Genomic distribution of genes encoding 68 cytoplasmic ribosomal protein families in rice Subhash Mohan Agarwal 1*+ , Mukesh Jain 2+ , Atul Grover 3+ 1 Department of Chemistry, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India 2 Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India 3 Department of Biotechnology, Ch. Charan Singh University, Meerut 250005, India + All authors have contributed equally Key words: Ribosomal proteins, Multigene family, Duplication, Rice Abstract Completion of rice genome sequencing has necessitated iden- tification of transcripts encoded by the genome and their corre- sponding functions. In the present study we have catalogued cytoplasmic ribosomal protein complement of rice genome corresponding to 68 families. Mining TIGR (The Institute for Genomic Research) rice database and unigene sequences available from National Centre for Biotechnology Information (NCBI) produced a non-redundant set of these sequences. This resulted in identification of 209 candidate r-proteins of which 22 have not been reported previously. The number of genes per family ranges from 1 to 8 distributed throughout the genome with maximum occurrence at chromosome 7. Mapping of r-proteins on BAC clones revealed several small clusters of genes. Unigene sequences corresponding to most of the re- ported r-proteins were identified indicating these genes are be- ing expressed. List of abbreviations: r-proteins- ribosomal pro- teins, TIGR- The Institute of Genomic Research, NCBI- National Center for Biotechnology Infor- mation Introduction Cereals are the main source of dietary calories for most of the human population. They are a large and diverse set of agronomically important crops from the family Gramineae. Rice, because of its small genome continues to be a model plant among the monocot cereal crops for genetic and molecular studies (Devos and Gale 2000). It was estimated to be approximately 430 megabases (Mb) split across 12 chromosomes. Recently rice genome projects have published their data (Goff et al. 2002, Yu et al. 2002). Also a complete map based sequence of chromosome 1 (Sasaki et al. 2002) and chromo- some 4 for Oryza sativa L. cv. Nipponbare (Feng et al. 2002) respectively were published. This has provided a rich source for understanding the bio- logical processes in rice. Also with the recent ex- plosion of rice genomic data, the accurate and pre- cise characterization, description and classification of genetic elements encoded by rice DNA have be- come extremely important tasks. Furthermore, most cereal genes have strong rice homologs mak- ing its genome a useful foundation to identify genes in other cereals. Ribosome being the site of protein synthesis forms the core of translation machinery. 439 ACTA PHYSIOLOGIAE PLANTARUM Vol. 27. No. 4A. 2005: 439-446