Featured Research

from universities, journals, and other organizations

Convergent evolution: New fins evolve repeatedly in teleost fishes

Date:
March 5, 2014
Source:
University of Chicago Medical Center
Summary:
A new study analyzing the origins of the adipose fin, thought by some to be vestigial, finds that these fins arose repeatedly and independently in multiple species -- a striking example of convergent evolution. Adipose fins also appear to have repeatedly and independently evolved skeleton, offering a glimpse into the evolution of vertebrate appendages.

Adipose fin from a specimen at the Field Museum in Chicago.
Credit: Field Museum of Natural History

Though present in more than 6,000 living species of fish, the adipose fin, a small appendage that lies between the dorsal fin and tail, has no clear function and is thought to be vestigial. However, a new study analyzing their origins finds that these fins arose repeatedly and independently in multiple species. In addition, adipose fins appear to have repeatedly and independently evolved a skeleton, offering a glimpse into how new tissue types and structural complexity evolve in vertebrate appendages.

Adipose fins therefore represent a unique example of convergent evolution and new model for exploring the evolution of vertebrate limbs and appendages, report scientists from the University of Chicago in the Proceedings of the Royal Society B on March 5.

"Vertebrates in general have conserved body plans, and new appendages, whether fins or limbs, evolve rarely," said senior author Michael Coates, PhD, chair of the Committee on Evolutionary Biology at the University of Chicago. "Here, we have a natural experiment re-run repeatedly, providing a superb new system in which to explore novelty and change."

Usually small and structurally simple, adipose fins tend to get attention only when they are clipped from farm-raised trout and salmon as a tag. Despite their presence in thousands of fish species, they have been dismissed as a remnant of a once-functional fin. This assumption puzzled Stewart and co-authors, as they saw no evidence of deterioration in adipose fin structure or function in the fossil record.

To study the evolutionary origins of this fin, Coates and lead author Thomas Stewart, graduate student in organismal biology and anatomy at the University of Chicago, turned to a technique known as ancestral-state reconstruction. With co-author W. Leo Smith, PhD, from the Biodiversity Institute at the University of Kansas, they created an evolutionary tree describing the relationships between fish with and without adipose fins, using genetic information from more than 200 ray-finned fish and fossil data from known time points. They then used statistical models to predict when and in what species the adipose fin might have first evolved.

They found that adipose fins originated multiple times, independently, in catfish and other groups of ray-finned fishes -- a striking example of convergent evolution over a vast range of species.

"It's pretty incredible that a structure which is incredibly common could be so misunderstood," Stewart said. "Our finding, that adipose fins have evolved repeatedly, shows that this structure, long assumed to be more-or-less useless, might be very important to some fishes. It's exciting because it opens up new questions."

More than 600 species of fish were studied in the course of this research, including many from the collections of the Field Museum of Natural History in Chicago. This analysis revealed that a number of complex skeletal structures, including spines, plates, fin rays and cartilage discs, evolved independently in the adipose fins of different species. And while studies of the fossil record have suggested that new fins originate in a predictable and repeated manner, adipose fins demonstrate multiple routes to building new appendages.

"These results challenge what was generally thought for how new fins and limbs evolve, and shed new light on ways to explore the full range of vertebrate limb and fin diversity," Stewart notes.

The study was supported by the National Science Foundation and the University of Chicago Division of Biological Sciences.


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. T. A. Stewart, W. L. Smith, M. I. Coates. The origins of adipose fins: an analysis of homoplasy and the serial homology of vertebrate appendages. Proceedings of the Royal Society B: Biological Sciences, 2014; 281 (1781): 20133120 DOI: 10.1098/rspb.2013.3120

Cite This Page:

University of Chicago Medical Center. "Convergent evolution: New fins evolve repeatedly in teleost fishes." ScienceDaily. ScienceDaily, 5 March 2014. <www.sciencedaily.com/releases/2014/03/140305084406.htm>.
University of Chicago Medical Center. (2014, March 5). Convergent evolution: New fins evolve repeatedly in teleost fishes. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2014/03/140305084406.htm
University of Chicago Medical Center. "Convergent evolution: New fins evolve repeatedly in teleost fishes." ScienceDaily. www.sciencedaily.com/releases/2014/03/140305084406.htm (accessed July 24, 2014).

Share This




More Plants & Animals News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. Video provided by Newsy
Powered by NewsLook.com
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. Video provided by Newsy
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