title: Comparative analysis of expressed sequence tags of conifers and angiosperms reveals sequences specifically conserved in conifers.
abstract: To identify and characterize lineage-specific genes of conifers, two sets of ESTs (with 12791 and 5902 ESTs, representing 5373 and 3018 gene transcripts, respectively) were generated from the Cupressaceae species Cryptomeria japonica and Chamaecyparis obtusa. These transcripts were compared with non-redundant sets of genes generated from Pinaceae species, other gymnosperms and angiosperms. About 6% of tentative unique genes (Unigenes) of C. japonica and C. obtusa had homologs in other conifers but not angiosperms, and about 70% had apparent homologs in angiosperms. The calculated GC contents of orthologous genes showed that GC contents of coniferous genes are likely to be lower than those of angiosperms. Comparisons of the numbers of homologous genes in each species suggest that copy numbers of genes may be correlated between diverse seed plants. This correlation suggests that the multiplicity of such genes may have arisen before the divergence of gymnosperms and angiosperms.
authors.affiliation: Genome Analysis Laboratory, Department of Forest Genetics, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, 305-8687, Ibaraki, Japan. udino@ affrc.go.jp
authors.forename: Tokuko
authors.initials: T
authors.lastname: Ujino-Ihara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanamori
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yamane
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Taguchi
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Namiki
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Mukai
authors.forename: Kensuke
authors.initials: K
authors.lastname: Yoshimura
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Tsumura
mesh_terms: D001483:Base Sequence; D029780:Chamaecyparis / Q000235:genetics; D019295:Computational Biology; D017124:Conserved Sequence; D032485:Cryptomeria / Q000235:genetics; D018076:DNA, Complementary / Q000378:metabolism; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D018745:Genome, Plant; D019684:Magnoliopsida / Q000235:genetics*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism; D012984:Software; D064028:Tracheophyta / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D010455:Peptides; D012333:RNA, Messenger