PALEOGENOMICS AND PLATE TECTONICS: REVOLUTIONS IN THE EARTH AND BIOLOGICAL SCIENCES

Among planets in the Solar System Earth uniquely has a very active plate tectonic system and extensive life. Tectonic history before there was an understanding of the mechanisms of plate tectonics was a description of phenomena, where basins had gone down and mountains had gone up, all interpreted through geosyncline theory. Plate tectonics has provided the overarching mechanism to understand tectonic history. Similarly, documentation of the evolutionary history of life in deep time has shown new organisms evolving, radiations of these new organisms, and extinctions. The new field of paleogenomics aims to provide the fundamental evolutionary mechanisms for how new innovations appeared and populated the Earth. There are a variety of approaches that have been utilized in paleogenomics. One very successful approach has been the sequencing of genomes of relatively recently extinct organisms, such as Neanderthals. Another way is to track morphological innovations from the deep time fossil record which are produced by known genes or sets of genes in modern organisms, to date when these genes first evolved and/or interacted. Changes in these sets of genes and their interactions, or gene regulatory networks, are key drivers for evolutionary change. This developmental approach has great potential to understand at the genetic level many of the evolutionary innovations which have had significant impact on the history of life. For example, paleogenomic investigations of biomineralization genes for sponges and echinoderms have been very informative. Similarly, identification of the genes which allow scleractinian corals to turn formation of the mineralized skeleton on and off during periods of changing ocean chemistry will have great utility for understanding reef development. Paleogenomic studies of skeleton formation in vertebrates have also provided significant perspective on the evolutionary process. Other studies of great promise include paleogenomics of flowers in plants and feathers in dinosaurs. This new understanding will be Earth history with genes, and the identification of genes and gene regulatory networks involved in specific evolutionary innovations will be as important as it was for adding plate tectonic mechanisms to the understanding of tectonic history.