Mestrado em Genética e Biologia Molecular (ICB)
URI Permanente para esta coleção
Navegar
Navegando Mestrado em Genética e Biologia Molecular (ICB) por Por Orientador "Collevatti, Rosane Garcia"
Agora exibindo 1 - 2 de 2
Resultados por página
Opções de Ordenação
Item Estudo filogeográfico de Micrurus lemniscatus (LINNAEUS, 1758) (SERPENTES: ELAPIDAE)(Universidade Federal de Goiás, 2014-03-10) Abreu, Tatianne Piza Ferrari; Silva Junior, Nelson Jorge da; http://lattes.cnpq.br/6544526824923185; Collevatti, Rosane Garcia; http://lattes.cnpq.br/9979596352166630; Collevatti, Rosane Garcia; Maciel, Natan Medeiros; Vaz-Silva, WilianMicrurus lemniscatus is a South American coral snake species, popularly known as “coral verdadeira”. It is widely distributed in Seasonally Dry Forests (SDF), Gallery Forests and Rainforests. The Tertiary events and the climatic oscillations of the Quaternary affected the distribution of these ecosystems altering, in turn, the distribution of animals associated to these habitats. We hypothesize that the forest expansion and contraction cycles caused by climate fluctuations may have influenced the current distribution and genetic structure of M. lemniscatus. This study aimed to study the evolutionary relationships and patterns of divergence among M. lemniscatus lineages and infer the historical biogeographic events that influenced the distribution and genetic variation. Twenty-nine individuals of M. lemniscatus were sampled from 16 localities in the states of Tocantins, Bahia, Goiás, Alagoas, Mato Grosso, Maranhão, Pará and Amazônia. Three mitochondrial regions (COI, 16S and ND4L) were sequenced, and together generated a fragment of 1595 bp and 23 different haplotypes. The analyses showed a very ancient lineage divergence ~ 4.5 Myr and high genetic differentiation among localities (FST=0.932; p<0.01), suggesting a limited gene flow among geographical regions. The demographic analyzes and neutrality tests indicated that there is no sign of expansion and that populations have constant size (Tajima’s D = 0.521; p = 0.763 and Mismatch distribution = 0.009; p= 0.779). In the analysis of the evolutionary relationship between haplotypes (by median-joining network method), no relationship between lineage and geographical space was found, suggesting incomplete lineage sorting. The results corroborate and give evidence that populations of M. lemniscatus were distributed in a more continuous region in the past, and the current distribution of this species may be the result of the reduction and separation of the geographical scope of their distribution, rather than having itself been an expansion event. This may be the result of cycles expansion of SDF and retraction of the rainforests during the cool and dry phases of the Quaternary.Item Filogeografia e estrutura genética de uma árvore de floresta estacional neotropical Tabebuia roseoalba (RIDL.) Sandwith (Bignnoniaceae)(Universidade Federal de Goiás, 2014-09-29) Melo, Warita Alves de; Collevatti, Rosane Garcia; http://lattes.cnpq.br/9979596352166630Tabebuia roseoalba (RIDL.) Sandwith (Bignoniaceae) is widely distributed in Neotropical seasonally dry forests, occurring mainly from Northeast towards the Central West and Southeast Brazil, and also in Paraguay, Bolivia and Peru. The phylogeography of this species may help us to understand how historical events influenced its genetic diversity and in the current geographic distribution of seasonally dry forests. The results were based on the sequencing of three chloroplast intergenic spacers (psbA-trnH, trnC-ycf6 and trnStrnG2S) and the nuclear ribosomal region (nrDNA) (ITS1 + 5.8S + ITS2). We sampled 18 populations (235 individuals) in North, Central West and Southeast. The three chloroplast regions generated a fragment of 1,519 base pairs and 37 haplotypes. We found high haplotype diversity (h = 0.839) and low nucleotide diversity (π = 0.00610 SD = 0.00311) and were found. A fragment of 506 base pairs was generated for nrDNA and 14 haplotypes were identified. The haplotype diversity (h = 0.336) was lower than chloroplast diversity but nucleotide diversity (π = 0.01669 SD = 0.00857) was higher. Populations of Tabebuia rosealba are highly differentiated (FST = 0. 684; p = 0.001) with low gene flow (Nm < 1.0) among all population pairs. Our results also showed significant population reduction followed by expansion (Mismatch Distribution SSD = 0.20746; p = 0.0002, Tajima D = - 1.766; p = 0.008, Fs = - 23.702; p = 0.001), and the Extended Bayesian Skyline Plot (EBSP) also showed population reduction. Coalescent dated tree showed an ancient time to most recent ancestor (TMRCA) dated from ~4.9 Ma (CI 95% 1.9 Ma) in the Pliocene. Both the median-joining network and the coalescent tree showed evidences of incomplete lineage sorting. Our data show that the current pattern of diversity found so far is in consonance with a wide distribution of this species in the past, strongly suggesting that the climate changes of the Quaternary Period had strongly influenced the genetic diversity pattern and the geographical distribution of the species.