G-4 DNA is a four-stranded structure involving four parallel, identical, guanine-rich sequences, with the guanines Hoogsteen-paired. Such elements are able to crosslink four Watson-Crick duplexes. Since during meiosis the pairing of chromosomes after DNA replication involves four copies of each chromatid, which must synapse together before recombination takes place, we suggest that a self-recognition of guanine-rich motifs in DNA to form G4-DNA crosslinks cause the synapsis. G4-DNA crosslinks may also be used to align chromosomes in mitosis and in the formation of polytene chromosomes. To test the hypothesis that G4-DNA-forming regions serve as identification signals for chromosome matching, anti-G4-DNA antibodies will be used to detect G4- DNA in chromosomes during meiotic pairing. Anti-G4-DNA antibodies will be developed and used to detect G-4 regions that may crosslink chromosomes both with peroxidase and fluorescence methods. This will require extensive use of high-resolution microscopy to examine chromosome figures in meiotic cells. The results of this work, if supportive of the working hypothesis, will result in a major breakthrough in our understanding of a fundamental aspect of genetic inheritance, meiotic segregation.
