Chromosomal phylogeny of the Drosophila fasciola species subgroup revisited (Diptera, Drosophilidae)

Abstract

The analysis of polytene chromosomes in 26 strains of seven species in the Drosophila fasciola subgroup, from several locations in Brazil, in addition to strains of two species belonging to the Drosophila mulleri subgroup (D. aldrichi and D. mulleri), enabled us to determine that the 3c inversion found in the latter species differ in one of its break points from that present in the species of the fasciola subgroup. Therefore, a change in the mulleri complex denomination from inversion 3c to inversion 3u is proposed. Accordingly, the fasciola subgroup is no longer a lesser phylogenetic part within the mulleri subgroup. Rather, it is directly related to the likely ancestor of the repleta group, called Primitive I. This information removes the main obstacle to considering the Drosophila fasciola subgroup as an ancestral group within the Drosophila repleta species group, according to the hypothesis of Throckmorton. Our data also support the conclusion that D. onca and D. carolinae are closely related species based on one new inversion in chromosome 4 (4f 2 ), in both species. D. fascioloides and D. ellisoni also form a pair of sister species based on the presence of fusions of chromosomes 2-4 and 3-5. D. rosinae is related only to the likely ancestor of the fasciola subgroup, where the 3c inversion was fixed.

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

“…The phylogenies did not define all the interspecific relationships in the fasciola subgroup. In both of the hypotheses described above D. ellisoni and D. fascioloides appear as sister species (Figure 3), which is in agreement with the cytogenetic data produced by Diniz and Sene (2004) (Figure 1). In the differentially weighted phylogeny ( Figure 3B) (Vilela, 1983) but which shows no relationship between D. carolinae and D. senei.…”

“…The existence of the 3c inversion in both the mulleri complex of the mulleri subgroup and in species of the fasciola subgroup supports the hypothesis of a common ancestry, with the fasciola subgroup stemming from the mulleri subgroup (Wasserman, 1982(Wasserman, , 1992. However, Diniz and Sene (2004) recently showed that the fixed 3c inversion of the mulleri complex is not the same as the one observed in the fasciola subgroup, suggesting that the name of the inversion in the mulleri complex should be changed from 3c to 3u. This suggests that the ancestral chromosomal composition of the fasciola subgroup (Primitive VII) derived from the Primitive I, the ancestral sequence of the repleta group (Wasserman, 1960;Wasserman, 1992) (Figure 1).…”

“…Most of the studies regarding the establishment of a phylogeny for the fasciola subgroup have been cytological (Wasserman, 1962(Wasserman, , 1982(Wasserman, , 1992Kuhn et al, 1995;Diniz and Sene, 2004). The existence of the 3c inversion in both the mulleri complex of the mulleri subgroup and in species of the fasciola subgroup supports the hypothesis of a common ancestry, with the fasciola subgroup stemming from the mulleri subgroup (Wasserman, 1982(Wasserman, , 1992.…”

“…This suggests that the ancestral chromosomal composition of the fasciola subgroup (Primitive VII) derived from the Primitive I, the ancestral sequence of the repleta group (Wasserman, 1960;Wasserman, 1992) (Figure 1). Furthermore, Diniz and Sene (2004) proposed two new species complexes within the fasciola subgroup, the fascioloides complex made up of D. ellisoni and D. fascioloides that share the 2d 3 inversion, two chromosomal centric fusions (2-4F and 3-5F) and karyotype similarity regarding the X chromosomes (Kuhn et al, 1995) (Figure 1) and the onca complex, containing D. carolinae and D. onca which both share the 4f 2 inversion (Figure 1). Previously, chromosomal data had suggested two complexes, the pictilis complex (D. pictilis and D. pictura) and the moju complex (D. moju, D. mojuoides and D. paraguttata) (Wasserman, 1992) (Figure 1).…”

“…To help resolve this we analyzed partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene of nine species of the fasciola subgroup (Table 1) with the aim of trying to understand the origin and evolution of the this subgroup and consequently adding to the current knowledge on the repleta group. Figure 1 -Diagram illustrating the phylogenetic relationships among some species within the fasciola subgroup and between the subgroups in the repleta group (modified from Wasserman, 1992 andSene, 2004).…”