Asgard archaea fan tree (IMAGE) University of Texas at Austin Caption According to this latest study, all complex life forms (a.k.a. eukaryotes) trace their roots back to a common ancestor among a group of microbes called the Asgard archaea. Credit University of Texas at Austin Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.