Mitochondrial DNA phylogeography of Brazilian populations of Drosophila buzzatii

Abstract

The Argentinean Chaco region has been considered the center of origin of Drosophila buzzatii in South America because it contains most of the chromosomal polymorphism detected in natural populations. Two hypotheses have been put forward to explain the distribution of D. buzzatii in Brazil, one proposing that it has only recently passively colonized Brazil via human dispersal and the other suggesting that D. buzzatii has actively migrated to Brazil some time ago. Data from chromosomal inversions support recent colonization, whereas data from allozymes and mtDNA variation indicate that D. buzzatii has been in Brazil longer, favoring an active dispersal hypothesis. In our present work we analyzed data on 56 South American flies, mostly from Brazil, sequenced for the 5' end of the mtDNA COI gene. The combined use of many neutrality tests and phylogeographic methods (e.g. nested clade analysis) indicated high gene flow throughout most of the range of D. buzzatii, although significant population structure was still detected. The high nucleotide diversity in the Northeast region of Brazil and the results from the nested clade analysis suggest that D. buzzatii has been in Brazil longer than proposed by the passive dispersal hypothesis. Our data indicate that D. buzzatii has been distributed throughout Brazil and Argentina since the Quaternary, though more data from different localities and markers need to be gathered to determine how the occupation of South America by D. buzzatii has occurred.

Genetic variability of Aedes aegypti in the Americas using a mitochondrial gene: evidence of multiple introductions

“…1) and the unimodal, relatively smooth and narrow-tailed mismatch distribution of pairwise differences, very similar to expected values (Fig. 3B), supports a hypothesis that Clade 1 experienced a recent demographic expansion (de Brito et al 2002, Slatkin & Hudson 1991. Groups 1-1 and 1-5 could be an introduction of US and/or Venezuelan haplotypes with a secondary introduction probably through Brazilian harbors, leading to the long distance movement pattern showed by the nested clade 2-1.…”

MtDNA variability in whitefly (Bemisia tabaci) populations in Brazil

“…According to the gene flow model restricted via isolation by distance, it is expected that the most recent haplotype tends to be the least frequent and least dispersed (Templeton et al, 1995;De Brito et al, 2002). However, since each haplotype had only one copy, the frequency criterion cannot be used; only the number of differences observed between them can be used as a criterion.…”

Filogenia do Complexo Drosophila Buzzatii (Grupo Repleta): Inferências de Análises Multilocus Mitocondriais e Nucleares.

“…Além da utilização dos genes mitocondriais para a elaboração de hipóteses filogenéticas para o compelexo D. buzzatii (Spicer, 1995, Durando et al 2000 e para o cluster D. buzzatii (Manfrin et al 2001), tais genes têm sido utilizados para o estabelecimento de hipóteses filogeográficas para as espécies desse cluster (de Brito et al 2002a;de Brito et al 2002b;Morales, 2005;Franco, 2009). …”

“…Entretanto, estudos biogeográficos recentes com D. buzzatii (de Brito et al 2002b;Santos, 2011) (Cann et al 1987;Templeton, 1998). Os dados do gene COI, portanto, sugerem uma presença mais ancestral da espécie D. buzzatti no nordeste brasileiro, hipótese reforçada pela existência de alelos aloenzimáticos exclusivos em suas populações .…”