Concerning the Stereochemistry of Strand Equivalence in Genetic Recombination
In their article describing the nature of crossed-strand exchange between homologous DNA molecules (a likely intermediate in genetic recombination), Sigal and Alberts (1972) have demonstrated the stereochemical feasibility of a connection in which all bases remain paired without undue bond strain or unfavorable contacts. They have provided the important additional observation that such a junction can migrate by a rotary diffusion mechanism; this would involve the exchange of two identical bases above or below the cross-connection, with an accompanying rotation of both helices in the same sense about their helical axes. Such a process could be rapid enough to account for the formation of extensive regions of hybrid DNA during genetic recombination (Meselson, 1972).
KeywordsFlank Marker Genetic Recombination Strand Exchange Synaptic Structure Helical Axis
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