The stage of prophase in meiosis in which pairing of homologous chromosomes is complete and the paired homologues may twine about each other as they continue to shorten; longitudinal cleavage occurs in each chromosome to form two sister chromatids so that each homologous chromosome pair becomes a set of four intertwined chromatids. SYN: pachynema. [pachy- + G. tainia, band, tape]
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pachy·tene 'pak-i-.tēn n the stage of meiotic prophase which immediately follows the zygotene and in which the paired chromosomes are thickened and visibly divided into chromatids
pachytene adj
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n.
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pachy·tene (pakґe-tēn) [Gr. pachytēs thickness] the third stage of prophase in meiosis I, during which synapsis is complete, forming pairs of homologous chromosomes known as bivalents, and genetic material may be exhanged by crossing over.Medical dictionary. 2011.