DLS: David Gold (Caltech)
Date Time Location
November 15th, 2017 4:00pm-5:00pm
"Interpreting geochemical biomarkers in the light of genomics"

Biological compounds preserved in rocks can function as biomarkers, providing insight into long-extinct organisms. Because scientists understand many of the biological pathways necessary to synthesize biomarkers, the genetic and geochemical records can be used to inform each other, and improve our understanding of these “molecular fossils.” In this talk, I will focus on one class of biomarkers (the steranes) and consider what we do and don’t understand about these compounds in light of biological data. In some cases, molecular clock analyses have lined up well with the biomarker record, confirming our expectations, but in other cases the two lines of data are in conflict. When biomarkers are considered within a phylogenetic (evolutionary) framework, I suggest that there is a lot of uncertainty remaining in the interpretation of steranes. I will conclude by offering several areas of research that should help distinguish between current competing hypotheses about the biomarker record and the evolution of complex life.