Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Biologists find unexpected rapid evolution in Caribbean lizards

15.07.2003


’Lizards gone wild’



Despite social notions of race, human populations around the world are genetically so similar that geneticists find no different sub-species among them. The genetic continuity of human populations is the exception rather than the rule for most animal species, however.

Richard Glor, graduate evolutionary biology student in Arts & Sciences at Washington University in St. Louis, has found extensive genetic differentiation among populations of numerous Anolis lizard species inhabiting single Caribbean islands. While to the naked eye the lizards appear to be uniform, these lizards from the islands of Cuba, Puerto Rico, Hispaniola and Jamaica all show a surprising amount of genetic diversity. Glor goes to the islands and collects lizard samples to study morphology, or body features, and color patterns and then sequences DNA from the different species.


"The levels of differentiation we’re seeing genetically with anoles completely blows away any kind of variation in humans," Glor said. "We’ve found an unanticipated dimension of biodiversity, far greater than ever thought to exist. If you look at DNA in any widespread species, it suggests that several species may actually be present."

The variation that Glor has found startles evolutionary biologists and challenges researchers to understand what is causing the DNA evolution, said Jonathan Losos, Ph.D., Washington University professor of biology, and Glor’s co-adviser.

"What’s so exciting about the variation Rich has discovered is that it’s completely unexpected," said Losos, who has studied Caribbean lizards for more than 15 years. "These lizards have been a model system for understanding evolutionary diversification for 30-plus years,including by a number of famous scientists, yet Rich was the first to discover this. He’s uncovered a whole different layer of speciation and diversification in these species. It’s possible that one group is not just one species but represents maybe six or eight species. At the very least, it shows within species there is a lot of genetic diversity that we had been clueless about beforehand."

Glor’s other adviser is Allan Larson, Ph.D., professor of biology at Washington University. Part of the results of the Anolis study will be published in a forthcoming issue of Evolution.

Glor has found significant geographic differentiation in 11 of 12 widespread Anolis species that he’s analyzed. He has focused on two widely distributed species for each island. Two common ones to all four islands are what are known as a trunk-ground species -- lizards that live at the bottom of tree trunks and forage on the ground – and a trunk-crown species, which live at the treetop and forage in the foliage found there. Glor and Larson’s analyses show that a trunk-crown species in Hispaniola diverged millions of years ago from those in Cuba, and different trunk-crown species on Hispaniola are genetically different from other populations in different regions of the island.

"With each species, there are forms that in one area are greatly different genetically from what we thought was the same species in another area," Glor said.

Glor and his collaborators intend to formulate and test theories on what is driving the genetic variation. Geographic events – the formation of a mountain range, the rising and falling of sea levels, the creation of river valleys – are potential factors. Ecological heterogeneity is another possibility. Species whose ranges extend across a range of different habitats may diverge from one another; for instance, natural selection may drive populations from a dry coastal area on an island to diverge from adjacent populations in wet inland forests. To determine this, the researches will have to analyze the DNA and develop phylogenies –trees that represent evolutionary relationships and incorporate a time factor. This will help them see the patterns of species diversification over time. "What’s so good about anoles is that they are so abundant and what’s so good about these islands is that the same ecologies have evolved independently on all the islands," Glor said.

Another research thrust will be an effort to determine if the size of the island or other factors such as species ecology has an impact on the rate of fragmentation and speciation. Cuba is the largest island, followed by Hispaniola, Jamaica and Puerto Rico. Does speciation occur differently if the playing field is larger?

"Having at least two species from each island and all of the islands varying in size allows us to probe these kinds of questions, " Glor said.

Tony Fitzpatrick | EurekAlert!
Further information:
http://www.wustl.edu/

More articles from Life Sciences:

nachricht Bolstering fat cells offers potential new leukemia treatment
17.10.2017 | McMaster University

nachricht Ocean atmosphere rife with microbes
17.10.2017 | King Abdullah University of Science & Technology (KAUST)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Ocean atmosphere rife with microbes

17.10.2017 | Life Sciences

Neutrons observe vitamin B6-dependent enzyme activity useful for drug development

17.10.2017 | Life Sciences

NASA finds newly formed tropical storm lan over open waters

17.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>