Heterochromatic Stellate Gene Cluster in Drosophila Melanogaster: Structure and Molecular Evolution

AUTOR(ES)

Tulin, A. V.

RESUMO

The 30-kb cluster comprising close to 20 copies of tandemly repeated Stellate genes was localized in the distal heterochromatin of the X chromosome. Of 10 sequenced genes, nine contain undamaged open reading frames with extensive similarity to protein kinase CK2 β-subunit; one gene is interrupted by an insertion. The heterochromatic array of Stellate repeats is divided into three regions by a 4.5-kb DNA segment of unknown origin and a retrotransposon insertion: the A region (~14 Stellate genes), the adjacent B region (approximately three Stellate genes), and the C region (about four Stellate genes). The sequencing of Stellate copies located along the discontinuous cluster revealed a complex pattern of diversification. The lowest level of divergence was detected in nearby Stellate repeats. The marginal copies of the A region, truncated or interrupted by an insertion, escaped homogenization and demonstrated high levels of divergence. Comparison of copies in the B and C regions, which are separated by a retrotransposon insertion, revealed a high level of diversification. These observations suggest that homogenization takes place in the Stellate cluster, but that inserted sequences may impede this process.

Documentos Relacionados

• Chromosome Rearrangement by Ectopic Recombination in Drosophila Melanogaster: Genome Structure and Evolution
• The fourth chromosome of Drosophila melanogaster: Interspersed euchromatic and heterochromatic domains
• The alpha-amylase gene in Drosophila melanogaster: nucleotide sequence, gene structure and expression motifs.
• Heterochromatic Position Effect at the Rosy Locus of DROSOPHILA MELANOGASTER: Cytological, Genetic and Biochemical Characterization
• Detailed Structure of the Drosophila Melanogaster Stellate Genes and Their Transcripts