[Function of crossing-over].
The literature data are considered concerning the significance of genetic recombination and crossing over. An obvious result of recombination is production of the genotypically diverse offspring, but the main role of recombination consists of combining the genes from diverging subspecies and races, thus maintaining a rather wide ecological potential of a species. This effect of recombination substantiates the tendency for increasing complexity of organic forms in progressive evolution. Accordingly, evolution is considered as a chain of recombinational "syntheses". The literature data treating crossing over as a mechanism of DNA repair are discussed. This function of crossing over is interpreted, based on a notion implying, from the composition of genetic code, that a crystalline associate composed of bases as free molecules precedes the appearance of DNA in evolution. The stability of the crystalline associate of bases was due to "balanced" distribution of bases for their electrochemical properties. The degeneracy of genetic code seems to provide possibility of construction of the electrostatically "balanced" base sequences in highly expressed bacterial genes. Crossing over possibly recovers "balanced" distribution of bases for their electrochemical properties and thus "repairs" a high level of heterocatalytic DNA activity.
D000818:Animals; D005075:Biological Evolution; D003434:Crossing Over, Genetic; D004260:DNA Repair; D006801:Humans
Funktsiia krossingovera.