OBSERVATIONS ON SPERMIOGENESIS IN THE FUNGUS GNAT SCIARA COPROPHILA
نویسندگان
چکیده
منابع مشابه
Observations on Spermiogenesis in the Fungus Gnat Sciara Coprophila
Although 9-membered centrioles are found in somatic tissues of Sciara, the centriole which lies at the spindle pole of the second meiotic division in male Sciara is composed of a row of approximately 70 short tubules in an oval array. Shortly after telophase of this unequal division, in the daughter cell destined to undergo spermiogenesis, microtubules become confluent with the tubules of the c...
متن کاملFine Structure of Sciara Coprophila Sperm
Though the fagellum of Sciara sperm arises from a blepharoplast and is characterized by doublet tubules with arms, it differs markedly from the familiar type of flagella in the number and arrangement of its tubules. The axial filament complex in sperm from the testis of Sciara consists of approximately 70 doublet tubules, each with an associated singlet tubule. Near the nucleus these tubules ar...
متن کاملA Study of the Nucleolar Material in Sciara Coprophila
In the polytene chromosomes of Sciara coprophila, in addition to a nucleolus, large numbers of nucleolarlike structures or micronucleoli are formed. A detailed mapping localized the nucleolar organizer at one end of the X chromosome and revealed that approximately 18% of the bands of each chromosome are potentially capable of producing micronucleoli. Most of these sites are in regions known fro...
متن کاملFurther studies on the ribosomal RNA cistrons of Sciara coprophila (Diptera).
Additional experiments with homologous as well as heterologous hybridization confirmed our previous finding in Sciara coprophila that XX females have nearly twice the number of ribosomal RNA cistrons as XO males. A comparison between two different X' chromosomes revealed that only the one carrying the irradiation-induced Wavy mutation has a deletion of 70% of its ribosomal RNA cistrons as compa...
متن کاملMeiosis in Sciara coprophila: structure of the spindle and chromosome behavior during the first meiotic division
Light microscope descriptions of meiosis I in males of the fungus gnat Sciara coprophila suggested the presence of a monopolar spindle in which maternal and limited chromosomes move poleward while paternal chromosomes "back away" from the pole. The ultrastructural analysis reported here, based upon serial sections of cells in different stages of meiosis I, shows that the spindle is indeed monop...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Cell Biology
سال: 1966
ISSN: 1540-8140,0021-9525
DOI: 10.1083/jcb.30.3.477