Chromo example sentences

This stage is characterised by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes.Meiosis is the mechanism by which conservation of specific chromosome number of each species is achieved across generations in sexually reproducing organisms, even though the process, per se, paradoxically, results in reduction of chromosome number by half.Since the number of chromosomes in the parent and progeny cells is the same, it is also called as equational division.Hence, the metaphase is characterised by all the chromosomes coming to lie at the equator with one chromatid of each chromosome connected by its kinetochore to spindle fibres from one pole and its sister chromatid connected by its kinetochore to spindle fibres from the opposite pole (Figureure 2 b).This specialised kind of cell division that reduces the chromosome number by half results in the production of haploid daughter cells.Metaphase I: The bivalent chromosomes align on the equatorial plate (Figureure 3).The complete disintegration of the nuclear envelope marks the start of the second phase of mitosis, hence the chromosomes are spread through the cytoplasm of the cell.Although in many cases the chromosomes do undergo some dispersion, they do not reach the extremely extended state of the interphase nucleus.Crossing over leads to recombination of genetic material on the two chromosomes.In sexual reproduction when the two gametes fuse the chromosome number is restored to the value in the parent.At this stage the chromosomes align at the equator and the microtubules from opposite poles of the spindle get attached to the kinetochores (Figureure 4) of sister chromatids.Each pole receives half the chromosome number of the parent cell.These structures serve as the sites of attachment of spindle fibres (formed by the spindle fibres) to the chromosomes that are moved into position at the centre of the cell.Mitosis thus, is the equational division in which the chromosome number of the parent is conserved in the daughter cell.The M Phase starts with the nuclear division, corresponding to the separation of daughter chromosomes (karyokinesis) and usually ends with division of cytoplasm (cytokinesis).