title: Symmetry analysis of cell nuclei.
abstract: An algorithm is described that is used to analyze the two-dimensional spatial symmetry of cell nuclei. The method provides two symmetry features: the symmetry index (SI), which estimates the precise spatial symmetry of a given chromatin component, Cn, and the quadrant symmetry index (QSI), which estimates the number of quadrants being occupied by Cn. A previous analysis is used to show that age-related change in Malpighian tubule nuclei from the adult housefly is associated with significant alterations in the spatial symmetry of low-, medium-, and high-density chromatin components (LDC, MDC, HDC). This included a seven-fold increase in the spatial symmetry of HDC and a shift in the symmetry profile (from highest to lowest degree of symmetry) from LDC-MDC-HDC to MDC-LDC-HDC. The increased spatial symmetry of HDC suggests that it occurs at new nuclear sites as the fly ages and that these sites are distributed over approximately 60% of the chromosome population.
authors: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors: J P
authors: JP
authors: Panno
mesh_terms: D000375:Aging; D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure*; D002843:Chromatin / Q000648:ultrastructure; D002988:Cloaca / Q000648:ultrastructure*; D006793:Houseflies / Q000648:ultrastructure*; D008297:Male; D008317:Malpighian Tubules / Q000648:ultrastructure*
chemical_list: D002843:Chromatin