chiasma
From ZooTerms (Dictionary of Invertebrate Zoology)
Revision as of 23:39, 13 September 2013 by Andreas Plank (Talk | contribs) (1 revision: import_noun-simple)
chiasma (noun; plural chiasmata; Greek chiasma, cross): 1. (Arthropoda: Insecta) A crossing of nerves in the nerve center. a. External (outer): a crossover between the lamina ganglionaris and the medulla externa. b. Internal (inner): a crossover between medula externa and medula internal.
2. An X-shaped chromosome formation seen in meiotic cell division, due to breakage, exchange, and reciprocal fusion of equivalent segments of homologous chromatids.
