Larsson Jan, Meller Victoria H
Umeå Center for Molecular Pathogenesis, Umeå University, SE-901 87, Umeå, Sweden.
Chromosome Res. 2006;14(4):417-31. doi: 10.1007/s10577-006-1064-3.
Over the past 100 years Drosophila has been developed into an outstanding model system for the study of evolutionary processes. A fascinating aspect of evolution is the differentiation of sex chromosomes. Organisms with highly differentiated sex chromosomes, such as the mammalian X and Y, must compensate for the imbalance in gene dosage that this creates. The need to adjust the expression of sex-linked genes is a potent force driving the rise of regulatory mechanisms that act on an entire chromosome. This review will contrast the process of dosage compensation in Drosophila with the divergent strategies adopted by other model organisms. While the machinery of sex chromosome compensation is different in each instance, all share the ability to direct chromatin modifications to an entire chromosome. This review will also explore the idea that chromosome-targeting systems are sometimes adapted for other purposes. This appears the likely source of a chromosome-wide targeting system displayed by the Drosophila fourth chromosome.
在过去的100年里，果蝇已发展成为研究进化过程的杰出模式系统。进化的一个迷人方面是性染色体的分化。具有高度分化性染色体的生物，如哺乳动物的X和Y染色体，必须补偿由此产生的基因剂量不平衡。调节性连锁基因表达的需求是推动作用于整条染色体的调控机制兴起的一股强大力量。本综述将对比果蝇中的剂量补偿过程与其他模式生物所采用的不同策略。虽然每种情况下性染色体补偿的机制不同，但它们都具有将染色质修饰导向整条染色体的能力。本综述还将探讨染色体靶向系统有时会被用于其他目的这一观点。这似乎是果蝇第四条染色体所展示的全染色体靶向系统的可能来源。
