Microsatellite markers in the investigation of Drosophila mediopunctata genome: development and genetic linkage map construction

Author(s)

Prianda Rios Laborda

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2011-05-25

Examining board members

Anete Pereira de Souza; Sérgio Furtado dos Reis; Maria Imaculada Zucchi; Sergio Russo Matioli; Evandro Marsola de Moraes

• Advisor: Anete Pereira de Souza

Abstract

Drosophila mediopunctata, a non-cosmopolitan fly of Neotropical distribution that belongs to the tripunctata group of the Drosophila subgenus, was chosen by some Brazilian researchers as a model in evolutionary studies. Several approaches, such as the analysis of natural variation and the influence of chromosome inversions in population dynamics, are traditionally used. Nevertheless, molecular markers, which would enhance the investigation of the genetic bases of the already known phenomena, are still not available for the species. Microsatellites are celebrated molecular markers and the chosen tool for the exploration of various organisms due to their ease of use. Nonetheless, their application in species whose genomes have not yet been sequenced requires a prior development phase. This study intended to develop, characterize and map microsatellites for the species D. mediopunctata so that initiatives concerning morphological variation, identification of genomic regions linked to interesting phenotypes, population genetics, etc can be carried out in the light of molecular data. A repetitive DNA-enriched library was constructed and approximately 2000 clones were sequenced. Six hundred microsatellites were identified and 134 loci were developed. The loci are small in length, with reduced number of motif repetitions, and are mainly composed of AC/GT dinucleotides. The use of D. mediopunctata microsatellites for heterologous amplification in other thirty Drosophila species was done with a 50% success ratio. In addition, a clustering analysis carried out with binary data obtained from the tripunctata species recovered already known phylogenetic relationships. A linkage map was constructed with recombination data of 49 markers and is 450 cM in length. The five major species chromosomes were identified on the basis of comparisons with the D. melanogaster genome and the Müller elements. This strategy also confirmed the great synteny predicted for the genus Drosophila. It was not observed agreement in loci order between both species. A genomic region associated to the number of abdominal spots was mapped to the chromosome II of D. mediopunctata (AU)