title: A comprehensive collection of chicken cDNAs.
abstract: Birds have played a central role in many biological disciplines, particularly ecology, evolution, and behavior. The chicken, as a model vertebrate, also represents an important experimental system for developmental biologists, immunologists, cell biologists, and geneticists. However, genomic resources for the chicken have lagged behind those for other model organisms, with only 1845 nonredundant full-length chicken cDNA sequences currently deposited in the EMBL databank. We describe a large-scale expressed-sequence-tag (EST) project aimed at gene discovery in chickens (http://www.chick.umist.ac.uk). In total, 339,314 ESTs have been sequenced from 64 cDNA libraries generated from 21 different embryonic and adult tissues. These were clustered and assembled into 85,486 contiguous sequences (contigs). We find that a minimum of 38% of the contigs have orthologs in other organisms and define an upper limit of 13,000 new chicken genes. The remaining contigs may include novel avian specific or rapidly evolving genes. Comparison of the contigs with known chicken genes and orthologs indicates that 30% include cDNAs that contain the start codon and 20% of the contigs represent full-length cDNA sequences. Using this dataset, we estimate that chickens have approximately 35,000 genes in total, suggesting that this number may be a characteristic feature of vertebrates.
authors.affiliation: Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology, P.O. Box 88, M60 1QD, Manchester, United Kingdom.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Boardman
authors.forename: Juan
authors.initials: J
authors.lastname: Sanz-Ezquerro
authors.forename: Ian M
authors.initials: IM
authors.lastname: Overton
authors.forename: David W
authors.initials: DW
authors.lastname: Burt
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Bosch
authors.forename: Willy T
authors.initials: WT
authors.lastname: Fong
authors.forename: Cheryll
authors.initials: C
authors.lastname: Tickle
authors.forename: William R A
authors.initials: WR
authors.lastname: Brown
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Wilson
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Hubbard
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002645:Chickens / Q000235:genetics*; D002874:Chromosome Mapping / Q000379:methods; D018076:DNA, Complementary / Q000235:genetics*; D020224:Expressed Sequence Tags; D012689:Sequence Homology, Nucleic Acid
chemical_list: D018076:DNA, Complementary