Biology Reference
In-Depth Information
Fig. 5.12 Spermatogenesis: Centriolar dynamics images of centrioles, single and duplicating, in
spermatogenic cells at interphase. Note dense pericentriolar material. RS round spermatids, S0
spermatogonium, S1 primary spermatocyte x85,000, x102,000
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5.7 The Zygote Centrosome
The zygote centrosome appears to be a blending of both paternal and maternal
components as revealed by fluorescent microscopy (FM) and TEM and more
recently by molecular studies (Sathananthan et al.
1996
; Schatten
1994
,
2008
;
Simerly et al.
1995
; Sutovsky and Schatten
1999
). There appears to be a pro-
gressive addition of granular PCM around the duplicated sperm centriole from the
pronuclear stage to syngamy, soon after fertilization (Sathananthan et al.
1996
;
Sathananthan
1997
,
1998
). This PCM nucleates MTs of the sperm monoaster after
sperm fusion and incorporation (Figs.
5.18
,
5.19
), which duplicates to form the
two poles of the first bipolar mitotic spindle (Figs.
5.20
,
5.25
). Two centrioles
compose the heart of the zygote centrosome soon after its release from the 'black
box'. The sperm centriole is duplicated, while acquiring increasingly dense PCM
