What is the significant of transgene copy number?
For the majority of transgenes the copy number does not correlate with expression level. The exceptions occur when large genomic fragments are used to make transgenics. Examples include P1 clones (90 Kb), BACs (180 Kb,) or YACs (400 Kb). Some reports suggest that if you use locus control regions or matrix attachment regions around your transgene that you may be able to insulate if form integration effects. Previous work in the literature has shown that attempts to produce low copy numbers by microinjecting dilute DNA does not affect copy number, but does reduce the overall yield of transgenic mice.
