.8 (G3PDH), Glucose-6-phosphate dehydrogenase, 1.1.1.49 (G6PDH), Glucose-6-phosphate isomerase, 5.3.1.9 (GPI), Iditol dehydrogenase, 1.1.1.14 (IDDH), Isocitrate dehydrogenase - NADP+, 1.1.1.42 (IDH), L-Lactate dehydrogenase, 1.1.1.27 (LDH), Malate dehydrogenase, 1.1.1.37 (MDH), Malate dehydrogenase - NADP+, 1.1.1.40 (MDHP), Phosphoglucomutase, 5.4.2.2 (PGM), and Superoxide dismutase, 1.15.1.1 (SOD). The proportion of polymorphic loci were estimated as 52.38% in the PR population and 38.10% in the RF population. Expected estimated heterozygosities were 0.1518 ± 0.0493 for the PR population and 0.0905 ± 0.0464 for the RF population. The A. altiparanae heterozygosity data were similar to previous estimates for other PR basin characid species. Allele frequencies were significantly different between the PR and RF populations in respect to some loci (Acp-1, G3pdh-1, Gpi-A, Iddh-1, Mdhp-1 and Mdhp-2). Wright’s statistics for all loci were estimated as Fis = 0.3919, Fit = 0.4804 and Fst = 0.1455. Our results show that the A. altiparanae populations studied are genetically different and have a high degree of genetic variability.
  • Chromosome evolution in tiger beetles: Karyotypes and localization of 18S rDNA loci in Neotropical Megacephalini (Coleoptera, Cicindelidae) Animal Genetics

    Proença, Sónia J.R.; Collares-Pereira, Maria João; Serrano, Artur R.M.

    Abstract in English:

    Four Neotropical tiger beetle species, three from the genus Megacephala and one from the genus Oxycheila, currently assigned to the tribe Megacephalini were examined cytogenetically. All three Megacephala species showed simple sex chromosome systems of the X0/XX type but different numbers of autosomal pairs (15 in M. cruciata, 14 in M. sobrina and 12 in M. rutilans), while Oxycheila tristis was inferred to have a multiple sex chromosome system with four X chromosomes (2n = 24 + X1X2X3X4Y/X1X1X2X2X3X3X4X4). Fluorescence in situ hybridization (FISH) using a PCR-amplified 18S rDNA fragment as a probe revealed the presence of rDNA clusters located exclusively on the autosomes in all the Megacephala species (five clusters in M. cruciata, eight in M. sobrina and three in M. rutilans), indicating variability in the number of clusters and the presence of structural polymorphisms. The same methodology showed that O. tristis had six rDNA clusters, apparently also located on the autosomes. Although our data also show cytogenetic variability within the genus Megacephala, our findings support the most accepted hypothesis for chromosome evolution in the family Cicindelidae. The description of multiple sex chromosomes in O. tristis along with phylogenetic analyses and larval morphological characters may be assumed as an additional evidence for the exclusion of the genus Oxycheila and related taxa from the tribe Megacephalini.
  • Transposable elements P and gypsy in natural populations of Drosophila willistoni Animal Genetics

    Sassi, Adriana Koslovski; Herédia, Fabiana; Loreto, Élgion Lucio da Silva; Valente, Vera Lucia da Silva; Rohde, Claudia

    Abstract in English:

    The presence and integrity of the P transposon and the gypsy retrotransposon in the genome of 18 samples of natural Drosophila willistoni populations collected from a large area of South America were Southern blot screened using Drosophila melanogaster probes. The aim of this screening was provide further knowledge-base on the geographical distribution of D. willistoni and to carry out an inter-population analysis of the P and gypsy elements present in the genomes of the populations analyzed. The fragment patterns obtained indicate that both the P and gypsy elements are ancient in the D. willistoni genome, but whereas the gypsy retroelement appears to be invariable and stable the P element varies between populations and appears to still have some capacity for mobilization.
  • DNA polymorphism of leptin gene in Bos indicus and Bos taurus cattle Animal Genetics

    Choudhary, Vivek; Kumar, Pushpendra; Bhattacharya, Tarun K.; Bhushan, Bharat; Sharma, Arjava

    Abstract in English:

