Global Research Team including Dr. Mark Martindale, Dr. Joseph Ryan and Doctoral Student David Simmons Publish in Nature
Whitney Laboratory director Dr. Mark Q. Martindale, with Whitney faculty Dr. Joseph Ryan and Biology Doctoral Student David Simmons contributed to the research published in Nature this week, looking at which molecular pathways lead to different outcomes during evolution in a variety of animals. This work is important because for the first time it uses a uniform, forward molecular approach (Cel-Seq) and novel computational tools to gain insight into how the process of development interprets genomic changes over evolutionary time to create novel adult body plans. This proof of principle approach was successful due to the wide taxonomic range of animals examined, and the expertise of researchers from around the globe.
Researchers in the past had noticed, in both body form and molecularly, that within a given taxon, vertebrates for example, the early stages and the later stages of development could be quite different from one another (compare a fish to a giraffe), but the middle stages of development always looked quite similar. This convergence onto a similar form was thought to be a bottleneck or “constraint” on how much the adult body could change.
This global study participated in by Martindale, Ryan and Simmons, essentially took the flip side of this idea. They and their colleagues from Israel, Germany, and Australia compared many different kinds of animals and looked to see where the differences in gene expression occurred. In contrast to the within taxon comparisons, the between taxon sampling found that the same middle portion of development had the greatest amount of differences (not the most similar). Martindale noted, “This now gives us a target time in development to focus studies in order to understand the molecular basis for the evolution of different kinds of animals.” It also might identify core molecular pathways that operate during the middle stages of development that will unite all organisms within a particular group and distinguish them from all others, according to Martindale.
It provides a framework that needs to be tested in even greater detail with a larger range of different kinds of organisms and the UF researchers note that exciting details will emerge and concepts identified will continue to be refined.