Metaphase-I###on the metaphase plate
of the spindle bivalents arrangement
Interestingly, CENP-E is involved in the initial alignment of chromosomes at the spindle equator on the metaphase plate
, and therefore, it is required for steady spindle microtubule capture at the kinetochores, which is a critical step in proper chromosome congression during prometaphase.
The meiotic chromosomes were aligned at the metaphase plate
Oocytes were classified as germinal vesicle stage (GV, containing an intact GV), germinal vesicle breakdown stage and metaphase I (GVBD and MI, containing a broken vesicle with the chromatin starting to condense and oocytes with a metaphase plate
, but without a polar body, respectively), metaphase II stage (MII, containing a metaphysical plate and polar body), and degenerated oocyte (oocyte with membrane rupture or without visible chromosomes).
Caption: Figure 5: Metaphase plate
of aspen clone Meshabash: 2n = 38.
In mammalian cells, H3S10P initially occurs within a subset of genes in late G2-interphase cells but subsequently spreads along the chromosomes until completion at prometaphase, after which H3S10P is still evident at the metaphase plate
The developing meiosis I spindle is oriented with the metaphase plate
in the plane of the equatorial cleavage furrows and the poles straddling the mutually perpendicular polar cleavage furrows (Fig.
The process simply involves denucleation of an oocyte (removal of the metaphase plate
) through micro-manipulation.
Over the years, many methods have been developed for preparing somatic chromosomes, and they are generally made up of four stages: first, the seed is germinated and the actively growing root tip is collected; second, a pretreatment using ice cold water for a definite period of time or 8-Hydroxyquinoline, Colchicine, Paradichlorobenzene, or [alpha]-monobromonaphthalene for a definite period of time prior to fixation to inhibit spindle formation, preventing the congression of chromosomes to the metaphase plate
; third is fixation in any of a large range of solutions; fourth, preparation of the root tips by hydrolysis, followed by staining.
Karyotyping study was carried out at Human Genetics Laboratory, Bharathiar University, Coimbatore and every metaphase plate
was found to represent the 45, XO karyotype (Figure 2).
Frequency of chromosomes in the counted metaphase plates
Number of chromosomes in each metaphase plate
94 96.0 98 100.0 Number of metaphase plates
counted 8 6.0 64 2.0 Frequency (%) 10 7.5 80 2.5 DISCUSSION
These comprised precocious migrations to poles in metaphase I and II, non-oriented chromosomes on metaphase plate
in metaphase I (Figure 1B) and II (Figure 1F), laggard chromosomes in anaphase I (Figure 1C and D) and II towards the formation of micronucleus in telophase I (Figure 1E) and II, and microspores in tetrads.