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In meiosis 1, it is said that chromosome numbers become halved in the two daughter cells. For example, in a 2n human cell there are 46 chromosomes. During meiosis 1, the cell will undergo interphase and probably the S-phase, where chromosome number becomes duplicated. Now the cell is 4n (i.e. 92 chromosomes). During anaphase 1, 46 chromosome out of 92 would go towards one pole and 46 would go opposite. Thus the resulting two cells will have 46 chromosomes in each. So why should we say that, in meiosis 1, the chromosome number is reduced? I say that S phase shouldn't occur in meiosis 1 but rather it should occur in meiosis 2. Is my reasoning incorrect?

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If you consider sister chromatids to each be a chromosome, meiosis I, rather than halving the chromosome count, separates the homologous chromosomes, which result from sexual reproduction, from one another. Meiosis II then separates the sister chromatids from one another resulting in the final halving of chromosomes.

On the other hand, many if not most biologists don't consider the sister chromatids to be individual chromosomes until they are segregated during meiosis II. In this sense, meiosis I does reduce the chromosome count to half.

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