Genetic diversity of Hypostomus ancistroides (Teleostei, Loricariidae) from an urban stream

In this study, random amplified polymorphic DNA (RAPD) markers were applied to analyze the genetic diversity of samples of the Neotropical catfish Hypostomus ancistroides, collected from four sites (S1, S2, S3 and S4) along an urban stream in Southern Brazil. The 11 primers used in RAPD analysis amplified 147 loci, 76 (51.7 percent) of which were polymorphic. The proportions of polymorphic loci observed in the four samples were: 29.93 percent (S1), 31.97 percent (S2), 23.81 percent (S3) and 38.77 percent (S4). The average heterozygosity within sampling localities ranged from 0.1230 to 0.1526 and unbiased genetic distances ranged from 0.0253 to 0.0445. AMOVA partitioned 90.85 percent of the total variation within samples and 9.15 percent among samples. Excepting for the sample pair S1-S2 (phiST = 0.02784; p > 0.05), all others pairwise phiST values were significantly greater than zero, indicating moderate genetic differentiation among catfish samples from four localities. The relative low levels of genetic variation detected in all groups studied could be related to different factors, including the sedentary habit of these fish, which can be eroding the genetic variation of H. ancistroides from each locality.

Evaluation of the RAPD profiles from different body parts of Euglossa pleosticta Dressler male bees (Hymenoptera: Apidae, Euglossina)

In the current literature, information is scarce on which part of the adult insect body is suitable for isolation of genomic DNA for genetic analysis based on DNA-markers. In this study, we evaluated RAPD profiles generated from total genomic DNA isolated from distinct body parts (head, legs, thorax + wings and abdomen) of 12 males of Euglossa pleosticta Dressler. From the total of bands analyzed, 9.0 percent did not show reproducibility. Percent variations of bands in each body segment were: 1.1 percent (head); 0.4 percent (legs); 0.8 percent (thorax/wings) and 6.7 percent (abdomen). The much higher variation (chi2one sample = 10.27; df = 1; P < 0.01) in the RAPD profiles obtained by using DNA isolated from abdomen of the euglossine males suggests that this body part of adult insects should be avoided in DNA extraction procedures. Conversely, the low variation among the RAPD profiles obtained from amplifications of genomic DNA extracted from head, legs and thorax/wings indicates that all these body parts of male bees are equally useful and secure for using in isolation and amplification procedures of total genomic DNA.

Na literatura atual, são escassas as informações sobre qual a parte do corpo do inseto adulto é mais adequada para a extração de DNA genômico para estudos de análises genéticas baseadas em marcadores de DNA. Neste estudo, foram analisados os perfis de RAPD produzidos a partir da amplificação do DNA genômico extraído de partes distintas do corpo (cabeça, pernas, tórax + asas e abdome) de 12 machos de Euglossa pleosticta Dressler. Do total de bandas analisadas, 9,0 por cento não mostraram repetibilidade. As porcentagens de variação de bandas em relação às diferentes partes do corpo das abelhas foram: 1,1 por cento (cabeça); 0,4 por cento (pernas); 0,8 por cento (tórax/asas) e 6,7 por cento (abdome). A maior variação observada (chi2para uma amostra = 10,27; gl = 1; P < 0,01), nos perfis eletroforéticos de RAPD, produzidos nas amplificações do DNA extraído do abdome de machos euglossíneos sugere que essa parte do corpo de insetos adultos deve ser evitada em procedimentos de extração de DNA. De modo diverso, a baixa variação entre os perfis de RAPD obtidos a partir das amplificações de DNA genômico extraído da cabeça, pernas e tórax/asas das abelhas indica que todas essas partes do corpo de machos euglossíneos são igualmente úteis e confiáveis para serem utilizadas para a extração e a amplificação do DNA genômico.

Genetic similarity among male bees of Euglossa truncata Rebêlo & Moure (Hymenoptera: Apidae) revealed by RAPD markers

The genetic RAPD (random amplified polymorphic DNA) markers have been used successfully in taxonomical studies of several groups of organisms. In the present study these molecular markers were used to analyze the genetic similarity among eighteen males of Euglossa truncata Rebêlo & Moure exhibiting variations in two morphological characters (colour of the antennal scape and metaepisternal hairs) which are frequently used to identify this species of euglossine bee. The twelve primers used in the RAPD analysis amplified 127 loci, of which 40 (31.5 percent) were polymorphic, showing some variation among the individuals. The coefficients of genetic similarity among the individuals ranged from 0.79 to 0.95, indicating a rather high genetic similarity among the 18 male bees studied. No RAPD band was specific to any morphological character analyzed. The results indicate that all bees analyzed belong to the same species. The high genetic similarity among the eighteen euglossine males studied indicates that the variations observed in the morphological characters are not in disagreement with the identification of this species of Euglossina and these characters can vary among males of E. truncata.

Os marcadores genéticos RAPD (DNA polimórfico amplificado ao acaso) têm sido empregados com sucesso em estudos taxonômicos de diversos grupos de organismos. No presente trabalho esses marcadores moleculares foram utilizados para analisar a similaridade genética entre dezoito machos de Euglossa truncata Rebêlo & Moure apresentando variações em dois caracteres morfológicos (coloração do escapo antenal e da pilosidade dos tufos metaepisternais), os quais normalmente são utilizados na identificação dessa espécie de abelha Euglossina. Os 12 primers utilizados nas análises produziram 127 locos de RAPD, dos quais 40 (31,5 por cento) foram polimórficos, revelando alguma variação genética entre os indivíduos analisados. Os coeficientes de similaridade genética entre os indivíduos variaram de 0,79 a 0,95, indicando alta similaridade entre os 18 machos analisados. Nenhuma banda de RAPD mostrou-se específica para os caracteres morfológicos considerados. Os resultados obtidos indicam que todos os machos analisados pertencem à mesma espécie euglossina. A alta similaridade genética entre os dezoito machos eulossíneos indica que as variações observadas nos caracteres morfológicos destes não estão em discordância com a identificação dessa espécie de Euglossina, e que tais caracteres podem variar entre os machos de E. truncata.

Genetic structure analysis of Eufriesea violacea (Hymenoptera, Apidae) populations from southern Brazilian Atlantic rainforest remnants

Random amplified polymorphic DNA (RAPD) markers were used to analyze the genetic structure of Eufriesea violacea populations in three fragments (85.47, 832.58 and 2800 ha) of Atlantic rainforest located in the north of the Brazilian state of Paraná. A total of twelve primers produced 206 loci, of which 129 were polymorphic (95 percent criterion). The proportions of polymorphic loci in each population ranged from 57.28 percent to 59.2 percent, revealing very similar levels of genetic variability in the groups of bees from each fragment. Unbiased genetic distances between groups ranged from 0.0171 to 0.0284, the smallest genetic distance occurring between bees from the two larger fragments. These results suggest that the E. violacea populations from the three fragments have maintained themselves genetically similar to native populations of this species originally present in northern Paraná.