Fly Tyrosine Kinase & PTP lists
Figure 1. Overview of relationships among major species groups and picture wing subgroups.
Schematic based on chromosomal inversions, DNA sequence data, and morphology. Arrow indicates the proposed single introduction of Drosophila to an island west of Kauai. Blue backgrounds, picture wing subgroups; green backgrounds, modified mouthparts, modified tarsus, and antopocerus groups; pink background, haleakalae/fungus feeder group. Lines schematically indicate consensus phylogenetic relationships. Examples of increasing pattern complexity in the adiastola and grimshawi subgroups are shown. See Figs. 2–7 of Edwards et al. 2007 for species names. Hawaii map courtesy of geology.com and mapresources.com.
The endemic Hawaiian Drosophila provide a spectacular example of adaptive radiation: ~1000 diverse species arose from what is believed to have been a single introduction of a continental Drosophila species to the Hawaiian Island Chain. The current Hawaiian Islands had not yet formed when Drosophila colonized the Chain about 26 million years ago. The older islands that were initially colonized have since eroded and subsided to sea level. Thus all the current Hawaiian species are the result of repeated rounds of "island hopping", the colonization of newly formed islands as they arose and became habitable. The species' habitats are also repeatedly fragmented by lava flows on each young island (this can be currently witnessed on the Big Island). These successive population bottlenecks and fragmentation events have promoted the evolution of hundreds of species.
Drosophila occurs worldwide, but Hawaii is home to the largest and most ornate flies in the genus. The best studied species are the "picture wing" group, known for their intricately patterned wings and complex behaviors. We have collected and mounted the wings from over 70 species of Hawaiian flies, and present this collection in Edwards et al. 2007 (open access). The original photos are going to available at FlyBase (we don't have the specific links yet). Below are two figures from our paper.
The picture wing fly D. grimshawi was included in the recent 12 Drosophila Genomes sequencing project, and the grimshawi genome is available here. We have mapped numerous genes on the chromosomes of the picture wing flies, and this mapping project has helped to comfirm the grimshawi sequence assembly (in prep). We are performing small scale EST sequencing from another picture wing fly, D. silvestris, and aliquots of the silvestris cDNA library are now available.
The picture wing flies provide a superb evolutionary model system, and one of the most valuable features of this system is the chromosome inversion-based lineage tree determined by Hampton Carson, in a landmark series of papers. See Carson's tree here.
The evolution of the Hawaiian flies is strongly influenced by sexual selection; natural selection alone cannot account for the ornate, male specific ornamentation found on many species. Ken Kaneshiro's work on sexual selection theory, rooted in his studies of the Hawaiian Drosophila, has been extremely influential in evolutionary biology.
WIth the grimshawi genome now available, the Hawaiian flies are poised to make new contributions to molecular evolutionary biology, as model systems for the evolution of pattern complexity, body size, life history traits, sexual behavior, and more.
Figure 2. The adiastola and primaeva/attigua subgroups of picture wing species.
D. adiastola, cilifera, clavisetae, hamifera, setosimentum, spectabilis, and truncipenna are shown as sexually dimorphic pairs, ornata and primaeva/attigua as single examples. In all figures, anterior is up and proximal is to the left. Inset, chromosome inversion-based lineage for the species shown. See Edwards et al. 2007 for the other picture wings and representative non-picture wing species, as well as information on the development of wing pigment patterns.
Left, modified mouthparts group. RIght, D. tanythrix from the antopocerus group. Note the feathered aristae.
The sister species D. silvestris and heteroneura. D. heteroneura exhibits a remarkable, male specific hammerhead phenotype.
D. grimshawi, the picture wing species that was sequenced.
Some of the secondary sexual characters seen in Hawaiian flies resemble known mutations described in D. melanogaster. D. inciliata could be mistaken for a neurogenic mutant.
Some of the Hawaiian Drosophila are rather large.
