The length of homology comparison, as described,may be over longer stretches, and in certain embodiments will often be over a stretch of about 17 to 20 nucleotides, preferably 21 to 25 nucleotides, more preferably 26 to 35 nucleotides, and more preferably about 36 or more nucleotides.The hybridization of polynucleotides is affected by such conditions as salt concentration, temperature, or organic