    Leptin plays an important role in the regulation of feed intake, energy metabolism, growth and reproduction of cattle. We used the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique to screen for DNA polymorphisms of the leptin gene in 403 cattle belonging to various breeds of Bos indicus (Hariana, Sahiwal, Gir and Nimari cattle), Bos taurus (Holstein Friesian (HF) and Jersey cattle) as well as Bos taurus x Bos indicus crossbreds (½ HF x ½ Hariana). In all the cattle we amplified two regions of the leptin gene, a 522 bp fragment comprising the partial intron 2 and exon 3 and another 94 bp fragment consisting of part of exon 2. Digestion of 522 bp PCR products with the BsaAI restriction enzyme revealed three genotypes in all the breeds of cattle studied. This is the first report of the presence of leptin gene polymorphism in purebred Bos indicus cattle of Indian origin (indicine cattle). Almost similar gene and genotype frequencies were observed in all the breed groups, while the frequency of mutant homozygotes (AA) was very low (0.03 to 0.07). On digestion of the 94 bp fragment with the Kpn2I restriction enzyme, three genotypes were observed in HF, Jersey and crossbred cattle. The CC genotype had the highest frequency (0.68) in crossbreds whereas the frequency of CT heterozygotes was highest (0.69) in HF cattle. This mutation was absent in all the breeds of indicine cattle. The results suggest that the BsaAI-RFLP mutation has occurred far back in evolution before the divergence of taurine and indicine cattle while the Kpn2I mutation has occurred recently as indicated by the fact that this mutation was only detected in taurine cattle.
  • Genome size of three Brazilian flies from the Sciaridae family Animal Genetics

    Saccuti, Cecília Ferreira; Soares, Maria Albertina de Miranda; Falco, José Ricardo Penteado; Fernandez, Maria Aparecida

    Abstract in English:

    We determined the genome size of the Brazilian sciarid flies Bradysia hygida, Rhynchosciara americana and Trichosia pubescens (Diptera: Sciaridae) using absorbance measurements of Feulgen-stained nuclei belonging to these species (and chicken erythrocytes as a standard) to calculate the amount of DNA in picograms (pg) and the number of base pairs (bp), or C-value, for each of these species. The C-values were: 3 x 10(8) bp (0.31 pg) for B. hygida; 3.6 x 10(8) bp (0.37 pg) for R. americana; and 1 x 10(9) bp (1.03 pg) for T. pubescens. The sciarids investigated in this work had considerably higher C-values than the average for previously described dipteran species, including D. melanogaster.
  • Esterase profile in a pyrethroid-resistant Brazilian strain of the cattle tick Boophilus microplus (Acari, Ixodidae) Animal Genetics

    Baffi, Milla Alves; Pereira, Cícero Donizete; Souza, Guilherme Rocha Lino de; Bonetti, Ana Maria; Ceron, Carlos Roberto; Gourlart, Luiz Ricardo

    Abstract in English:

    The cattle tick Boophilus microplus causes great damage in livestock and is considered one of the most important tropical ectoparasites. The traditional method of control is based on the intensive use of pesticides, however the indiscriminate use of these compounds over the years has led to the selection of resistant ticks. Hydrolases, particularly esterases (EST), have been reported to be associated with acaricide resistance in B. microplus. We compared the esterase profile of susceptible and cypermethrin-resistant strains of adult B. microplus and a pyrethroid susceptible reference strain (the Mozzo strain) using polyacrylamide gel electrophoresis and specific staining. The electrophoretic profiles of protein extracts revealed the presence of four regions with esterase activity in the cypermethrin-resistant strain and three of these regions in the susceptible strains. The bands were numbered EST-1 to EST-4 in sequence (starting from the anode) according to their decrease in negative charge. The EST-1A and EST-1B enzymes were detected only in the resistant strain. The inhibition studies with eserine sulfate, copper sulfate, p- p-chloromercuribenzoate (pCMB), malathion and phenylmethylsulfonyl fluoride (PMSF) indicated that the EST-1A and EST-1B enzymes belong to the acetylcholinesterase class and are probably associated with resistance to acaricides in this Brazilian resistant strain of B. microplus.
  • Nuclear DNA content and karyotype of Rosewood (Aniba rosaeodora) Plant Genetics

    Contim, Luis Antônio Serrão; Carvalho, Carlos Roberto de; Martins, Franciele Alline; Freitas, Danival Vieira de

    Abstract in English:

