An important means for generating genetic diversity to provide raw material for evolution and maintain genomic stability is sexual reproduction. At the molecular level, the genes of two individuals are mixed through a process called homologous recombination. This process is found also in many simple life forms, even bacteria. At the beginning of recombination, two DNA duplexes, e.g., from mother and father, are aligned next to one another as the result of homology search, i.e., like strands are brought together with like strands. The four single DNA strands, two in each duplex, cross reciprocally two of the strands between the duplexes. The result is a joint molecule that contains DNA crossovers, named Holliday junctions. The Holliday junction is highly polymorphic in moving along two DNA duplexes, exchanging their DNA. Researchers are now investigating the physical mechanism of Holliday junction migration. The polymorphic, dynamic character of this migration makes observations difficult and the researchers resorted to molecular dynamics simulations using NAMD. The results, reported recently, resolved the dynamics of maternal-paternal DNA exchange through Holliday junction transitions in unprecedented detail providing an atomic level view of sexual reproduction. Check a brief review on our website.

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