Cytology and Development of the Embryos of X-Rayed Adult Drosophila Melanogaster

Abstract

GENETICS: B. P. SONNENBLICK in only chromatid aberrations including a considerable number of simple chromatid deletions and occasional chromatid exchanges Ultra-violet radiation of the generative nucleus in the pollen tube induces only simple chromatid deletions. The loss of only one of the two chromatids is in accord with the genetic observations that ultra-violet radiation produces primarily fractional endosperm deficiencies in maize. No configurations representing an interchange of chromatin between non-homologous chromosomes were found.The qualitative difference between the types of breaks induced by x-ray and ultra-violet radiation is tentatively explained by assuming that the sphere of influence of a single x-ray quantum is much greater in area than that of a single ultra-violet quantum. The vast difference in energy values, and the difference in the physical behavior attendant to absorption of the respective quanta supply a possible physical and chemical basis for this variation in degree of effectiveness.

Jak-STAT regulation of cyst stem cell development in the Drosophila testis

“…At the onset of testis formation, migrating primordial germ cells (PGCs) contact somatic gonadal precursor (SGP) cells specified with bilateral symmetry in embryonic parasegments (PS) 10–12 of the gonadal mesoderm at ~7 hrs AEL (Boyle et al, 1997; Boyle and DiNardo, 1995; Brookman et al, 1992; Sonnenblick, 1941). PGCs and SGPs then compact into a spherical gonad by ~10.5 hrs AEL, with SGPs fully ensheathing the PGCs (Boyle and DiNardo, 1995; Jenkins et al, 2003; Van Doren et al, 2003; Warrior, 1994; Weyers et al, 2011).…”

The Detection and Nature of Dominant Lethals in Lilium. Ii. Cytological Abnormalities in Ovules After Pollen Irradiation

“…DISCUSsION.-In studying the cytology of Drosophila embryos, developing from the union of one set of irradiated chromosomes from either the egg or sperm and one set of normal chromosomes, Sonnenblick (1940) found abnormalities similar to those just described in lily. Differentiation of Drosophila embryos was disturbed to the extent that they were sometimes only structureless masses of cells.…”

“…In animals Sonnenblick (1940) described the cytology and development of Drosophila melanogaster embryos containing one set of X-rayed chromosomes from either the sperm or the egg. Within single eggs abnormalities of various types occurred, such as clumped chromosomes, multipolar spindles, fractured chromosomes, fragments, asymmetrical distribution of chromatin, and pycnotic masses connected by chromosomal strands.…”

Cytogenetic effects of 2,4,5-trichlorophenoxy-acetic acid on oogenesis and early embryogenesis in Drosophila melanogaster

“…The degenerated follicles of stages 9 and 10 resemble degenerated follicles caused by the sterility gene diminutive (dm). SONNENBLICK (1940) has shown that the most mature oocytes are especially susceptible to irradiation. This was verified by KING and his co-workers (1956), who showed that a high frequency of dominant lethal mutations, X-chromosome losses and recessive lethal mutations were easily induced at the time of the meiotic metaphase I.…”