    Rosewood (Aniba rosaeodora Ducke, Lauraceae) is ecologically and economically important to the Amazon region. As a consequence of its economic importance, rosewood populations have been decimated in the Amazon forest. Species of nine genera of the Lauraceae family have characterized karyotypes with n = x = 12 chromosomes in the gametophytic phase but the genus Aniba is one of the least studied Lauraceae genera with a previously undescribed genome. We used cytogenetic techniques to determine that the A. rosaeodora karyotype contained 12 pairs (2n = 24) of relatively small submetacentric chromosomes with lengths ranging from 1.34 to 2.25 mum and a nucleolar organizer region (NOR) in the short arm of chromosome 7. Flow cytometry gave 2C = 2.32 pg of DNA, equivalent to approximately 2.24 x 10(9) base pairs.
  • Age-age correlation for early selection of rubber tree genotypes in São Paulo State, Brazil Plant Genetics

    Gonçalves, Paulo de Souza; Bortoletto, Nelson; Cardinal, Átila Bento Beleti; Gouvêa, Lígia Regina Lima; Costa, Reginaldo Brito da; Moraes, Mário Luiz Teixeira de

    Abstract in English:

    In a field trial involving 68 rubber tree (Hevea spp.) clones calculation of genotypic correlation coefficients revealed significant age-age correlation from age 1 to 6 (immature period) for girth A and for age 7 to 12 (mature period) for girth B and for age 7 to 12 (production of latex) for yield. Rank correlation coefficients between all immature ages of girth (girth A), all ages of mature girth (girth B) and all annual rubber production (yield) were significant for the three traits, with the coefficients decreasing with increasing age. Selection of the sets of best 30, 15, 10 and 5 clones from the available 68 clones at a given age was generally accompanied by a descending order of percentage success. It was suggested: (a) to have the best 30 clones of age 6, select the set of best 36 clones at age 2, (b) to have the best 15 clones of age 6, select the set of best 20 clones at age 3, (c) to have the best 5 clones of age 6, select the set of best 8 clones at age 4, and (d) to have the best 3 clones of age 6, select the set of best 3 clones at age 5. More than 80% of the targeted clones on girth A or girth B basis and more than 76.7% clones on yield basis were found to get selected at steps (a) through (d). For achieving early multiplication of the most productive clone for deployment, multiplication should be started with the best 36 (i.e. 60%) clones selected at age 2.
  • Genetic variation in growth traits and yield of rubber trees (Hevea brasiliensis) growing in the Brazilian state of São Paulo Plant Genetics

    Gonçalves, Paulo de Souza; Moraes, Mário Luiz Teixeira de; Bortoletto, Nelson; Costa, Reginaldo Brito da; Gonçalves, Elaine Cristine Pifer

    Abstract in English:

    Analysis of variance and covariance was preformed on growth traits (stem girth, bark thickness, total height gain and rubber yield) of 22 open-pollinated progenies of the rubber tree Hevea brasiliensis from an Asian Hevea collection introduced to Agronomic Institute (Instituto Agronômico, Campinas, São Paulo, Brazil; IAC) in 1952. This progeny trial was replicated at three sites in São Paulo state and it was found that at three years from sowing there was statistically significant variation for girth, bark thickness, height and rubber yield. An individual test sites, values of individual plant heritability for girth ranged from h= 0.36 to h= 0.89 whereas values for heritability for progeny means ranged from h= 0.77 to h= 0.87. These moderate and high heritabilities suggest that a combination of progeny and within-progeny selection would be effective at increasing girth in this population at individual sites. Across sites, values of individual-plant heritability for girth ranged from h= 0.36 to h= 0.47, whereas values for heritability of progeny means girth ranged from h= 0.77 to h= 0.87. There were high positive genetic correlations between increased girth and bark thickness suggesting that breeding aimed at increasing girth would also increase bark thickness and possibly height.
  • Chromosome numbers and meiotic behavior of some Paspalum accessions Plant Genetics

    Adamowski, Eleniza de Victor; Pagliarini, Maria Suely; Bonato, Andréa Beatriz Mendes; Batista, Luiz Alberto Rocha; Valls, José Francisco Montenegro

    Abstract in English:

