Paraphyly in Drosophila
Many biology students have hands-on experience working with Drosophila melanogaster. This little fly is one of the major workhorses of genetics. It may not be for long. That’s not to say people will stop working with the fly, but the fly may no longer be named “Drosophila melanogaster“. That’s because the Drosophila genus is paraphyletic and should be split into multiple genera. Oh, and D. melanogaster doesn’t hold the rights to the name Drosophila. Those rights belong to D. funebris, the first species named in the Drosophila genus. (Christopher Taylor at the Catalogue of Organisms has more.)
So, if D. melanogaster loses the rights to the genus name “Drosophila”, what will it be named? Well, the Drosophila genus can be divided into two subgenera. One of those subgenera is also named “Drosophila”. The other subgenus, Sophophora, contains D. melanogaster, amongst many other species. Therefore, D. melanogaster should be renamed “Sophophora melanogaster if the genus were split into multiple genera.
Here’s a phylogeny of the subset of the Drosophila with completely sequenced genomes:
Notice D. melanogaster amongst the Sophophoran species. Only this tree is extremely stripped down, omitting all the genera nested within the Drosophila genus. This is a much better tree:
Notice the four other genera nested within the Sophophora side of the phylogeny: Chymomyza, Scaptodrosophila, Zaprionus, and Dorsilopha. The last one in that list was named for the sake of being confused with Drosophila. And the Drosophila subgenus is intermingled with three other genera: Siphlodora, Engiscaptomyza, and Scaptomyza. It’s all one big mess.
So, will Drosophila melanogaster be ranamed Sophophora melanogaster? I doubt it. It’s up to taxonomists, and they never get anything done. This basically comes down to taxonomic precedence versus changing the name of one of the best known species. Neither will win, and we’re gonna be left with a paraphyletic taxon. Once again, taxonomy is meaningless.
Markow TA and O’Grady PM. 2005. Evolutionary genetics of reproductive behavior in Drosophila Annu Rev Genet 39: 263-291 doi:10.1146/annurev.genet.39.073003.112454