pachytene


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pachytene

 [pak´e-tēn]
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 X-shaped chiasmata.

pach·y·tene

(pak'i-tēn),
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.
Synonym(s): pachynema
[pachy- + G. tainia, band, tape]

pachytene

/pachy·tene/ (pak´ĭ-tēn) 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.

pachytene

(păk′ĭ-tēn′)
n.
The third stage of the prophase of meiosis, during which the homologous chromosomes become short and thick and divide into four distinct chromatids.

pachytene

[pak′itēn]
Etymology: Gk, pachy + tainia, ribbon
the third stage in the first meiotic prophase of gametogenesis, in which the paired homologous chromosomes form tetrads. The bivalent pairs become short and thick and intertwine so that four chromatids are visible. See also diakinesis, diplotene, leptotene, zygotene.

pach·y·tene

(pak'i-tēn)
The stage of prophase in meiosis in which pairing of homologous chromosomes is complete; longitudinal cleavage occurs in each chromosome to form two sister chromatids so that each homologous chromosome pair becomes a set of four intertwined chromatids.
[pachy- + G. tainia, band, tape]

pachytene

the stage in prophase 1 of MEIOSIS where the paired HOMOLOGOUS CHROMOSOMES each split into two CHROMATIDS, the whole structure being called a TETRAD.

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.
References in periodicals archive ?
The pachytene index (for calculation see the Methods section) decreased significantly at D7 for CBZ, IPR and CCK.
Effects of dimethyl sulphoxide on early gametogenesis in Caenorhabditis elegans: ultrastructural aberrations and loss of synaptonemal complexes from pachytene nuclei.
In human pachytene spermatocytes, SUMO-1 and another factor that binds to DNA, known as a histone, show discrete patterns.
Primary spermatocytes are abundant, particularly at the pachytene phase, and are therefore thought to be of long duration.
Pachytene [ILLUSTRATION FOR FIGURE 1D OMITTED], diakinesis or metaphase I [ILLUSTRATION FOR FIGURE 1E OMITTED] figures were observed in the meiotic cells.
However, males heterozygous for parental chromosome-2 morphologies showed meiotic pairing difficulties at pachytene and very high levels of nondisjunction (50%-100%) and formation of aneuploid MII cells (Reed et al.
Chromosome micro-dissection and region-specific libraries from pachytene chromosomes of maize (Zea mays L.
An odd number of crossover events (during the pachytene stage of meiosis I) within the inversion segment can lead to two monocentric recombinants with reciprocal duplications/ deficiencies in the gametes, ending up in a risk of inheriting such an imbalance when conception occurs.