Programa de Pós-graduação em Genética e Biologia Molecular
URI Permanente desta comunidade
Navegar
Navegando Programa de Pós-graduação em Genética e Biologia Molecular por Por Orientador "Collevatti, Rosane Garcia"
Agora exibindo 1 - 4 de 4
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 A história evolutiva de uma perereca Sul-Americana Scinax squalirostris (Lutz, 1925) (Anura, Hylidae): um resgate do passado e consequências futuras(Universidade Federal de Goiás, 2018-10-31) Jardim, Tatianne Piza Ferrari Abreu; Maciel, Natan Medeiros; http://lattes.cnpq.br/2116561844584292; Collevatti, Rosane Garcia; http://lattes.cnpq.br/9979596352166630; Maciel, Natan Medeiros; Silva, Daniela de Melo e; Lima, Natácia Evangelista de; Lima, Luciana Signorelli Faria; Machado, Iberê FarinaGeological events of the Neogene and the climatic fluctuations of the Quaternary played an important role in shaping the landscape and climate of South America therefore directly influencing the evolutionary history of the organisms of this area over the last million years. These changes led to the alternation between warm and humid, cold and dry periods. Such alternation dictated the dynamics of retraction and expansion of open and forest landscapes. Species associated to these environments evolved following this dynamic, which lead to alteration in genetic conformation, lineage differentiation and even speciation. As in the past, future changes inclimate can modify the landscape causing changes in the geographical distribution of species. In addition, predicted global warming may lead to a decline in genetic diversity as well as lead to extinction due to species' low ability to adapt to drastic and quick changes. In this thesis two regions of mitochondrial DNA (Cytb and 12S) and one nuclear (RAG-1) were used together with coalescing simulations, and ecological niche modelling to access the evolutionary history of a Scinax squalirostris (Lutz, 1925), a species associated to the South American grasslands. In the first chapter, we sought to understand how Neogene and Quaternary geological or climatic events, respectively, may have shaped the current disjunct distribution and the genetic diversity pattern of S. squalirostris. The populations of S. squalirostris were found to have high genetic diversity, with no sign of current gene flow, a high genetic differentiation, and a stable demographic history over time with scattered origin in southern Brazil. Coalescence events date from Pliocene-Pleistocene, with haplotype sharing among geographically distant populations, which indicates incomplete lineage sorting. The paleodistribution models suggests that S. squalirostris lineages were widely distributed during the last glacial maximum (LGM) but afterwards contracting and changing their area of occurrence. These results indicate that the current geographic distribution and genetic diversity of S. squalirostris is due to the contraction of an area widely distributed in the past, generated by the dynamics of retraction of grasslands in warmer periods due to the loss of areas suitable for their occurrence. In the second chapter, we tested the hypothesis that the current populations of S. squalirostris could represent distinct lineages with candidate species not previously described, due to the current disjunct distribution. Using molecular and morphometric data the formation of two groups was rescued. One of them consists in a candidate species to be described, which is a lineage restricted to the Central-West region of Brazil. The other one comprises of populations from the South and Southeast Brazil, Paraguay, Uruguay and Argentina. In the third chapter, ecological niche modelling, molecular techniques and simulations of genetic groups were used to verify how future climate changes could alter the genetic diversity and distribution of S. squalirostris. Through two climatic scenarios with different temperature changes to 2100 (scenario 4.5 RCP increases 1.8 ° C and stabilizes, and scenario 8.5 increases 3.7 ° C and continues to increase), ecological niche modelling analysis indicated a decrease of suitable areas in the Central-West and Southeast regions, with a displacement towards the South of Brazil entering the central region of Argentina towards more anthropized areas. Most of the Central West and Northern Southeast populations may be extinct due to the absence of climatic suitable areas for their occurrence and low genetic diversity. In addition, it was observed that Protections Areas (PAs) currently harbors a large part of the genetic diversity of S. squalirostris. Thus, PAs in areas that will be ideal for the occurrence of S. squalirostris will be able to maintain their high levels of genetic diversity, but with losses of genetic diversity in the Midwest and Southeast regions. This work indicates that future climate changes will negatively affect this species, since the appropriate areas for its occurrence will be reduced and displaced. The loss and changes in genetic clusters may lead to a possible loss of the evolutionary potential of S. squalirostris populations in responding to future climate changes, which could result in the extinction of some populations.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.Item Filogeografia e história demográfica de tabebuia serratifolia e tabebuia ochracea (bignoniaceae), duas espécies arbóreas neotropicais(Universidade Federal de Goiás, 2015-12-09) Vitorino, Luciana Cristina; Collevatti, Rosane Garcia; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4784443D2There is strong evidence that the Neotropical vegetation has been influenced by climate changes at the end of the Tertiary and Quaternary. The response of vegetation to the cold weather and dry these periods, consistent with the occurrence of the last glacial maximum, still remains in debate. It is suggested that the areas currently occupied by the Cerrado and seasonal forests (SDTFs) are remnants of a continuous vegetation that existed in the past. From the perspective of that species widely distributed in savannas and Brazilian SDTFs could help unravel the role of climate change Pleistocene on the current distribution pattern of genetic diversity in these vegetation types, we sampled 17 populations of Tabebuia serratifolia in SDTFs and 24 populations Tabebuia ochracea in savannas and sequenced intergenic non-coding regions of chloroplast (psbA-trnH, trnG-trnS e trnC-ycf6) as well as the nuclear region ITS (nrDNA). Later, we used coalescent analysis, Ecological Niche Modeling techniques (ENM) and simulations of demographic hypothesis for these species in an attempt to broaden the understanding of the changes undergone by neotropical landscape during the last ice age cycles. The sampled populations for both species showed high genetic diversity for both markers (hcpDNA = 0.8731 and hnrDNA = 0.7723 - T. serratifolia and hcpDNA = 0.927 and hnrDNA = 0.637 - T. ochracea), and large structure (Fst(cpDNA) = 0.528, P < 0.001 and Fst(ITS) = 0.742, P < 0.001 - T. serratifolia and Fst(cpDNA) = 0.742, P < 0.001 and Fst(ITS) = 0.544, P < 0.001 - T. ochracea). The coalescing analysis showed the time to the most recent common ancestor between haplotypes of the sampled populations, oldest to T. serratifolia (~ 3.4 Ma - 95% CI 1.9 - 6.8), which for T. ochracea (~ 1.9 Ma - 95% CI 0.1 - 2.3). The two species show standard recent population expansion and the niche modeling revealed for the T. serratifolia a higher potential distribution area during Holoceno medium while for T. ochracea the highest suitability area was predicted for maximum glacial last (LGM - 21ka), going in favor the hypothesis that the savannas and STDFs have submitted in the past, a wider distribution than currently known.