Article Abstract:
The chromosomal heterochromatic and euchromatic genes differ in regulatory requirements and the rearrangements can cause mosaic inactivation of these genes. Heterochromatin and euchromatin are functionally different in terms of gene expression and this is confirmed from studies on position effect variegation (PEV). Moving a gene from its normal position to another site causes mosaic inactivation and an example of PEV is the heterochromatin- induced inactivation of the euchromatin white+ gene forming a mosaic red and white eye phenotype.
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Article Abstract:
The abnormal oocyte1 (abo1) is one of five closely-related recessive maternal effect mutations that have been identified with heterochromatin analysis of the Drosophila melanogaster. Heterochromatic regions that interact with abo1 have been designated ABO, with functions in either oogenesis or in egg prior to meiosis I completion. A P-element-induced allele, abo2, has been isolated to examine abo maternal-effect lethality. Preblastoderm lethality is generated by a recessive fertilization defect linked with the abo1 chromosome.
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Article Abstract:
A novel 1.7 kilobase middle repetitive DNA fragment called Bari-1 is discovered in Drosophila melanogaster. Most copies of the fragment is present in a few homogeneous clusters near the centromere of chromosome 2. Molecular analysis reveal that, independent of location, the fragment has the same reading frame. Its gene product bears resemblance to the transposase of Caenorhabditis elegansTc1 transposon.
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