Stopping points for bacterial artificial chromosome (BAC) shotgun sequencing based on confidence levels for closure of 90% and 95%. Short clones averaging 58 kb (Diaz-Perez et al. 1997) were evaluated using equation 4, whereas “typical clones” of 150 kb (IHGSC, 2001) and longer clones of 235 kb (Wendl et al. 2001) were determined using equation 9.