title: Structure of Kluyveromyces lactis subtelomeres: duplications and gene content.
abstract: We have constructed a map of the duplicated regions of Kluyveromyces lactis subtelomeres. Seven out of 12 subtelomeres contain an almost identical 9 kb long segment starting from the end. This segment is bordered by a long terminal repeat element. Two of the subtelomeres share sequence similarity that extends over a total of 20 kb. The other subtelomeres also contain duplicated regions of 1-6 kb. Nonduplicated regions contain unique genes and genes from paralog families. All duplicated segments are in the same orientation with respect to the telomere, probably as a result of genetic exchange. We map the only two copies of retrotransposons in the genome, in subtelomeres. Low-complexity gene sequences that encode threonine- and serine-rich peptides are associated with the subtelomeres of K. lactis, as in Saccharomyces cerevisiae. The ubiquity of these sequences in hemiascomycete genomes, and the propensity they have to encode proteins with extracellular localization, make these genes ideal candidates for fast evolving 'contingency' genes involved in the adaptation of a species to its environment.
authors.affiliation: Unité de Génétique Moléculaire des Levures, Département Structure et Dynamique des Génomes, Institut Pasteur, Paris, France. cfair@pasteur.fr
authors.forename: Cécile
authors.initials: C
authors.lastname: Fairhead
authors.forename: Bernard
authors.initials: B
authors.lastname: Dujon
mesh_terms: D000595:Amino Acid Sequence; D005075:Biological Evolution; D015825:Chromosomes, Fungal / Q000235:genetics*; D019295:Computational Biology; D004271:DNA, Fungal / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D007716:Kluyveromyces / Q000235:genetics*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000235:genetics; D018626:Retroelements; D012441:Saccharomyces cerevisiae / Q000235:genetics; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D016615:Telomere / Q000235:genetics*; D020079:Terminal Repeat Sequences
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D021382:Protein Sorting Signals; D018626:Retroelements