Book Viewer

Short Contents | Full Contents | Other books @ NCBI

| Modern Genetic Analysis Chapter 15. Regulation of Cell Number: Normal and Cancer Cells The Machinery or Programmed Cell Death Genetics In Process 15-2: The nematode Caenorhabditis elegans as a model for programmed cell death Examples of programmed cell death in the development of C. elegans. (a) The nematode's life cycle is shown. (b) A symbolic representation of the cell lineages of 13 cells (the W cell, the P1 cell, and so forth) produced during embryogenesis. The vertical axis is developmental time, beginning with the hatching of the egg into the first larval stage (L1). In each lineage, a vertical blue bar connects the various cell division events (horizontal blue bars). The names of the final cells are shown, such as W.aaa or P1.apa. In several cases, a cell division produces one viable cell and one cell that undergoes apoptosis. A cell that undergoes programmed cell death is indicated with a blue X at the end of a branch of a lineage. In homozygotes for mutations such as ced-3, these cell deaths do not occur.

© 1999 by W. H. Freeman and Company. All rights reserved.