Eukaryotic Life (IMAGE) Arizona State University Caption The graphic shows a tree of life for complex forms known as Eukaryotes, that arose mysteriously around 1.2-2 billions years ago from a progenitor known as LECA (for Last Eukaryote Common Ancestor.) Jeremy Wideman and his colleagues used a new method to sequence mitochondrial DNA for around 100 species of flagellates--tiny aquatic organisms that populate many branches of the tree. These are seen on the graphic as red dots marking the particular lineages these flagellates belong to. Credit Graphic by Shireen Dooling Usage Restrictions None License Licensed 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.