60kb repeats located in the distal heterochromatin of the X chromosome have been cloned. These regions, designated as SCLRs, are comprised of the following types of repeated elements: SteXh, copia-like elements (mdg1 elements, aurora-elements and GATE elements), LINE-elements (G-elements and R1-elements), and bb fragments. There are approximately 9 SCLR copies per haploid genome, with a twofold variation in copy number between different fly stocks.
Stability of 11 transposable element families compared by Southern blotting among individuals of lines that had been subjected to 30 generations of sister sib matings. 412, roo, blood, 297, 1731 and G-element all appear stable, whereas copia, hobo, I-element, gypsy and jockey elements show instability.
A number of G-elements have been cloned and sequenced. G-elements lack terminal repeats, generate target-site duplications at the point of insertion and have a stretch of A residues of variable length at one end. G-elements are often inserted into the nontranscribed spacer (NTS) of the rDNA units encoded by bb.
G-elements are mostly located in heterochromatin.
One of a class of genes with TATA-less promoters that have the conserved DPE sequence.
The distribution of transposable elements within heterochromatin indicates that they are major structural components of the heterochromatin.
60kb repeats located in the distal heterochromatin of the X chromosome have been cloned. These regions, designated as SCLRs, are comprised of the following types of repeated elements: SteXh, copia-like elements (mdg1 elements, aurora-elements and GATE elements), LINE-elements (G-elements and R1-elements), and bb fragments. There are approximately 9 SCLR copies per haploid genome, with a twofold variation in copy number between different fly stocks.
Stability of 11 transposable element families compared by Southern blotting among individuals of lines that had been subjected to 30 generations of sister sib matings. 412, roo, blood, 297, 1731 and G-element all appear stable, whereas copia, hobo, I-element, gypsy and jockey elements show instability.
A number of G-elements have been cloned and sequenced. G-elements lack terminal repeats, generate target-site duplications at the point of insertion and have a stretch of A residues of variable length at one end. G-elements are often inserted into the nontranscribed spacer (NTS) of the rDNA units encoded by bb.