Atavism

For other uses, see Atavism (disambiguation).
Early embryos of various species display some ancestral features, like the tail on this human embryo. These features normally disappear in later development, but it may not happen if the animal has an atavism.[1][2]

In biology, an atavism is a modification of a biological structure whereby an ancestral genetic trait reappears after having been lost through evolutionary change in previous generations.[3] Atavisms can occur in several ways,[4] one of which is when genes for previously existing phenotypic features are preserved in DNA, and these become expressed through a mutation that either knocks out the dominant genes for the new traits or makes the old traits dominate the new one.[3] A number of traits can vary as a result of shortening of the fetal development of a trait (neoteny) or by prolongation of the same. In such a case, a shift in the time a trait is allowed to develop before it is fixed can bring forth an ancestral phenotype.[5] Atavisms are often seen as evidence of evolution.[6]

In social sciences, atavism is the tendency of reversion. For example, people in the modern era reverting to the ways of thinking and acting of a former time.

The word atavism is derived from the Latin atavus—a great-great-great-grandfather or, more generally, an ancestor.

  1. ^ Uthman, Ed (2014). "Tubal pregnancy with embryo". WikiJournal of Medicine. 1 (2). doi:10.15347/wjm/2014.007.
  2. ^ "Multi-cell Organisms". Universe-review.ca. Retrieved 2011-09-29.
  3. ^ a b Brian K. Hall (1984), "Developmental mechanisms underlying the atavisms", Biological Reviews, 59 (1): 89–124, doi:10.1111/j.1469-185x.1984.tb00402.x, PMID 6367843, S2CID 29258934
  4. ^ Tomic, Nenad; Meyer-Rochow, Victor Benno (2011). "Atavisms - medical, genetic, and evolutionary implications". Perspectives in Biology and Medicine. 54 (3): 332–353. doi:10.1353/pbm.2011.0034. PMID 21857125. S2CID 40851098.
  5. ^ Held, L. (2009). Quirks of Human Anatomy, an Evo-Devo Look at the Human Body. Cambridge University Press. ISBN 978-0-521-73233-8.
  6. ^ Cite error: The named reference Briankhall2 was invoked but never defined (see the help page).