UV-induced cellular aggregation mediates intercellular chromosomal HGT marker exchange with high frequency, and UV-induced cultures display recombination rates that exceed those of uninduced cultures by as much as three orders of magnitude. "S. solfataricus" cells aggregate preferentially with other cells of their own species. Frols et al. and Ajon et al. suggested that UV-inducible DNA transfer is likely an important mechanism for providing increased repair of damaged DNA via homologous recombination. This process can be regarded as a simple form of sexual interaction.