Characterization of a 10 cM region of rice chromosome 5

Rice is a model species for the cereals and a good candidate for genome seq uencing due to its relatively small genome (430 Mb), dense physical and gen etic maps, and good transgenic systems. As part of an international effort to decode the rice genome, a PAC clone localized at 10 cM of chromosome 5 i s completely determined for its sequence using shotgun libraries of its two inserts, 2-kb and 5-kb in length. In total 2,998 sequencing reads were use d for the assembly of the final sequence, covering 175,439 bp. This sequenc e may code for at least 28 putative proteins, as deduced from computational search for homology with other known coding sequences and EST, or predicte d using GenScan package. Also present in this sequence are simple repeats, palindrome and retrotransposons. On the basis of these findings, the gene d ensity in the gene-rich region of rice genome is about 6 kb/gene.