Current Projects

 If you could replay the tape of evolution, would you get the same outcomes? One approach to this question is to examine whether an ancient developmental program was repeatedly adapted in the same way to the same novel environment. For example, the aquatic ancestors of myriapods (millipedes, centipedes, etc) and insects (beetles, etc) began diverging 540 million years ago, and yet when myriapods and then later insects independently colonized land, they each separately evolved respiratory systems that are astonishingly similar: a spiracle (small, circular opening associated with each leg) that leads to an internally branching network of tracheae (thin tubes). Insect and myriapod traits, including tracheae, are so similar, in fact, that their close phylogenetic relationship was unquestioned for over a century. Only in the last decade has molecular evidence revealed that myriapods and insects are surprisingly not closely related at all: myriapods and crustaceans diverged first, and then much later insects evolved from crustaceans. Thus, the molecular phylogenetic data show that tracheae must have evolved independently in myriapods and insects, meaning that their incredible similarities must be due to convergent evolution brought about by terrestrialization. However, in yet another unexpected turn, my research suggests that, while these are not homologous as tracheae, myriapods and insects appear to have separately internalized the same external aquatic gill to make internally-branching tracheae. 

In contrast to all other arthropods - insects (beetles, etc.), crustaceans (shrimps, etc.), and chelicerates (spiders, etc.) - the myriapods (millipedes, centipedes, etc.) surprisingly do not have a single, lab-tractable model. Despite the lack of a suitable model, there is keen interest in myriapod segmentation and body patterning, neural patterning, bespoke reproductive structures, cyanide-based defensive glands, and paleontological and evolutionary origins. My own research suggests that myriapod and insect tracheae evolved via the independent internalization of the same ancestral gill. I am therefore developing the garden millipede Oxidus gracilis, which breeds prolifically and year-round in lab conditions, reaches sexual maturity in four months, and lays clutches of ~200 embryos that hatch in 10 days.