Category: Research Blog (Page 2 of 7)
A few months ago, we had a little seat-of-the-pants discussion of the (macro)evolution of CNS and sensory systems in arthropods. If you want to follow up on that, here is a little review:
As many in our lab know, identifying homologous/orthologous genes in sister species is tedious process that even with decades of research, still generates vast uncertainty, which in turn, confounds downstream analyses (and is a pain to be honest).
Here are two recent papers that try to address the issue:
Another review in the last issue of NRG. Mainly human/primate work.
“Focusing on work in primates, the authors discuss the evolution of gene expression, ways of exploring mechanisms that underlie expression changes and complementary work in model organisms on the functional effects of expression changes.”
A useful review in NRG. Includes an overview of different bioinformatic and experimental approaches, and a list of useful software and websites.
Here is a new paper from the Yamamoto lab looking at the function of fru in individual brain neurons. This is is clearest evidence to date that FruM controls sex-specific differentiation on individual neurons through a transcription-dependent mechanisms. Another interesting possibility emerging from this paper is that the male- and female-specific differentiation programs are “pre-wired” into the neurons, and that FruM is needed to flip the switch between these programs but not to specify either. This seems remarkably similar to the role of Dsx in the gonad and external genitalia. Check it out.
In flies, sexually dimorphic behavior is coordinated in part by a dedicated neural circuitry established by Fruitless (Fru). A handful of receptors, such as GRs and ORs, have been shown to interact with specific pheromones and hydrocarbons and are essential for certain well-known behavioral repertoires in Drosophila. This paper shows that a pair of pickpocket (ppk) family sodium channels also play essential roles in promoting courtship behavior. Critically, its still not clear if this ion channel interacts directly with chemical cues from conspecifics, or if it plays a role in some other signal transduction pathway. It will be interesting to see what closely related paralogues of ppk might exist in drsosophilid taxa with distinct bristle morphologies, and or behavioral phenotypes.
Understanding how the genetic mechanisms that underlie sexually dimorphic traits evolve is a major focus of Kopp lab, but what are the macroevolutionary consequences of dimorphism? Theory suggests that dimorphic taxa ought to speciate more often than their monomorphic sisters, but this prediction has been difficult to test. Using comparative phylogenetic methods, this article finds support for an increased rate of speciation amongst dimorphic bird taxa. It is interesting to consider how macroevolutionary trends like species selection might be predicated on the activities of deeply conserved genetic modules like Dsx/Scr. Does anyone know if DMRT genes like Dsx are involved in specifying pigmentation pathways in verts?