Phylogenetic relationships in the Drosophila fasciola species subgroup (Diptera, Drosophilidae) inferred from partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene

The repleta group is one of the largest and most complex species groups in the genus Drosophila, representing an important biological model for the elaboration of evolutionary and biogeographical hypotheses on the American Continent. It is divided into six subgroups, of which the fasciola subgroup is the only one with most of its species found in the humid forests of Central and South America. With the aim of understanding the origin and evolution of the fasciola subgroup, and consequently adding information about the repleta group, we analyzed partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene of nine Drosophila species (D. carolinae, D. coroica, D. ellisoni, D. fascioloides, D. ivai, D. moju, D. onca, D. rosinae and D. senei). The phylogenetic hypotheses obtained neither defined the relationships between the subgroups of the repleta group nor defined all the interspecific relationships in the fasciola subgroup. We found that the species D. carolinae, D. coroica, D. onca, D. rosinae and D. senei comprised a clade in which D. carolinae, D. onca and D. senei appeared together at a polytomy while D. fascioloides and D. ellisoni comprised another clade with a high bootstrap value.

Detection of genetic variabiltiy in non - human isolates of fasciola hepatica and Fasciola gigantica by the RAPD - PCR Technique

The present study showed the molecular characterization of Fasciola gigantica and F. hepatica isolates collected from cows and sheep, using the random amplified polymorphic DNA fragments-polymerase chain reaction [RAPDs-PCR] technique. Optimal standardization of amplification conditions and thermocyclation were made, using genetic markers. The methodology used compared the genetic patterns of the two species [interspecies] and inside each species [intra-species] between cow and sheep and the amplification fragments were between 135 and 741 base pairs of marker. The results showed genetic variations [polymorphisms] of Fasciola gigantica and F. hepatica with amplification fragment based on a 500-400 base pair [bp]. Inside each species, there were genetic variations in bovine and ovine and the amplification fragments were between 600 and 400 base pairs [bp]

Comparative morphometry, morphology of egg and adult surface topography under light and scanning electron microscopies, and metaphase karyotype among three size-races of Fasciola gigantica in Thailand.

Comparative morphometry of eggs and adults under light microscope, and morphology of adults under scanning electron microscope (SEM) were undertaken in the three size-races (< 25 mm, 25-35 mm, > 35 mm) of Fasciola gigantica (Thailand strain). Morphometric examination revealed intraspecific variation with respects to the dimensions of eggs and adults, whereas surface topography of the three size-race adults under SEM was morphologically similar. The observations on mitotic metaphase chromosomes of spermatogonial cells from testes of the three size-races revealed 2n=20 (diploid type), and no karyotypic difference was observed among them. The meiotic metaphase chromosome was 10 bivalents in primary spermatocyte in diplotene to diakinesis, and many mature spermatozoa were seen in the testicular preparations.