Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Human Embryo and Tails
Name: Karl S.
Status: Other
Age: 20s
Location: N/A
Country: N/A
Date: N/A 


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?



Replies:
All mammals seemingly have gill slits in their very early embryo 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 evolutionary development.

When we look at early fetal development of various animals we see all having gill slits, and tails. Your questions involves very complex answers, but I will address some aspects of what you ask.

Yes, there are people born with tail-like fragments or protrusions of the spinal column, that are removed or reinserted at birth. Though I have seen this in some medical journal, it is so rare that I have had nurses question the whole idea. These "tails" are usually not substantial in structure and certainly do not take on a look of a monkey tail, etc. As a matter of fact, they may not be a tail per sa. I questioned this idea for a long time until I found a friend that was born with a very small protrusions of sorts. Whether it was a tail, is probably a matter of semantics. I do not recall a name for this phenomenon.

If the gill-like slits did remain, the fetus would probably be naturally aborted at a very young embryonic stage. The complex feedback system of embryo development requires a successful step by step process. The human genome project will probably address this or other past characteristics eventually. Humans have a tremendous number of introns (I believe in chromosome 20 alone, there are 164 of these-source "Nature" (Dec. 2001 issue ?).It seems that much of our unused DNA is coded for our evolutionary past, but this is not clear at this writing. It is very clear that we are a product of evolutionary development and we are the threshold of understanding all of this better thanks to DNA analysis studies and related techniques. Keep your eye out for further developments and explanations.

Steve Sample



Click here to return to the Molecular Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory