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.
A 5kb insertion of aurora-element in SteXh has 234bp LTRs differing from each other by a single mismatch and a 5bp duplication of the integration site relative to the intact SteXh gene sequence. Southern analysis of various stocks reveals there are a few dozen aurora-element copies per fly genome. These copies are non-mobile as unrelated stocks show essentially the same hybridization pattern. Nearly all the copies are underreplicated and must be located in the heterochromatin. Two major aurora-element variants are seen 4.5kb and 4.8kb. The aurora-element is present in the melanogaster species group.
The divergence of the left and right LTRs of heterochromatic aurora-element and mdg1 elements indicates that aurora-element has been at its heterochromatic location for 0-0.15Myr and mdg1 for 0-0.7Myr.
ninja-Dsim-like{}649 shows reduced transcript levels in rib mutant embryos compared to in wild-type embryos.
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.
A 5kb insertion of aurora-element in SteXh has 234bp LTRs differing from each other by a single mismatch and a 5bp duplication of the integration site relative to the intact SteXh gene sequence. Southern analysis of various stocks reveals there are a few dozen aurora-element copies per fly genome. These copies are non-mobile as unrelated stocks show essentially the same hybridization pattern. Nearly all the copies are underreplicated and must be located in the heterochromatin. Two major aurora-element variants are seen 4.5kb and 4.8kb. The aurora-element is present in the melanogaster species group.
The divergence of the left and right LTRs of heterochromatic aurora-element and mdg1 elements indicates that aurora-element has been at its heterochromatic location for 0-0.15Myr and mdg1 for 0-0.7Myr.