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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Mapeamento físico cromossômico de elementos repetitivos em marsupiais Amazônicos

Silva, Carlos Eduardo Faresin e 26 August 2016 (has links)
Submitted by Gizele Lima (gizele.lima@inpa.gov.br) on 2017-02-14T14:19:32Z No. of bitstreams: 2 Tese_CEfS_versão final.pdf: 2066725 bytes, checksum: 99e5eaff3b19590a9f535bb0d1280004 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-02-14T14:19:32Z (GMT). No. of bitstreams: 2 Tese_CEfS_versão final.pdf: 2066725 bytes, checksum: 99e5eaff3b19590a9f535bb0d1280004 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-08-26 / Fundação de Amparo à Pesquisa do Estado do Amazonas - FAPEAM / Currently, marsupials are the second largest mammals living family. The groups evolutionary history is linked to the geological history of the continent and in South America, they are represented mainly by Didelphidae family. This family is the only present in the Amazon and in the rest of Brazil. Marsupial cytogenetic characterization shows a conservation of diploid numbers ranging from 10 to 32 chromosomes, and in didelphids are known karyotypes 14, 18 and 22 chromosomes. In this context, molecular cytogenetic allows for new inferences about the chromosomal evolution, supplying additional characters to analyze, for example, mapping repetitive regions of the genome. In this paper we map repetitive elements in species didelphids collected in 13 new locations in the Amazon in unexplored regions, seeking to understand evolutionary patterns of karyotypes. In all were analyzed 194 individuals of 16 species featured in conventional staining, band C, Ag-RON and FISH with probes DNAr18S, telomeric and transposable element LINE-1. We observed variation on the X chromosome, the distribution of heterochromatin and mapping sequences of 18S ribosomal DNA and telomeric sequences. The main variation found in the position of the centromere was the X chromosome of C. lanatus and Marmosa murina. Geographically, the different types of X, both species showed a segregation between eastern and western Brazil, with contact in the central Amazon. For species Marmosops spp. two patterns of X were evidenced by the C-band technique, but less obvious geographical distribution. The nucleolar organizer regions were confirmed by 18S rRNA gene probe in all species except the marking of the Y chromosome Monodelphis brevicaudata. The distribution of this marker showed only variable in Marmosa genre. Considering RON simple as a character plesiomorphic conclude that the species of the genus Didelphis and Marmosa evolved independently for multiple system. Marsupials are considered chromosomally conservative, however, given the current state of knowledge to this group, inter variations and intraspecific are observed and this is due to the expansion of the sample and the application of more accurate techniques, suggesting the presence of chromosomal rearrangements in evolution this animal group. Regarding the telomeric sequences, 11 species were analyzed and compared the presence of interstitial telomeric sequences (ITSs) with the distribution of the C band and found that STIs are coincident with heterochromatin blocks. Of the 11 species examined, only 5 had STIs, all within the centromeric heterochromatin region. The presence of STIs was constant on the X chromosome of Marmosa individuals and murine variable in the other species. We believe that the variable presence of STIs is a particular characteristic of each lineage. Our results support the inference that such sequences can not always be interpreted as a consequence of chromosomal rearrangement. Finally, we map the LINE-1 retroelement to five species of copies: Caluromys philander, Gracilinanus emiliae, Marmosa murina, Marmosa demerarae and Didelphis marsupialis. The markings are shown scattered all chromosomes, with no preference for specific chromosome regions, or even the X chromosome, as reported in the literature for other marsupials. The most informative variations were in the morphology of the X chromosome, which verified the existence of geographic patterns and are possibly related to different species, showing that chromosomal variation has relation to the diversification of species. Markers of repetitive sequences (18S, telomere and L1) showed variations possibly be related to more recent events of speciation. / Os marsupiais sulamericanos estão representados principalmente pela família Didelphidae considerada conservada cariotipicamente. No presente trabalho mapeamos elementos repetitivos em 194 indivíduos, representando 16 espécies de didelfídeos, coletadas em 13 localidades ainda não exploradas, do ponto de vista científico, na Amazônia, para verificar possíveis padrões de evolução cariotípica. Para isso foram utilizados métodos citogenéticos clássicos e moleculares. Variações no cromossomo X, na distribuição da heterocromatina e no mapeamento de sequências de DNA ribossomal 18S e sequências teloméricas foram registradas. A principal variação foi na posição do centrômero do cromossomo X de Caluromys lanatus e de Marmosa murina. Os diferentes tipos de cromossomos X, de ambas espécies, mostraram uma separação em termos geográficos entre leste e oeste do Brasil, com contato na Amazônia central. Para as espécies de Marmosops spp., dois padrões de X foram evidenciados pelo método de banda C, porém não foram separados geográficamente. As regiões organizadoras de nucléolo foram confirmadas pelas sondas de DNAr 18S em todas as espécies, exceto a marcação do cromossomo Y de Monodelphis brevicaudata. A distribuição desse marcador se mostrou variável apenas no gênero Marmosa. Considerando a RON simples como um caráter plesiomórfico sugerimos que as espécies do gênero Marmosa e Didelphis marsupialis evoluíram independentemente para o sistema múltiplo. Em relação às sequências teloméricas, 11 espécies foram analisadas e cinco apresentaram ITSs, todas dentro da região de heterocromatina centromérica. A presença de ITS foi constante no cromossomo X de indivíduos de Marmosa murina e variável nas demais espécies. Acreditamos que a presença variável das ITSs seja uma característica particular de cada linhagem. O retroelemento LINE-1 foi mapeado em exemplares de cinco espécies: Caluromys philander, Gracilinanus emiliae, Marmosa murina, Marmosa demerarae e Didelphis marsupialis. As marcações se mostraram dispersas por todos os cromossomos, não havendo preferência por regiões específicas do cromossomo, nem mesmo pelo cromossomo X. A variação do cromossomo X e os padrões de distribuição dos elementos repetitivos podem ser reflexo dos eventos de especiação ocorridos nos didelfídeos.

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