  As 1998, the last year of the revised five-year plan and midpoint of the project's projected 15-year span, approached, many mapping goals had been met. In 1994, Généthon completed a genetic map with more than 2000 microsatellite markers at an average spacing of 2.9 cM and only one gap larger than 20 cM (Gyapay et al. 1994), though the genetic mapping phase of the project did not finally come to a close until March 1996 with publication of comprehensive genetic maps of the mouse and human genomes in Nature: the mouse map produced by scientists at Whitehead-MIT Center for Genome Research contained 7,377 genetic markers (both microsatellites and RFLPs) with an average spacing of 0.2 cM (Dietrich et al. 1996); the human map produced by scientists at Généthon contained 5,264 microsatellite markers located to 2335 positions with an average spacing of 1.6 cM (Dib et al. 1996). Physical mapping was on track: in 1995, a physical map with 94 percent coverage of the genome and STS markers at average intervals of 199 kb was published (T. Hudson et al. 1995), as was CEPH's updated physical map of 225 YAC contigs covering 75 percent of the genome (Chumakov et al. 1995); however, bacterial artificial chromosomes (BACs), developed in DOE-funded research at Caltech in 1992 (Shizuya et al. 1992), soon replaced YACs because of their greater stability in propagating DNA for sequencing. Sequencing itself presented more of a challenge. The genomes of the smallest model organisms had been sequenced. In April 1996, an international consortium of mostly European laboratories published the sequence for S. cerevisiae which was the first eukaryote completed, with 12 million base pairs and 5,885 genes and at a cost of $40 million (Goffeau et al. 1996). In January 1997, University of Wisconsin researchers completed the sequence of E. coli with 4,638,858 base pairs and 4,286 genes (Blattner et al. 1997). However, despite ramped-up sequencing efforts over the past several years at the Sanger Centre and NHGRI-funded centers (the NCHGR had been elevated to the status of a research institute in 1997 and renamed the National Human Genome Research Institute), with only three percent of the human genome sequenced, sequencing costs hovering at $.40/base, and the desired high-output not yet achieved by the sequencing centers, and about $1.8 billion spent, doubts existed about whether the target date of 2005 could be met.