    Chromosome number and meiotic behavior were evaluated in 36 Brazilian accessions of the grass Paspalum (which had never previously been analyzed) to determinate which accessions might be useful in interspecific hybridizations. The analysis showed that one accession of Paspalum coryphaeum was diploid (2n = 2x = 20) and one accession of Paspalum conspersum hexaploid (2n = 6x = 60), the remaining 34 accessions being tetraploid (2n = 4x = 40). The pairing configuration was typical for the ploidy level i.e. in the diploid, chromosomes paired as 10 bivalents, in tetraploids as bi-, tri- and quadrivalents, and in hexaploid as 30 bivalents. A low frequency of meiotic abnormalities (less than 10%) was observed in the diploid, hexaploid and some tetraploid accessions, although the majority of tetraploid accessions showed a high frequency of meiotic irregularities. The use of accessions with a low frequency of meiotic abnormalities in breeding programs is discussed.
  • Responses to reciprocal recurrent selection and changes in genetic variability in IG-1 and IG-2 maize populations Plant Genetics

    Santos, Mateus Figueiredo; Moro, Gustavo Vitti; Aguiar, Aurélio Mendes; Souza Jr., Cláudio Lopes de

    Abstract in English:

    This paper reports the effects of three cycles of reciprocal recurrent selection (RRS) on the means, genetic variances, and on the genetic correlations for several traits in the IG-1 and IG-2 maize (Zea mays L.) populations. Interpopulation full-sib progenies from cycle zero (C0) and from cycle 3 (C3) of RRS were evaluated in two locations. RRS was highly effective to improve the traits according the objectives of the program: grain yield and prolificacy increased significantly, while plant height, ear height, and ear placement decreased significantly. Genetic variances for all traits decreased significantly from C0 to C3, but the genetic correlations did not change consistently across the cycles of selection. The expected responses to the fourth cycle of RRS and the probability of selecting double-crosses from C3 that outperform those from C0 showed that the decreases in the genetic variances were not great enough to limit the continued improvement of the populations as well as the use of the improved populations as sources of inbred lines to develop commercial hybrids. However, if the magnitudes of the genetic variances continue to decrease, new sources of improved germplasm should be incorporated into both populations to allow the continued improvement of the interpopulation by RRS.
  • Microsatellite-assisted backcross selection in maize Plant Genetics

    Benchimol, Luciana Lasry; Souza Jr., Cláudio Lopes de; Souza, Anete Pereira de

    Abstract in English:

    A microsatellite marker (SSR) was chosen to simulate a target allele and three criteria (02, 04 and 06 markers per chromosome) were tested to evaluate the most efficient parameters for performing marker-assisted backcross (MAB) selection. We used 53 polymorphic SSRs to genotype 186 BC1 maize (Zea mays L.) plants produced by crossing the inbred maize lines L-08-05 (donor parent) and L-14-4B (recurrent parent). The second backcross (BC2) generation was produced with 180 plants and screened with markers which were not recovered from the first backcross (BC1) generation. A total of 480 plants were evaluated in the third backcross (BC3) generation from which 48 plants were selected for parental genotype recovery. Recurrent genotype recovery averages in three backcross generations were compatible with those expected in BC4 or BC5, indicating genetic gain due to the marker-assisted backcrossing. The target marker (polymorphic microsatellite PHI037) was efficiently transferred. Six markers per chromosome showed a high level of precision for parental estimates at different levels of maize genome saturation and donor alleles were not present in the selected recovered pure lines. Phenotypically, the plants chosen based on this criterion (06 markers per chromosome) were closer to the recurrent parent than any other selected by other criteria (02 or 04 markers per chromosome). This approach allowed the understanding that six microsatellites per chromosome is a more efficient parameter than 02 and 04 markers per chromosome for deriving a marker-assisted backcross (MAB) experiment in three backcross generations.
  • Genotoxic evaluation of sodium nitroprusside in Aspergillus nidulans Genetics Of Microorganisms

    Chiuchetta, Simone Jurema Ruggeri; Castro-Prado, Marialba Avezum Alves de

    Abstract in English:

    The exogenous nitric oxide donor, sodium nitroprusside, evaluated the recombinogenic potential of nitric oxide. Drug inhibited mycelial growth and conidiation in A757 Aspergillus nidulans master strain. Two heterozygous diploid strains, one wild (uvsH+//uvsH+) and the other defective to DNA repair (uvsH//uvsH) were used for recombinagenesis tests. Sodium nitroprusside recombinogenic effect was evaluated by the induction of homozygosis of recessive genes, originally present in heterozygous condition. Results show that sodium nitroprusside (40 muM, 80 muM and 160 muM) is effective in inducing mitotic crossing-over in diploid cells of A. nidulans.
  • The biology and potential for genetic research of transposable elements in filamentous fungi Genetics Of Microorganisms

