Toward a Biology Worthy of Life > Genes and the Central Fallacy of Evolutionary Theory > Brief excerpt
A project by Stephen L. Talbott

The organism as agent of its own development (3)

As adults we humans embody ourselves in over 10 trillion cells, commonly said to exemplify at least 250 major types. Moreover,

different parts of the body have different subtypes of the major categories of cell type...[Also,] many transient cell types exist in embryonic development...When all these cell types are enumerated, there may be thousands or tens of thousands of kinds representing different stable expression states of the genome, called forth at different times and places in development. (Kirschner and Gerhart 2005, pp. 179-81)

Actually, the emerging story today is even more extreme. Every cell is, to one degree or another, its own cell type. “A growing number of studies investigating cellular processes on the level of single cells revealed large heterogeneity even among genetically identical cells of the same cell type" (Loewer and Lahav 2011). That is, every cell is in one way or another “doing its own thing”. For example, “identical” genomes in “identical” cells can assume altogether different three-dimensional configurations in their respective nuclei, with potentially dramatic implications for divergent gene expression (Krijger and de Laat 2013). Strikingly, however, the cell does its own thing only while heeding the “voice” of the surrounding context. It is disciplined by the needs of its immediate cellular neighborhood as well as those of the entire developing organism in its larger environment.

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