Research Project T. Stadler

The existence of a universal common ancestor (UCA) to all known life on Earth is a fundamental assumption in evolutionary biology and at the basis of our understanding of how life evolved into the main lineages that we still observe today, namely, Bacteria, Archea, and Eukarya. The UCA is core to the idea of a tree of life, whereby a single lineage gave rise through speciation to the millions of lineages that populate our planet today. While the hypothesis of a UCA is compatible with the existence of a few universally shared genes, horizontal gene transfer and four billion years of evolution make it difficult to formally test it against alternative theories.

In this project, we challenge the idea that the existence of a UCA is supported by definitive evidence and develop new models to test the plausibility of an alternative hypothesis, which we term Multiple Ancestry of Present Life on Earth (MAPLE). We will use simulations, probabilistic approaches, and machine learning to evaluate the identifiability and empirical evidence for alternative scenarios around the origin and earliest development of life on Earth.