Genetic Distance and Evolutionary Relationships in the Drosophila obscura Group

Reevaluation of Phylogeny in the Drosophila obscura Species Group Based on Combined Analysis of Nucleotide Sequences

“…2A) gives high support for the traditional phylogeny within the pseudoobscura, obscura, and subobscura subgroups (Throckmorton, 1975;Lakovaara and Saura, 1982;Beckenbach et al, 1993). This analysis of the COII locus shows that a If the NJ or ML tree depicts a relationship different from that of the MP, the species (as Table 1) and species subgroup forming the clade are shown.…”

“…This microlabis-subobscura clade is nested within a larger Old World clade, which contains the remaining species placed in the obscura subgroup. Support for this hypothesis comes from biogeographic information (Throckmorton, 1975), previous morphological and molecular studies (Lakovaara and Saura, 1982;Cariou et al, 1988;Ruttkay et al, 1992), and cladistic analyses (Fig. 6 and data not shown).…”

“…1C). Finally, recent nucleotide sequence studies have shown that the obscura subgroup (sensu Lakovaara and Saura, 1982) can be further divided into the subobscura and obscura subgroups ( Fig. 1D; Barrio et al, 1994).…”

“…They concluded that, within the ''traditional'' obscura subgroup (sensu Sturtevant, 1942), there were two distinct lineages of Nearctic species and several lineages of Palearctic species. Research conducted in the past 25 years, including allozyme electrophoresis (reviewed in Lakovaara and Saura, 1982), mitochondrial restriction site analysis (Latorre et al, 1988;Gonzalez et al, 1990;Barrio et al, 1992), polytene chromosome phylogenies (Brehm et al, 1991), DNA-DNA hybridization (Goddard et al, 1990), and nucleotide sequences (Beckenbach et al, 1993;Barrio et al, 1994;Russo et al, 1995;Barrio and Ayala, 1997), has refined our view of evolution in the obscura group. In their review of the obscura group phylogeny, Lakovaara and Saura (1982) summarized these data and indicated that the obscura subgroup can be divided into two subgroups, obscura and pseudoobscura (Fig.…”

“…1B). Several phylogenetic analyses have shown that the pseudoobscura subgroup, which is distributed exclusively in the New World, is most closely related to species placed in the Nearctic affinis subgroup (e.g., Lakovaara and Saura, 1982;Barrio et al, 1992;Barrio and Ayala, 1997). The common ancestor of these species groups likely colonized the western Nearctic region prior to mid-Miocene times, approximately 20 million years ago (Throckmorton, 1975).…”