Recombination

The notion of “recombination” covers a range of phenomena associated with reshuffling of the parental genetic material into new combinations. Systematic studies of recombination initiated by Thomas Morgan in the early 1910s have developed during the 20th century into one of the most fruitful branches of genetics and evolutionary biology, and keep on flourishing with the progress of analytical methods. In sexually reproducing organisms, recombination is one of the major sources of genetic variation. Being sensitive to both genomic and ecological factors, it ensures a fine-tuned balance between stability and flexibility of genetic organization, enabling the adaptation of populations to their current environments and, simultaneously, the adaptability in face of potential challenges. Bridging between heredity and environment, recombination is both a factor of and a subject to evolution, which feeds up the ever-increasing interest in this process within the biodiversity paradigm. Analysis of natural populations, laboratory experiments, and theoretical modeling shed new light on the short- and long-term effects of recombination, as well as on its interplay with other evolutionary factors, such as selection, mutation, transposable elements (TEs), genetic drift, and gene flow. This, in turn, contributes to a better understanding of how recombination itself could have originated, evolved, and maintained. Yet, numerous important aspects of recombination evolution remain obscure. This is especially true for the relatively new question of why recombination possesses a certain set of rather universal features (crossover interference, ecological plasticity, fitness dependence, etc.), which started to fascinate researchers much later than the classic question of why recombination exists.