Edge-effects dominate copying thermodynamics for finite-length molecular oligomers

Living systems produce copies of information-carrying molecules such as DNA by assembling monomer units into finite-length oligomer (short polymer) copies. We explore the role initiation and termination copy process in thermodynamics copying. By splitting free-energy change formation informational chemical terms, we show that accuracy plays no direct overall thermodynamics. Instead, it is thermodynamically costly to outputs are more similar oligomers environment than sequences obtained randomly sampling monomers. Copy can be neutral, or even favoured, depending on surroundings. Oligomer copying mechanisms thus function information engines interconvert information-based free energy. Hard thermodynamic constraints derived for infinite-length polymers instead manifest kinetic barriers experienced while template-attached. These easily surmounted shorter oligomers.