RESUMEN
A physical map of the euchromatic X chromosome of Drosophila melanogaster has been constructed by assembling contiguous arrays of cosmids that were selected by screening a library with DNA isolated from microamplified chromosomal divisions. This map, consisting of 893 cosmids, covers approximately 64% of the euchromatic part of the chromosome. In addition, 568 sequence tagged sites (STS), in aggregate representing 120 kb of sequenced DNA, were derived from selected cosmids. Most of these STSs, spaced at an average distance of approximately 35 kb along the euchromatic region of the chromosome, represent DNA tags that can be used as entry points to the fruitfly genome. Furthermore, 42 genes have been placed on the physical map, either through the hybridization of specific probes to the cosmids or through the fact that they were represented among the STSs. These provide a link between the physical and the genetic maps of D. melanogaster. Nine novel genes have been tentatively identified in Drosophila on the basis of matches between STS sequences and sequences from other species.
Asunto(s)
Mapeo Cromosómico , Cósmidos , Drosophila melanogaster/genética , Lugares Marcados de Secuencia , Cromosoma X , Secuencia de Aminoácidos , Animales , Secuencia de Bases , ADN , Datos de Secuencia Molecular , Homología de Secuencia de AminoácidoRESUMEN
We have introduced an N-terminally truncated form of cyclin B into the Drosophila germ-line downstream of the yeast upstream activator that responds to GAL4. When such lines of flies are crossed to lines in which GAL4 is expressed in imaginal discs and larval brain, the majority of the resulting progeny die at the late pupal stage of development. Very rarely (< 0.1% of progeny) adults emerge that have a mutant phenotype typical of flies with mutations in genes required for the cell cycle; they have rough eyes, deformed wings, abnormal bristles, and die within hours of emergence. The brains of third instar larval progeny show an abnormally high proportion of mitotic cells containing overcondensed chromatids that have undergone anaphase separation, together with cells that cannot be assigned to a particular mitotic stage. Immunostaining indicates that these anaphase cells contain moderate levels of cyclin B, suggesting that persistent p34cdc2 kinase activity can prevent progression from anaphase into telophase.
Asunto(s)
Anafase/fisiología , Encéfalo/metabolismo , Ciclinas/biosíntesis , Drosophila/metabolismo , Mitosis/fisiología , Proteínas del Tejido Nervioso/biosíntesis , Fragmentos de Péptidos/biosíntesis , Animales , Secuencia de Bases , Cromátides , Ciclinas/química , Larva/metabolismo , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/química , Fragmentos de Péptidos/química , Huso Acromático , Factores de TiempoRESUMEN
We are constructing a molecular physical map of the Drosophila melanogaster genome, using microdissection of polytene chromosomes as a source of region specific probes applied to direct mapping work. Chromosome microdissection has been used for a low resolution map of the Anopheles gambiae s.s. genome.