Before revision:  To show this, we used ectopic integration to characterize cells that carry either the MRE11 or mre11A470T alleles at the genomic g site, and a second opposing mre11A470T or MRE11 allele, respectively, at an ectopic site.
After revision:  To show this, we used ectopic integration to characterize cells that carry either the MRE11 or mre11A470T alleles at the genomic  site, and a second opposing mre11A470T or MRE11 allele, respectively, at an ectopic site.