    Fávaro, Léia Cecilia de Lima; Araújo, Welington Luiz de; Azevedo, João Lúcio de; Paccola-Meirelles, Luzia Doretto

    Abstract in English:

    Recently many transposable elements have been identified and characterized in filamentous fungi, especially in species of agricultural, biotechnological and medical interest. Similar to the elements found in other eukaryotes, fungal transposons can be classified as class I elements (retrotransposons) that use RNA and reverse transcriptase and class II elements (DNA transposons) that use DNA. The changes (transposition and recombination) caused by transposons can supply wide-ranging genetic variation, especially for species that do not have a sexual phase. The application of transposable elements to gene isolation and population analysis is an important tool for molecular biology and studies of fungal evolution.
  • Identification in silico of putative damage responsive elements (DRE) in promoter regions of the yeast genome Genetics Of Microorganisms

    Silva, Walkiria Luckwu de Santana; Cavalcanti, Andre Ricardo de Oliveira; Guimarães, Katia Silva; Morais Jr., Marcos Antonio de

    Abstract in English:

    We report an in silico analysis to identify nucleotide sequence motifs in DNA repair genes that may define a binding site for regulatory proteins during the induction of those genes by mutagens. The damage responsive elements (DRE) weight matrix generated in this analysis was used to search for homologous sequences in the promoter region of all genes, including putative gene and hypothetical open reading frames (ORFs), in the Saccharomyces Genome Data Base (SGD). The results demonstrated that over one third of the yeast genes in the database presented at least one 15-bp sequence in their promoter region with 85% or more of similarity to the DRE consensus sequence. The presence of the DRE sequence in the promoter region of regulatory genes and its high similarity to other well reported DNA binding sites points to its involvement in the general regulation of not only DNA repair genes but yeast genes in general.
  • Cloning of the Bacillus thuringiensis serovar sotto chitinase (Schi) gene and characterization of its protein Genetics Of Microorganisms

    Zhong, Wan-Fang; Fang, Ji-Chao; Cai, Ping-Zhong; Yan, Wen-Zhao; Wu, Jie; Guo, Hui-Fang

    Abstract in English:

    Chitinase plays a positive role in the pathogenicity of Bacillus thuringiensis to insect pests. We used touchdown PCR to clone the chitinase (Schi) gene from Bacillus thuringiensis serovar sotto (Bt sotto) chromosomal DNA. Our DNA sequencing analysis revealed that the Bt sotto Schi gene consists of an open reading frame (ORF) of 2067 nucleotides with codes for the chitinase precursor. We also found that the putative promoter consensus sequences (the -35 and -10 regions) of the Bt soto Schi gene are identical to those of the chiA71 gene from Bt Pakistani, the chiA74 gene from Bt kenyae and the ichi gene from Bt israelensis. The Schi chitinase precursor is 688 amino acids long with an estimated molecular mass of 75.75 kDa and a theoretical isoelectric point of 5.74, and contains four domains, which are, in sequence, a signal peptide, an N-terminal catalytic domain, a fibronectin type III like domain and a C-terminal chitin-binding domain. Sequence comparison and the evolutionary relationship of the Bt sotto Schi chitinase to other chitinase and chitinase-like proteins are also discussed.
  • Analysis of genetic susceptibility to mercury contamination evaluated through molecular biomarkers in at-risk Amazon Amerindian populations Mutagenesis

    Klautau-Guimarães, Maria de Nazare; D’Ascenção, Renata; Caldart, Fabiana A.; Grisolia, Cesar K.; Souza, Jurandir R. de; Barbosa, Antonio C.; Cordeiro, Célia M.T.; Ferrari, Iris

    Abstract in English:

    We investigated Individual differences in susceptibility to methylmercury (MeHg) contamination and its relationship with polymorphisms of the detoxifying enzyme glutathione S-transferase (GST). In Brazil, some Amerindian tribes from the Amazon region have an increased level of mercury in their hair. Samples of hair and blood were taken from inhabitants of two villages in the Kayabi and Munduruku Amerindian communities to investigate mercury levels in association with genetic polymorphism of GSTs. Other molecular biological markers were also studied, such as hemoglobin, haptoglobin and glucose 6-phosphate dehydrogenase (G-6-PDH). Higher levels of mercury contamination were found in the Kayabi villagers, who had a null genotype (GSTM1 0/0, also denominated GSTM1 null) frequency of 26%, than in the Munduruku villagers, for which the null genotype frequency was 0%. Individuals with the GSTM1 null phenotype had higher concentrations of mercury in their hair than individuals with GSTM1+/+ phenotypes (F = 21.51, p < 0.0001). No association with other markers studied was observed. This study suggests that GSTM1 may be involved in the biotransformation of mercury in humans.
  • In vivo evaluation of the mutagenic potential and phytochemical characterization of oleoresin from Copaifera duckei Dwyer Mutagenesis

