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Genetic Control of Development

Programmed Cell Death: Apoptosis



Development of a multicellular creature requires not only cell differentiation, but in some cases, cell death. Apoptosis helps create the spaces between the fingers, for instance. During brain development, nerve connections are sculpted through the apoptotic death of billions of cells. In C. elegans, exactly 131 cells die by apoptosis.



Cells can be directed to the apoptotic pathway if they fail to receive appropriate signals from their neighbors. In this way, it is thought that cells in the wrong location—a bone cell in the gut, for instance—might be terminated to prevent damage to the organism. The death program itself is carried out within the cell by activation of specific genes that ultimately trigger proteases, which are enzymes that break down cell contents, including the chromosomes.

Richard Robinson

Bibliography

Alberts, Bruce, et al. Molecular Biology of the Cell, 3rd ed. New York: Garland Publishing, 1994.

De Robertis, E. M., G. Oliver, and C. V. Wright. "Homeobox Genes and the Vertebrate Body Plan." Scientific American 263, no. 1 (1990): 46-52.

Gehring, Walter F. Master Control Genes in Development and Evolution. New Haven: Yale University Press, 1998.

Gilbert, Scott F. Developmental Biology, 5th ed. Sunderland, MA: Sinauer Associates, 1997.

Retinoic acid is used as an acne treatment for humans, and must be avoided during pregnancy.

Additional topics

Medicine EncyclopediaGenetics in Medicine - Part 1Genetic Control of Development - The Importance Of Transcription Factors, The European Way And The American Way, Morphogens And Gradients