Why not just admit it? Read this and see what you think:
“We built a time series of networks that describe how domains have accumulated and how proteins have rearranged their domains through evolution. This is the first time such a network of ‘domain organization’ has been studied as an evolutionary chronology,” Fayez Aziz says. “Our survey revealed there is a vast evolving network describing how domains combine with each other in proteins.”
Each link of the network represents a moment when a particular domain was recruited into a protein, typically to perform a new function.
“This fact alone strongly suggests domain recruitment is a powerful force in nature,” Fayez Aziz says. The chronology also revealed which domains contributed important protein functions. For example, the researchers were able to trace the origins of domains responsible for environmental sensing as well as secondary metabolites, or toxins used in bacterial and plant defenses.
The analysis showed domains started to combine early in protein evolution, but there were also periods of explosive network growth. For example, the researchers describe a “big bang” of domain combinations 1.5 billion years ago, coinciding with the rise of multicellular organisms and eukaryotes, organisms with membrane-bound nuclei that include humans.
The existence of biological big bangs is not new. Caetano-Anollés’ team previously reported the massive and early origin of metabolism, and they recently found it again when tracking the history of metabolic networks.
The historical record of a big bang describing the evolutionary patchwork of proteins provides new tools to understand protein makeup.
University of Illinois College of Agricultural, Consumer and Environmental Sciences, “Protein ‘big bang’ reveals molecular makeup for medicine and bioengineering” at ScienceDaily (June 30, 2021) The paper is open access.
In short, it all sort of happens at once, which suggests an intelligent origin.