MysTR copy numbers in three rodent species. Copy numbers for recently inserted mysTR elements were determined in O. palustris, S. hispidus, and P. maniculatus by three methods. Bars: □, numbers determined using oligonucleotide probes in dot blot hybridizations; ▨, numbers determined using 926-bp DNA probes in dot blot hybridizations; ▪, numbers determined using 926-bp DNA probes for library hybridizations. Clones identified by library hybridizations were sequenced and counted only if their divergence from probes was ≤10%.