But this pairing has no definite starting point. Exact point to point pairing takes place. It is the first vital phenomenon of meiosis. The pairing of homologous chromosomes starts during zygotene. The size of the nucleus increases and homologous chromosomes start getting closer to each other. The chromosomes become shorten and thick so they become visible. Prophase I further consist of the following stages. Meiosis was first discovered and described by German biologist OscarHertwig in sea urchin eggs in 1876. The word meiosis originates from the Greek word ‘meioun’, meaning “to make small,” as it results in a reduction in chromosome number. If there is no meiosis the chromosome number will become double after every generation. Secondly, maintains the number of chromosomes constant in species.
Meiosis is significant for variation produces by crossing over and a random assortment of chromosomes.
The completion result is the production of four haploid cells. Mechanically, the process resembles mitosis, though its outcomes are basically different.
Meiosis II is the second meiotic division, that involves equational partition, or separation of sister chromatids. In meiosis I there is segregation of paired chromosomes and at the end, each daughter cell contains one chromosome (with two chromatids). It occurs in animals at the time of gamete formation and in plants at the time of spore formation. Crossing over – the reshuffling of genetic material (chromosomes) takes place which produces new recombinants and causes genetic diversity. The prophase of meiosis is also significant because it has some important events. The new daughter cells formed are haploid.
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