Ask A Scientist© Molecular Biology Archive

name         Karl S.
age          20s
Question -   I read the following question and answer from your web
site, and I understand the explaination of recapitulating phylogeny,
but is it actually possible for babies to be born with either
something resembling "gill slits" or a "tail"?  Possibly flaps of
skin or an elongated tail bone?
Question -  Is it true that babies can be born with a
congenital throwback i.e. born with fish gill/s and if so
what is it called?
All mammals have gill slits in their very early fetal
development. We call this ontogeny recapitulating phylogeny..where the
development of the individual goes through some of the characteristics of the
animals lower in the evolutional development.
When we look at early fetal development of various animals
we see all having gill slits, and tails.

Yes ... almost anything is possible.  Although usually not for the reasons
that one might expect. What congenital anomalies of development show are
often related to the time of delivery/parturition.

PF
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