Morfologycal and cytogenetic study in two species of tortoises of the genus Chelonoidis (Testudines)

• Grant number: 09/04466-9
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2009
• End date: February 28, 2011
• Field of knowledge: Biological Sciences - Zoology - Morphology of Recent Groups
• Principal Investigator: Maria Tercília Vilela de Azeredo Oliveira
• Grantee: Tiago Lucena da Silva
• Host Institution: Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil

Abstract

The reptiles have reduced the number of species since the time that dominated the land until the present day. The turtles are poorly studied, mainly on its morphological and cytogenetic characterization. This project aims to establish the analysis of morphological characteristics effective for the differentiation of this species, and organize the karyotype and analyze the structure of chromosome of Chelonoidis carbonaria and Chelonoidis denticulata, representative species of land tortoises of two Brazilian biomes (Cerrado and Amazonia). The chromosomal studies will be performed by classical and molecular cytogenetic techniques. The animals will be collected at the farm "Reginaldo Uvo Leone" (IBAMA registration no. 167525) located in Tabapuã - SP (S20 º 59 '47.4 ", W 49 07' 16.6 "). This project belongs to a broader study, authorized by IBAMA has been obtained on 24/03/2008 and is under registration with IBAMA no. 2,448,369, the license is valid until 24/03/2009 where, then, should be revalidate .I'll be carried out measurements of external morphology, and blood collection for assembly of the cultures of lymphocytes. The blood samples of both species will be collected by the margin-costal vein. To achieve the cariograma, the blood is inoculated in the culture of tissues, where lymphocytes are stimulated by the addition of fitohemaglutina. After 71 hours, the colquicina will be added to inhibit the formation of the spindle fibers, causing the cells remain in metaphase. Is hipotonização carried out to facilitate the spreading of chromosomes on slides, and then made the process of fixation. The conventional Giemsa staining is used for visualization and classification of chromosomes into groups according to their size and position of centromere, will be used the technique of chromosome banding G and C and impregnation by silver ions (Ag-NOR staining). Cytogenetic molecular techniques will be used for marking of specific sequences in the chromosomes (chromosomal Hybridization). The acquisition of these data should allow the recognition of possible hybrid individuals, showing morphological characteristics intermediate between the two species of the study and according to the literature this is a sign of ecological imbalance, because due to the destruction of the cerrado, a kind Chelonoidis Carbonara is broadening its ecological niche, closer to areas of rainforest , logging in sympatry with its sister species Chelonoidis denticulata, thus generating individuals hybrids. This knowledge should contribute to the knowledge of the biology of turtles, working for future genetic studies and development of these animals and, especially, generating data that contribute to preservation of this important group. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

SILVA, Tiago Lucena da. Estudo morfológico e citogenético em duas espécies de jabutis do gênero Chelonnoidis (FITZIGER, 1835)(Testudnines). 2011. Master's Dissertation - Universidade Estadual Paulista (Unesp). Instituto de Biociências Letras e Ciências Exatas. São José do Rio Preto São José do Rio Preto.