The physical chemical steps leading to life on Earth took place at a time when endogenous water/rock interactions were strongly influenced by exogenous processes such as impact bombardments. At present, there is no direct measure of the influx of extraterrestrial matter in the epoch of late accretion approximately 4.48-4.0 Ga. Nevertheless, it is within that time span that life emerged on...
On the surface of the Earth, DNA oligonucleotides have been exposed to UV-irradiation since very early stages of evolution [1]. The role of UV-light is ambivalent: As it can cause damage, it imposes a selection pressure on oligonucleotides but it can also repair photolesions in a photolyase-like mechanism via charge transfer from adjacent bases [2]. Both processes strongly depend on the...
