Heteroduplex
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204683791
2008-04-10T13:15:25Z
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A '''heteroduplex''' is a double-stranded ([[duplex]]) molecule of [[nucleic acid]] originated through the [[genetic recombination]] of single complementary strands derived from different sources, such as from different homologous [[chromosomes]] or even from different [[organisms]].
One such example is the heteroduplex DNA strand formed in [[DNA hybridization|hybridization]] processes, usually for [[biochemistry]]-based [[phylogenetic]]al analyses. Another example is the heteroduplexes formed when non-natural analogs of nucleic acids are used to bind with nucleic acids; these heteroduplexes result from performing [[antisense]] techniques using single-stranded [[peptide nucleic acid]], [[2'-O-methyl phosphorothioate]] or [[Morpholino]] [[oligos]] to bind with RNA.
In meiosis, the process of crossing-over occurs between non-sister chromatids, which results in new allelic combinations of a population. In crossing-over, a SpoII enzyme makes staggered nicks in a pair of sister chromatid strands (in a tetrad organization of prophase). The enzyme trims back the 5' ends of the strand and a protein complex binds to the 3' single-stranded ends. Rad51 protein is recruited and binds in a protein complex to search for a complementary sequence analogous to double-strand-break repair. The filament searches for the homologous chromosome, strand invasion occurs where the new chromosome forms a D-loop over the bottom sister chromatid, then the ends are annealed. This process can yield double Holliday Junctions that when cut in a transversal pattern by endonucleases form 2 heteroduplex strand products.
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