Nonsister chromatids of homologous chromosomes may exchange genetic information over regions of homology. Recombination can occur between DNA sequences that contain no sequence homology. NRF2 possesses six highly conserved domains called NRF2-ECH homology (Neh) domains. This theorem also underlies the duality between de Rham cohomology and the homology of chains. Generally these techniques require high sequence homology between parental sequences. These invariants are polynomials on the second homology. The most important of these invariants are homotopy groups, homology, and cohomology. These aspects include identity, similarity, and homology. These methods are based upon the homology of proteins. Some versions of cohomology arise by dualizing the construction of homology. Simplicial complexes are used to define a certain kind of homology called simplicial homology. The lyssavirus genus can be divided into four phylogroups based upon DNA sequence homology. Phospholipases A2 can be classified based on sequence homology. The chromatic polynomial is categorified by a homology theory closely related to Khovanov homology. Innexins have no significant sequence homology with connexins.