    Maistro, Edson Luis; Carvalho, José Carlos Tavares; Cascon, Vera; Kaplan, Maria Auxiliadora Coelho

    Abstract in English:

    We characterized the chemical constituents of Copaifera duckei oleoresin and used dermal application to Wistar rats to evaluated its possible mutagenic and cytotoxic activities on peripheral blood reticulocytes and bone marrow cells. Chemical characterization of the oleoresin revealed the presence of sesquiterpene hydrocarbons, an unidentified neutral diterpene and diterpene acids. To evaluate mutagenicity evaluation the rats were treated with 10, 25 and 50% of the LD50 dose of the oleoresin for three consecutive days and peripheral blood collected after 0, 24, 48 and 72 h for micronucleus analysis. The rats were humanly sacrificed 24 hours after the last treatment and chromosome preparations made using standard techniques. At the three concentrations and the three time intervals tested we found that there were no statistically significant differences in either the mean number of micronucleated reticulocytes (MNRETs) or the number of chromosomal aberrations as to the negative control. However, at 25 and 50% of the LD50 dose of the oleoresin there was a significant decrease in the mitotic index (MI) as compared to the negative control. Under our experimental conditions, C. duckei V11 oleoresin produced no mutagenic effects on bone marrow cells or in peripheral reticulocytes as assessed by chromosome aberrations and the micronucleus test respectively, but showed cytotoxic activity at high doses.
  • Characterization and copy number of the S27 ribosomal protein gene from amphioxus Branchiostoma belcheri tsingtauense Evolutionary Genetics

    Ma, Lifang; Zhang, Shicui; Liu, Zhenhui; Li, Hongyan; Xia, Jianjun

    Abstract in English:

    A cDNA clone encoding ribosomal protein S27 (AmphiS27) was identified in the gut cDNA library of amphioxus Branchiostoma belcheri tsingtauense. This cDNA consists of 607 bp and contains a 255 bp open reading frame (ORF) corresponding to a deduced protein of 84 amino acids with a calculated molecular mass of 9,488 Da and an isoelectric point (pI) of 9.500. Alignment of the deduced AmphiS27 amino acid sequence with 12 known S27 protein sequences indicates that AmphiS27 shares 94-99% homology with its vertebrate homologue, 84-94% with invertebrate homologues and 69-72% with homologues from other eukaryotes, suggesting that AmphiS27 is more closely related to the vertebrate S27 protein than to its invertebrate counterpart. Southern blot analysis showed a single copy of the S27 gene present in the genome of amphioxus B. belcheri tsingtauense, indicating that amphioxus has a genome uncomplicated by extensive gene duplication.
  • The quantitative genetic basis of female and male body size and their implications on the evolution of body size dimorphism in the house cricket Acheta domesticus (Gryllidae) Evolutionary Genetics

    Castillo, Raúl Cueva del

    Abstract in English:

    Few theoretical and experimental studies have analyzed the genetic basis of body size dimorphism. Since the evolutionary response to selection depends of the genetic variance in a population it is to be expected that traits under selection would have smaller genetic variance than traits not affected by selection. The evolution of sexual size dimorphism is affected by the genetic correlation between females and males, with the most dimorphic traits showing smaller genetic correlations between the sexes. As result of the differences in the intensity of sexual selection between the sexes, it is expected that the levels of genetic variance would be larger in females than males. I analyzed the genetic additive variance underlying six traits of Acheta domesticus, and the genetic correlations between females and males. The most dimorphic trait with the smallest genetic correlation between the sexes was forewing length, this trait showing genetic variance only in females. It may be that sexual selection acting on male traits has depleted the genetic variance not only in male traits but also for those female traits that have a large genetic correlation with male traits. It is also possible that the evolution of sexual dimorphism in A. domesticus could be constrained as a result of the large genetic correlation between the sexes.
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