Alton A K, Fechtel K, Terry A L, Meikle S B, Muskavitch M A
Department of Biology, Indiana University, Bloomington 47405.
Genetics. 1988 Feb;118(2):235-45. doi: 10.1093/genetics/118.2.235.
We have conducted a genetic analysis of a small interval of the third chromosome known to include Delta (Dl), a locus that affects the segregation of the ectoderm into neural and epidermal lineages during embryogenesis and the morphogenesis of some ectodermally derived structures, in Drosophila melanogaster. This analysis has led to the definition of seven independent complementation groups, one of which is Delta, within the interval extending from 91F6-13 to 92A2. Among the extant mutations in these seven loci, only mutations in Dl lead to the so-called neurogenic phenotype: hypertrophy of the nervous system and reduction of the epidermis. Combined cytogenetic and genetic analyses allow us to define absolute proximal (91F5-92A1) and distal (92A2) cytogenetic limits for the Dl locus. We have isolated hypomorphic and amorphic alleles of Dl and find that, for any given allele, there is an inverse correlation between neural hypertrophy and epidermal reduction in embryos and a direct correlation between the severity of embryonic phenotypes in mutant homozygotes and hemizygotes and the imaginal phenotype in heterozygous adults.
我们对黑腹果蝇第三号染色体上一个已知包含Delta（Dl）基因座的小区间进行了遗传分析。Delta基因座在胚胎发育过程中影响外胚层分化为神经和表皮谱系，以及一些外胚层衍生结构的形态发生。该分析确定了从91F6 - 13延伸至92A2区间内的七个独立互补群，其中之一就是Delta。在这七个基因座的现有突变中，只有Dl基因座的突变会导致所谓的神经源表型：神经系统肥大和表皮减少。结合细胞遗传学和遗传学分析，我们能够确定Dl基因座的绝对近端（91F5 - 92A1）和远端（92A2）细胞遗传学界限。我们分离出了Dl的亚效等位基因和无效等位基因，并发现，对于任何给定的等位基因，胚胎中的神经肥大与表皮减少呈负相关，突变纯合子和半合子中胚胎表型的严重程度与杂合子成虫的成虫盘表型呈正相关。
