First Large-Scale Formal Quantitative Test Confirms Darwin’s Theory of Universal Common Ancestry

Science Daily: First Large-Scale Formal Quantitative Test Confirms Darwin's Theory of Universal Common Ancestry

ScienceDaily (May 17, 2010) — More than 150 years ago, Darwin proposed the theory of universal common ancestry (UCA), linking all forms of life by a shared genetic heritage from single-celled microorganisms to humans. Until now, the theory that makes ladybugs, oak trees, champagne yeast and humans distant relatives has remained beyond the scope of a formal test. Now, a Brandeis biochemist reports in Nature the results of the first large scale, quantitative test of the famous theory that underpins modern evolutionary biology. …

… Harnessing powerful computational tools and applying Bayesian statistics, Theobald found that the evidence overwhelmingly supports UCA, regardless of horizontal gene transfer or multiple origins of life. Theobald said UCA is millions of times more probable than any theory of multiple independent ancestries.

"There have been major advances in biology over the last decade, with our ability to test Darwin's theory in a way never before possible," said Theobald. "The number of genetic sequences of individual organisms doubles every three years, and our computational power is much stronger now than it was even a few years ago."

While other scientists have previously examined common ancestry more narrowly, for example, among only vertebrates, Theobald is the first to formally test Darwin's theory across all three domains of life. The three domains include diverse life forms such as the Eukarya (organisms, including humans, yeast, and plants, whose cells have a DNA-containing nucleus) as well as Bacteria and Archaea (two distinct groups of unicellular microorganisms whose DNA floats around in the cell instead of in a nucleus). …