chiasma

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chiasma

(kīăz`mə): see crossing overcrossing over,
process in genetics by which the two chromosomes of a homologous pair exchange equal segments with each other. Crossing over occurs in the first division of meiosis. At that stage each chromosome has replicated into two strands called sister chromatids.
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chiasma

[kī′az·mə]
(anatomy)
A cross-shaped point of intersection of two parts, especially of the optic nerves.
(cell and molecular biology)
The point of junction and fusion between paired chromatids or chromosomes, first seen during diplotene of meiosis.
References in periodicals archive ?
The temporal fibres do not cross at the optic chiasm and project to the ipsilateral side of the visual cortex
In "Spring Pools," it's the self-enclosing figure of chiasm (flowery waters, watery flowers) that tries to hold back the inevitable flow.
Despite the adherence of lesion to the optic chiasm and cavernous sinus in this case, there was no neuro-opthalmological sign detected in physical examination.
The specific juxtaposition of trees and water is best analyzed through Maurice Merleau-Ponty' s phenomenological discussion of chiasm and flesh, to which I turn now.
Indeed, the central image of stanza four--a punning conceit of hands on [clock-]hands--plays ironically around the potential for a reciprocity of touch and touched in a manner that was later to become central to Merleau-Ponty's work in the celebrated "reversibility thesis"--the image of the thinker's two hands touching one another, used to explore the relationship between touch and touching ("The Intertwining-The Chiasm," p.
This is because birds, unlike mammals, have complete decussation of the optic nerve fibers at the optic chiasm to the contralateral area pretectalis.
RADIOLOGIC DIAGNOSIS: Findings are consistent with persistent fetal vasculature syndrome (PFVS) of the right eye associated with microphthalmia, bilateral optic nerve and optic chiasm hypoplasia, and absence of the neurohypophysis.
Research objectives and content The Drosophila irregular chiasm C - roughest (irreC-rst) gene encodes a member of the DM-GRASP subgroup of the neural cell adhesion molecules of the immunoglobulin superfamily.
In both cases, the analysis proposed by Weinman revolves around both the content and the style of The Waves, wherein, in line with the relevance acquired in the author's view by the ideas of identity and language in this novel, the characters' embodiment of the dynamics involved in the unfolding of such concepts (the different relations held with language by the different characters, and their connection with the body for the first chiasm, and the paradoxical merging of individuality and melting together for the second chiasm) are never disconnected from the specific linguistic features of the text.
Also underpinning the argument here is the work of Maurice Merleau-Ponty, who offers "uncontested evidence that one must see or feel in order to think, that every thought known to us occurs to a flesh'" and whose insistence on the figure of "intertwining" or the chiasm, to define embodied experience proves highly suggestive for Knapp's close readings of Spenser and Shakespeare.
There were heterogeneous parenchymal areas and cystic degeneration in the central and the optic chiasm displaced to the cranium.
And that difference is the basis of egoanalysis, for whether awareness of the body as such, or acknowledging the difference or chiasm between 'myself' and an 'other,' a phenomenological account of the "remainder" brings the ego to face the mystery of itself as both in the world and outside it.