pachytene

pachytene /pachy·tene/ (pak´i-ten) in the prophase of meiosis, the stage following zygotene during which the chromosomes shorten, thicken, and separate into two sister chromatids joined at their centromeres. Paired homologous chromosomes, which were joined by synapsis, now form a tetrad of four chromatids. Where crossing over has occurred between nonsister chromatids, they are joined by X-shaped chiasmata.

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pach·y·tene (pk-tn)

n.

The third stage of the prophase of meiosis during which the homologous chromosomes become short and thick and divide into four distinct chromatids.

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pachytene

in prophase of meiosis, the stage following zygotene during which the chromosomes shorten, thicken and separate into two sister chromatids joined at their centromeres. Paired homologous chromosomes, which were joined by synapsis, now form a tetrad of four chromatids. Where crossing over has occurred between nonsister chromatids, they are joined by Y-shaped chiasmata.