Re: What is the reason of atavism?

Greetings,
You have asked a great question, one that has stirred up quite a bit of 
debate throughout the centuries.

The Harcourt dictionary defines atavism as reappearance of ancestral forms 
or characters in a contemporary organism as a result of a reactivation of 
genes inherited from that ancestral form.  http://www.harcourt.com/dictionary/def/8/5/7/1/857100.html

However, it must be pointed out that genetic atavism is not accepted by 
many scientists, about the only thing that is agreed on is the fact that 
the suject is a controversial one. What has been interpreted as atavism, 
they argue, sometimes is just a particular example of abnormal embryonic 
development or a rare disease. "The fact that a phenotypic trait resembles 
morphological characteristics of primates or other mamals in the 
evolutionary development does not necessarily mean that a "hidden" gene in 
our genome has been de-repressed. This is yet to be to be proven at 
molecular level." 
 http://www.epub.org.br/cm/n09/fastfacts/atavismo_i.htm

You can get some more information regarding atavism by pointing your 
browser to the following sites.

www.biology-online.org/dictionary.asp?Term=Atavism  

www.creationresearch.org/crsq/abstracts/sum29_1.html 

www.infoplease.com/ce6/sci/A0805162.html 

Thanks for taking the time to send in a question to the mad sci network.

June Wingert