Origins of life: corroboration of common ancestry via statistics
Just as I wrote the last post, in fact a few days earlier, an article came out in Nature entitled “A formal test of the theory of universal common ancestry“, by DL Theobald. It uses a novel approach to asses the probability that all life shares a “universal common ancestry” (UCA). The authors compare sequences of ubiquitous and conserved proteins across the three domains of life, Bacteria, Archaea and Eukarya. They arrive at the conclusion that the probability of UCA is quantitatively overwhelming:
UCA is at least 10^2,860 times more probable than the closest competing hypothesis
The author notes that multiple origins of life may still be possible, but all current life extant (LAWKI) is likely of common origin. What’s new in this approach is the creative use of data to put a likelihood number on the various qualitative points made since Darwin’s assertion of UCA (and reiterated in the previous post).