Aspects of the structure and development of monotreme spermatozoa and their relevance to the evolution of mammalian sperm morphology

Carrick F.N. and Hughes R.L. (1982) Aspects of the structure and development of monotreme spermatozoa and their relevance to the evolution of mammalian sperm morphology. Cell and Tissue Research, 222 1: 127-141. doi:10.1007/BF00218293


Author Carrick F.N.
Hughes R.L.
Title Aspects of the structure and development of monotreme spermatozoa and their relevance to the evolution of mammalian sperm morphology
Journal name Cell and Tissue Research   Check publisher's open access policy
ISSN 0302-766X
Publication date 1982-01-01
Sub-type Article (original research)
DOI 10.1007/BF00218293
Volume 222
Issue 1
Start page 127
End page 141
Total pages 15
Publisher Springer-Verlag
Subject 2702 Anatomy
1308 Clinical Biochemistry
1307 Cell Biology
Abstract The elongated spermatid nuclei of monotremes exhibit a circumferentially arranged spiral pattern of chromatin condensation, and ultimately form helical filiform sperm heads up to 50 μm long and either circular or slightly oval in transverse section. The acrosome is formed by the collapse of the proacrosomal vacuole onto the rostral surface of the elongating nucleus. However, genesis of acrosomal material occurs in the absence of a prominent proacrosomal granule. The flagellum becomes inserted into the distal extremity of the nucleus, the most proximal mitochondria of the midpiece directly abutting the nuclear membrane, so that a prominent neck region is absent. The axoneme is simple and, in the midpiece, small dense peripheral fibres are closely applied to the outer surface of each of the nine microtubule doublets. The cortical fibrous sheath of the principal piece is an anastomosing spiral that lacks lateral columnar elements. The spermatozoal cytoplasmic droplet undergoes migration and is lost during epididymal passage. Monotreme spermatozoa exhibit a montage of features, some of these being also found in marsupials and some in sauropsidan vertebrates, as well as a number of their own distinctive features. It is concluded that monotreme spermatozoa also have a close affinity with the unspecialised spermatozoa of some eutherian mammals.
Keyword Epididymal spermatozoa
Ornithorhynchus anatinus
Spermiogenesis
Tachyglossus aculeatus
Zaglossus bruijni
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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Created: Tue, 28 Jun 2016, 16:40:21 EST by System User