The videos, shown with minimal information and often without sound or music, are meant to provide a sort of scientific cinéma vérité.
Image courtesy of Nipam Patel (University of California, Berkeley, CA).

The theory is proposed that the pyrimidines in extant nucleic acids are postenzymatic substitutes for their isoelectronic and isogeometric position 3-bonded purine analogs xanthine and isoguanine, which were sibling products in a preenzymatic de novo purine pathway.
