To better understand the process of the simultaneous formation of the first two polar bodies
in an androgenetic clam, the meiotic process was observed by visualizing cytoskeletal elements, such as microtubules and centrosomes, and distribution of actin.
Comparative genomic hybridization analysis of human oocytes and polar bodies
. Hum Reprod.
One attachment is located anterior to the chondrocranium at the anterior trabeculae, another attachment is at the polar bodies
, and the third is a posterior attachment at the otic capsule (containing the inner ear).
The aim of the present study was to investigate the release of polar bodies
and monitor meiotic development, including the most frequent number of chromosomes in Anomalocardia brasiliana, to establish a basis for future chromosome manipulation for aquaculture purposes.
Verlhac et al found that in mouse oocytes, [mos.sup.-/-] oocytes extruded their first polar bodies
without migration of the spindle (Verlhac et al., 2000); these investigators also established that the MOS-MAP kinase pathway controls spindle migration by regulating the activity of the actin microfilament network, perhaps through myosin IIA, suggesting a possible signaling pathway of myosin IIA and MOS in regulating MF and the MF-dependent spindle movement in mouse oocytes.
Division of polar bodies
induced by their enlargement in the starfish Asterina pectinifera.
The cleavage furrow was colocated with the position of the extruded polar bodies
at the animal pole.
Each cleavage furrow is numbered in the order of its occurrence, and the polar bodies
(pb and arrow) are visible resting in the first cleavage furrow.
The fertilized egg extrudes the first and second polar bodies
at 8-10 min, and then the zygote begins cleavage at 15-20 min.