title: Molecular cloning of zebra finch W chromosome repetitive sequences: evolution of the avian W chromosome.
abstract: The zebra finch (Taeniopygia guttata) has a large Z chromosome and highly condensed W chromosome. We used the random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) technique to isolate female-specific sequences ZBM1 and ZBM2. Southern blot hybridization to male and female zebra finch genomic DNA suggested that these sequences were located on the W chromosome, although homologous sequences appeared to be autosomal or Z-linked. Fluorescent in situ hybridization (FISH) using bacterial artificial chromosome (BAC) clones corresponding to ZBM sequences showed hybridization to the whole W chromosome, suggesting that the BACs encode sequences that are repeated across the entire W chromosome. Based on the sequencing of a ZBM repetitive sequence and Z chromosome derived BAC clones, we demonstrate a random distribution of repeat sequences that are specific to the W chromosome or encoded by both Z and W. The positions of ZW-common repeat sequences mapped to a noncoding region of a Z chromosome BAC clone containing the CHD1Z gene. The apparent lineage-specificity of W chromosome repeat sequences in passerines and galliform birds suggest that the W chromosome had not differentiated well from the Z at the time of divergence of these lineages.
authors.affiliation: Department of Physiological Science and Laboratory of Neuroendocrinology of the Brain Research Institute, University of California, Los Angeles, CA 90095-1606, USA.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Itoh
authors.forename: Kathy
authors.initials: K
authors.lastname: Kampf
authors.forename: Arthur P
authors.initials: AP
authors.lastname: Arnold
mesh_terms: D000818:Animals; D001483:Base Sequence; D001717:Birds; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D019105:Random Amplified Polymorphic DNA Technique; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D012730:Sex Chromosomes / Q000235:genetics*; D013045:Species Specificity