ISSN:
1573-5117
Keywords:
aquatic Oligochaeta
;
spermatozoa
;
spermatogenesis
;
cell differentiation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Spermiogenesis in Oligochaeta occurs with peculiar modalities, common to all the species studied in this group. Gonial cells, produced in the testes, drop into coelomatic cavities (usually seminal vesicles) where they undergo a series of mitotic divisions, without cytodieresis, and finally meiosis. In the seminal vesicles, a series of ‘morulae’ is present, composed of 2, 4, 8, 18, 32, ... cells. The number of spermatids produced is variable, but is constant for each species. The process of spermiohistogenesis involves many steps, including: nuclear shaping, chromatin condensation, production of an acrosome, reduction of the number of mitochondria. The present knowledge of the mechanisms of cell differentiation, and the problem of the presence of two different sperm lines in some species is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00027894
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