RNA-First and Integrated Origin Models
The Explanation
A major family of origin-of-life models gives RNA an early and important role because RNA can both carry sequence information and perform catalytic functions.
The RNA World hypothesis proposes that RNA, or molecules with similar properties, played a central role before the modern division of labor among DNA, RNA, and proteins developed.
Other models place greater emphasis upon metabolism, membranes, peptides, mineral surfaces, or networks of mutually supporting chemical reactions. Increasingly, researchers investigate ways in which several of these processes might have developed together rather than requiring one component to appear fully formed before the others.
These models are scientifically useful because they propose mechanisms that can be investigated experimentally. They have produced substantial progress in understanding individual steps.
They do not yet provide a single experimentally demonstrated history of the origin of life. Questions remain about replication, heredity, metabolism, compartmentalization, biological information, the genetic code, and the integration of these features into an evolvable system.