Bristle formation controlled by the achaete locus in genetic mosaics of Drosophila melanogaster.
نویسنده
چکیده
I N D. melanogaster, the genetic control of differentiation at specific sites is conveniently studied by the use of genetic mosaics. In wild-type flies, a definite number of macrochaetae or bristles is formed at specific sites of the thorax. Certain mutant genes are quite specific in their effects on bristle formation. The effect of achaete (ac) , for example, is primarily restricted to removal of two bristles, the anterior and posterior dorsocentrals. Earlier studies (STERN 1954a,b) have shown that bristle development is cell autonomous in mosaics. That is, in gynandromorphs in which the site of a posterior dorsocentral bristle is in ac tissue, a bristle will usually not differentiate even when most of the surrounding tissue is ac+. Conversely, when the site of the bristle is ac+, differentiation is always initiated regardless of the amount and distribution of surrounding ac tissue. This was interpreted by STERN as indicating that the hypodermal layer of the imaginal disc possesses regions in which the site of bristle formation is predetermined. A cell with the wild allele is competent to respond to this “prepattern,” but a cell with the ac allele lacks this competence. The present study of bristles affected by the ac locus uses a technique of mosaic production different from the one employed by STERN, one which produces a comparatively high proportion of mosaics thus permitting a quantitative breakdown of the various types of mosaics recovered.
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ورودعنوان ژورنال:
- Genetics
دوره 46 شماره
صفحات -
تاریخ انتشار 1961