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| Author(s): |
Cíntia Pelegrineti Targueta
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2009-02-16 |
| Examining board members: |
Luciana Bolsoni Lourenço;
Ana Paulsa Zampieri Silva de Pietri;
João Miguel de Barros
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| Advisor: | Luciana Bolsoni Lourenço |
| Abstract | |
The frog Engystomops petersi is widely distributed in the Amazon basin. Genetic divergence and speciation mechanisms of E. petersi populations have been inferred mainly from mitochondria DNA (mtDNA) and microsatellite polymorphisms, male advertisement call and sexual selection. In spite of the significant progress resulting from these studies, many cytogenetic, taxonomic and evolutionary aspects of E. petersi populations remain unclear. In the present study, cytogenetic analysis and nucleotide divergence in mtDNA and in the rhodopsin nuclear gene of E. petersi populations are described in an attempt to contribute to the understanding of this anuran. High cytogenetic variation distinguished karyotypic patterns, which included two populations with no prezygotic isolation. The Puyo and Acre populations showed heteromorphic sexual chromosomes (XX/XY), which were not identified in the other Equatorial populations. Since all the Equatorial populations were placed in a clade separated from the Acre populations, we hypothesize that the sex chromosomes X and Y is a plesiomorphic condition in this group. The results from mtDNA found here were very similar to those found in previous studies. In the rhodopsine nucleotide sequences, 6 SNPs (Single Nucleotide Polymorphism) were identified and various specimens were heterozygous for these nucleotide sites. The karyotypic and molecular data presented herein, in conjunction with previously reported data, corroborate the hypothesis that Engystomops petersi is a complex of distinct species and suggested hybridization and introgression events between populations. Moreover, tha data indicated that karyotypic evolution patterns may have played a substantial role in the Engystomops speciation. (AU) | |