种间黑腹果蝇杂种 rRNA 基因座的研究。Ⅱ.介导核仁优势的异染色质区域。
Studies on the Ribosomal RNA Cistrons in Interspecific Drosophila Hybrids. II. Heterochromatic Regions Mediating Nucleolar Dominance.
机构信息
Genetics and Cell Biology Section, Biological Sciences Group, University of Connecticut, Storrs, Connecticut 06268.
出版信息
Genetics. 1978 May;89(1):37-64. doi: 10.1093/genetics/89.1.37.
Interspecific hybrids of D. melanogaster and D. simulans normally exhibit a secondary constriction only at the D. melanogaster nucleolus organizer (NO). This phenomenon, termed nucleolar dominance, occurs only when the NO-bearing sex chromosomes of both species are present in conjunction. Experiments were initiated to localize regions on the sex chromosomes of D. melanogaster involved in mediating this suppression. Sex chromosome heterochromatic rearrangements and deficiencies were introduced into F(1) hybrids and their corresponding effect on simulans NO constriction formation was examined in hybrid mitotic neuroblast tissue. Sex chromosomes deficient for both the D. melanogaster NO and adjacent heterochromatin were unable to restrict the formation of a constriction at the D. simulans NO. The presence of a D. melanogaster NO, however, was not sufficient for the establishment of nucleolar dominance. Results from an array of NO-bearing X and Y chromosome rearrangements and deficiencies indicate that at least one heterochromatic region, proximal to the NO on the D. melanogaster X and distal to the NO on the D. melanogaster Y, affects the induction of this interchromosomal phenomenon.
黑腹果蝇和拟暗果蝇的种间杂种通常只在黑腹果蝇核仁组织区（NOR）显示出第二个缢痕。这种现象称为核仁优势，仅当两种物种的带有 NOR 的性染色体同时存在时才会发生。实验开始定位黑腹果蝇性染色体上参与介导这种抑制的区域。将性染色体异染色质重排和缺失引入 F1 杂种中，并在杂种有丝分裂神经母细胞组织中检查它们对拟暗果蝇 NOR 缢痕形成的影响。既缺乏黑腹果蝇 NOR 又缺乏相邻异染色质的性染色体无法限制拟暗果蝇 NOR 处缢痕的形成。然而，黑腹果蝇 NOR 的存在不足以建立核仁优势。一系列带有 NOR 的 X 和 Y 染色体重排和缺失的结果表明，至少有一个异染色质区域，靠近黑腹果蝇 X 上的 NOR，远离黑腹果蝇 Y 上的 NOR，影响了这种染色体间现象的诱导。
Zotero 插件