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Index to Creationist Claims,  edited by Mark Isaak,    Copyright © 2005
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Claim CB811:

Evolutionist Gavin de Beer (1971) has shown that homologous structures arise from different, nonhomologous genes, which means that they cannot be derived from common ancestors.

Source:

Kofahl, Robert E., 2003. Handy dandy evolution refuter, chpt. 10. <http://www.parentcompany.com/handy_dandy/hder10.htm>

Response:

  1. It was 1971 when de Beer made his argument. That was before technology for manipulating DNA made it possible to examine genes directly, so de Beer's conclusions (and those of Hardy 1965, making essentially the same argument) were based on indirect evidence. Since then, many similar genes have been found to participate in the development of homologous structures (see, e.g., Carroll 2005).

    Granted, some of the examples raised by de Beer have not yet been explained in detail. For example, some organs considered homologous arise from different layers of embryological tissues. But although such cases are not explained, that does not mean they are unexplainable. We now know that organs can be stimulated to grow in many parts of the body (such as eyes growing on a fly's wings) simply by ensuring that the proper signalling chemicals are present. Thus homologous organs arising from different areas may result simply from mutations in where signalling proteins are expressed.

    The difference in finger development between birds and theropod dinosaurs shows an example of how a small difference in development can lead to a nonobvious difference in adult form.

References:

  1. Carroll, Sean B. 2005. Endless Forms Most Beautiful. New York: W. W. Norton.
  2. de Beer, Gavin. 1971. Homology, an unsolved problem. Oxford Biology Readers, J.J. Head and O.E. Lowenstein, eds., Oxford University Press. Reprinted (abridged) in Ridley, Mark, 1997. Evolution. Oxford University Press, 211-221.
  3. Hardy, Alister. 1965. The Living Stream, New York: Harper & Row, pp. 209-219.

Further Reading:

Carroll, Sean B. 2005. Endless Forms Most Beautiful. New York: W. W. Norton.
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created 2005-5-23