Evolution of fins and limbs linked with that of gillsMarch 24th, 2009 - 12:15 pm ICT by ANI
Washington, March 24 (ANI): A new research has suggested the genetic toolkit that animals use to build fins and limbs is the same genetic toolkit that controls the development of part of the gill skeleton in sharks.
The research was conducted by Andrew Gillis and Neil Shubin of the University of Chicago, and Randall Dahn of Mount Desert Island Biological Laboratory.
In fact, the skeleton of any appendage off the body of an animal is probably patterned by the developmental genetic program that we have traced back to formation of gills in sharks, said Andrew Gillis.
We have pushed back the evolutionary origin of the developmental genetic program that patterns fins and limbs, he added.
This new finding is consistent with an old theory, often discounted in science textbooks, that fins and (later) limbs evolved from the gills of an extinct vertebrate.
A dearth of fossils prevents us from definitely concluding that fins evolved from gills. Nevertheless, this research shows that the genetic architecture of gills, fins and limbs is the same, said Gillis.
The research builds on the breakthrough discovery of the fossil Tiktaalik, a fish with legs, by Neil Shubin and his colleagues in 2006.
This is another example of how evolution uses common developmental programs to pattern different anatomical structures, said Shubin, who is the Associate Dean of Organismal and Evolutionary Biology at the University of Chicago.
In this case, shared developmental mechanisms pattern the skeletons of vertebrate gill arches and paired fins, he added.
The research also showed for the first time that the gill arch skeleton of embryonic skates (a living relative of sharks that has gill rays) responds to treatment with the vitamin A derivative retinoic acid in the same way a limb or fin skeleton does, by making a mirror image duplicate of the structure as the embryo develops.
According to the researchers, the genetic circuitry that patterns paired appendages (arms, legs and fins) has a deep evolutionary origin that actually predates the origin of paired appendages themselves.
These findings suggest that when paired appendages appeared, the mechanism used to pattern the skeleton was co-opted from the gills, Gillis said.
Perhaps we should think of shark gills as another type of vertebrate appendageone thats patterned in essentially the same way as fins and limbs, he added. (ANI)
- Research suggests humans evolved from prehistoric sharks - Jun 14, 2012
- Humans evolved from fish into two-legged species - Oct 07, 2011
- Shark fossil hunt sheds new light into vertebrate evolution - Jan 02, 2010
- Gene loss could help explain evolution of limbs from fins - Jun 24, 2010
- Fish were the first to have sex for fun, fossils suggest - Oct 12, 2010
- Fossil represents evolutionary transition from fish to land animals - Oct 16, 2008
- Fish could explain how we developed arms, legs - Aug 08, 2012
- Deadly toxins in shark fin soup linked to Alzheimer's - Feb 24, 2012
- Gene may explain how leopards got its spots - Feb 25, 2011
- Ancient mass extinction of fish paved way for modern vertebrates - May 18, 2010
- Genetic clues to evolution of jaws in vertebrates discovered - Sep 25, 2010
- Fossil footprints stretch history of our ancestors - Jan 09, 2010
- Dinosaur fish had sex 380 million years ago - Jul 16, 2009
- 500m-year-old squid-like carnivore no more a mystery - May 27, 2010
- Earliest backboned land animals had different life histories - Apr 21, 2009
Tags: anatomical structures, appendage, associate dean, biological laboratory, breakthrough discovery, dahn, derivative retinoic acid, developmental mechanisms, evolutionary biology, evolutionary origin, genetic architecture, genetic circuitry, genetic program, gill arch, gill arches, gillis, mirror image, mount desert island, neil shubin, science textbooks