Featured Research

from universities, journals, and other organizations

Oceanic Invasions Across Darwin's Impassable Barrier

Date:
July 6, 2006
Source:
Smithsonian Tropical Research Institute
Summary:
Reef fish share genetic connections across what Darwin termed an "impassable barrier," 5000km of deep ocean separating the eastern and central Pacific, according to a report by Smithsonian scientists in the Proceedings of the Royal Society B.

Cantherhines dumerilii.
Credit: D.R. Robertson

Reef fish share genetic connections across what Darwin termed an 'impassable barrier', 5000km of deep ocean separating the eastern and central Pacific, according to a report by Smithsonian scientists in the Proceedings of the Royal Society B.

By sequencing mitochondrial DNA from 20 morphospecies of fairly sedentary shore fish on both sides of the divide, the study confirms close relationships between populations of the same fish species across the barrier and indicates that genes move in both directions across the barrier.

Luck affects who makes it across and when

"We didn't find genetic evidence for any oceanographic or geological events that separated populations such as a major change in currents or the sinking of an underwater platform that could have served as a stepping stone," Lessios points out. "If that were the case, several species would have shown coincident times of separation." Instead, the researchers consider that fish larvae cross the barrier often enough to maintain genetic connections, but in a very haphazard and infrequent fashion, such that speciation did occur in most cases, but was prevented from happening in others.

Two-way gene flow

Conventional wisdom held that there was little larval movement from West to East and no movement from East to West across the divide until a recent study by co-author Robertson et al. indicated that about 20% of transpacific fish invaded from East to West. "The current study provides more meat for that barbeque. If you look at westward currents, they look as good as or better then eastward currents for moving larvae between populations. People were just focused on eastward movement because El Nino currents go that way," according to Robertson.

Whereas this study was able to rule out the idea that a vicariance event separated these species long ago, all of the alternative hypotheses to explain the presence of related species in the Eastern and Central Pacific still seem to be valid. Several of the species are likely to have been separated long ago and continue to diverge. Others presumably were separated more recently. And gene flow in both directions has occurred. Therefore, low level dispersal should be considered as an important factor in breaching the East Pacific Barrier.

The Smithsonian Tropical Research Institute (STRI), a unit of the Smithsonian Institution, headquartered in Panama City, Panama, furthers our understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems.

 


Story Source:

The above story is based on materials provided by Smithsonian Tropical Research Institute. Note: Materials may be edited for content and length.


Cite This Page:

Smithsonian Tropical Research Institute. "Oceanic Invasions Across Darwin's Impassable Barrier." ScienceDaily. ScienceDaily, 6 July 2006. <www.sciencedaily.com/releases/2006/07/060705184842.htm>.
Smithsonian Tropical Research Institute. (2006, July 6). Oceanic Invasions Across Darwin's Impassable Barrier. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2006/07/060705184842.htm
Smithsonian Tropical Research Institute. "Oceanic Invasions Across Darwin's Impassable Barrier." ScienceDaily. www.sciencedaily.com/releases/2006/07/060705184842.htm (accessed April 16, 2014).

Share This



More Plants & Animals News

Wednesday, April 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Change of Diet Helps Crocodile Business

Change of Diet Helps Crocodile Business

Reuters - Business Video Online (Apr. 16, 2014) — Crocodile farming has been a challenge in Zimbabwe in recent years do the economic collapse and the financial crisis. But as Ciara Sutton reports one of Europe's biggest suppliers of skins to the luxury market has come up with an unusual survival strategy - vegetarian food. Video provided by Reuters
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) — A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Couples Who Sleep Less Than An Inch Apart Might Be Happiest

Couples Who Sleep Less Than An Inch Apart Might Be Happiest

Newsy (Apr. 16, 2014) — A new study by British researchers suggests couples' sleeping positions might reflect their happiness. Video provided by Newsy
Powered by NewsLook.com
Passengers Abuzz After Plane Hits Swarm of Bees

Passengers Abuzz After Plane Hits Swarm of Bees

AP (Apr. 16, 2014) — An Allegiant Airlines plane from Las Vegas to Duluth, Minnesota turned around shortly after take-off, after a swarm of bees clouded the windshield and got sucked into the engines. (April 16) 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