Generation of 10,154 expressed sequence tags from a leafy gametophyte of amarine red alga, Porphyra yezoensis

A total of 10,154 5'-end expressed sequence tags (EST) were established fro m the normalized and size-selected cDNA libraries of a marine red alga, Por phyra yezoensis. Among the ESTs, 2140 were unique species, and the remainin g 8014 were grouped into 1127 species. Database search of the 3267 non-redu ndant ESTs by BLAST algorithm showed that the sequences of 1080 species (33 .1%) have similarity to those of registered genes from various organisms in cluding higher plants, mammals, yeasts, and cyanobacteria, while 2187 (66.9 %) are novel. Codon usage analysis in the coding regions of 101 non-redunda nt EST groups showing significant similarity to known genes indicated the h igher GC contents at the third position of codons (79.4%) than the first (6 2.2%) and the second position (45.0%), suggesting that the genome has been exposed to high GC pressure during evolution. The sequence data of individu al ESTs are available at the web site http://www.kazusa.or.jp/en/plantjporp hyra/EST/.