Wakimoto B T, Hearn M G
Department of Zoology NJ-15, University of Washington, Seattle 98195.
Genetics. 1990 May;125(1):141-54. doi: 10.1093/genetics/125.1.141.
The light (lt) gene of Drosophila melanogaster is located at the base of the left arm of chromosome 2, within or very near centromeric heterochromatin (2Lh). Chromosome rearrangements that move the lt+ gene from its normal proximal position and place the gene in distal euchromatin result in mosaic or variegated expression of the gene. The cytogenetic and genetic properties of 17 lt-variegated rearrangements are described in this report. We show that five of the heterochromatic genes adjacent to lt are subject to inactivation by these rearrangements and that the euchromatic loci in proximal 2L are not detectably affected. The properties of the rearrangements suggest that proximity to heterochromatin is an important regulatory requirement for at least six 2Lh genes. We discuss how the properties of the position effects on heterochromatic genes relate to other proximity-dependent phenomena such as transvection.
黑腹果蝇的光（lt）基因位于2号染色体左臂的基部，在着丝粒异染色质（2Lh）内部或非常靠近着丝粒异染色质的位置。将lt +基因从其正常近端位置移动并将该基因置于远端常染色质中的染色体重排会导致该基因的镶嵌或斑驳表达。本报告描述了17种lt - 斑驳重排的细胞遗传学和遗传学特性。我们表明，与lt相邻的五个异染色质基因会因这些重排而失活，而近端2L中的常染色质位点未受到可检测到的影响。重排的特性表明，靠近异染色质是至少六个2Lh基因的重要调控条件。我们讨论了位置效应在异染色质基因上的特性如何与其他邻近依赖性现象（如顺反效应）相关。
