Featured Research

from universities, journals, and other organizations

Evolution Of Fins And Limbs Linked With That Of Gills

Date:
March 25, 2009
Source:
University of Chicago Medical Center
Summary:
The genetic toolkit animals use to build fins and limbs is the same one that controls the development of part of the gill skeleton in sharks. Also, the skeleton of any animal appendage is probably patterned by the developmental genetic program that regulates the formation of shark gills. This finding is consistent with an old theory, often discounted in textbooks, that fins and (later) limbs evolved from the gills of an extinct vertebrate.

Gill skeletons. The shark arch gill skeleton (left) shows primitive gill rays that are found only in sharks and other cartilaginous fishes. The gills of other fishes (right) are also arched but lack gill rays. This primitive feature of sharks allowed the researchers to link the developmental genetic program for fins and limbs to the more primitive one for gill rays.
Credit: Image by J. Andrew Gillis, University of Chicago

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, according to a new study.

The research is published in Proceedings of the National Academy of Sciences on March 23, 2009, 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, lead author of the paper and a graduate student in the Department of Organismal Biology and Anatomy at the University of Chicago. "We have pushed back the evolutionary origin of the developmental genetic program that patterns fins and limbs."

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, Gillis added. "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."

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 senior author on the PNAS paper and Professor and 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."

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 appendage—one that's patterned in essentially the same way as fins and limbs."

The deep structural, functional, and regulatory similarities between paired appendages and developing gill rays, as well as the antiquity of gills relative to paired appendages, suggest that the signaling network that is induced by retinoic acid had a patterning function in gills before the origin of vertebrate appendages, the research concludes. And this function has been retained in the gill rays of living cartilaginous fishes.


Story Source:

The above story is based on materials provided by University of Chicago Medical Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Andrew Gillis, Randall D. Dahna, and Neil H. Shubin. Shared developmental mechanisms pattern the vertebrate gill arch and paired fin skeletons. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0810959106

Cite This Page:

University of Chicago Medical Center. "Evolution Of Fins And Limbs Linked With That Of Gills." ScienceDaily. ScienceDaily, 25 March 2009. <www.sciencedaily.com/releases/2009/03/090323212021.htm>.
University of Chicago Medical Center. (2009, March 25). Evolution Of Fins And Limbs Linked With That Of Gills. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2009/03/090323212021.htm
University of Chicago Medical Center. "Evolution Of Fins And Limbs Linked With That Of Gills." ScienceDaily. www.sciencedaily.com/releases/2009/03/090323212021.htm (accessed August 1, 2014).

Share This




More Plants & Animals News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins