(Press-News.org) NEW YORK (June 22, 2011) – A new genetic study by a team of Cuban and American researchers confirms that American crocodiles are hybridizing with wild populations of critically endangered Cuban crocodiles, which may cause a population decline of this species found only in the Cuban Archipelago.
Cuban crocodiles and American crocodiles have been confirmed to interbreed in captivity and were suspected to hybridize in the wild. This is the first genetic study that confirms wild hybridization.
The study, which appears in the spring issue of the Journal of Experimental Zoology, is by Yoamel Milián-García of the University of Havana; Miryam Venegas-Anaya of the Smithsonian Tropical Research Institute; Roberto Frias-Soler of the University of Havana; Andrew Crawford of the Smithsonian Tropical Research Institute; Roberto Ramos-Targarona, Roberto Rodríguez-Soberón, and Manuel Alonso-Tabet of Empresa Nacional para la Protección de la Flora y la Fauna; the late John Thorbjarnarson of the Wildlife Conservation Society; Oris I. Sanjur of the Smithsonian Tropical Research Institute; Georgina Espinosa-López of the University of Havana; and Eldredge Bermingham of the Smithsonian Tropical Research Institute.
Known for their leaping ability and aggressive disposition, Cuban crocs are a charismatic and culturally significant species to Cuba. Exact population estimates for the species remain unknown, though scientists believe that a minimum of 3,000 individuals remain in the Zapata swamp. A smaller population exists in the Lanier Swamp on the Island of Youth. The species was extensively hunted from the middle of the 19th century through the 1960s resulting in drastic population declines.
The team collected and analyzed DNA from 89 wild-caught Cuban and American crocodiles in the wild and two samples from crocodiles in zoos.
The genetic data produced an unsuspected result: American crocodiles in Cuba are more closely related to Cuban crocodiles than other American crocodile populations found along mainland Central America. The study found just a 1 percent genetic sequence divergence between Cuban crocodiles and American crocodiles in Cuba yet an 8 percent divergence between American crocodiles in Cuba and other American crocodile populations living in mainland Central America.
This finding indicates that Cuban crocodiles and American crocodiles in Cuba may represent two evolutionary significant units (ESU's) – populations considered distinct for conservation purposes and represent an important component of the evolutionary legacy of the species.
The team collected and analyzed DNA from 89 wild-caught Cuban and American crocodiles in the wild and two samples from crocodiles in zoos.
The authors say that hybridization may be one of the most important threats to Cuban crocodiles, along with illegal hunting and habitat modification. Hybridization can result in both replacement and genetic mixing, and one lineage may cause the extinction of another.
Based on evidence of hybridization between the two species, the authors strongly urge that efforts to avoid anthropogenic causes of hybridization be taken into account for future management plans of Cuban crocodiles.
INFORMATION:
The authors acknowledge the following: Faculty of Biology, University of Havana, Cuba; Marine Research Centre, Havana, Cuba; National Enterprise for the Conservation of Flora and Fauna, Cuba; Smithsonian Tropical Research Institute, Panama, Republic of Panama.
WCS is grateful to the John D. and Catherine T. MacArthur Foundation and the Christopher Reynolds Foundation for supporting critical conservation work in Cuba.
The Wildlife Conservation Society saves wildlife and wild places worldwide. We do so through science, global conservation, education and the management of the world's largest system of urban wildlife parks, led by the flagship Bronx Zoo. Together these activities change attitudes toward nature and help people imagine wildlife and humans living in harmony. WCS is committed to this mission because it is essential to the integrity of life on Earth. Visit: www.wcs.org
Study: Wild Cuban crocodiles hybridize with American crocs
2011-06-23
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
Powerful, intoxicated, anonymous: The paradox of the disinhibited
2011-06-23
Power can lead to great acts of altruism, but also corruptive, unethical behavior. Being intoxicated can lead to a first date, or a bar brawl. And the mask of anonymity can encourage one individual to let a stranger know they have toilet paper stuck to their shoe, whereas another may post salacious photos online. What is the common thread between these three disparate states?
A forthcoming article from the Kellogg School of Management at Northwestern University presents a new model that explains how the diverse domains of power, alcohol intoxication and anonymity produce ...
It's not about the money for long-term care nurses
2011-06-23
Pay plays a relatively small role in a nurse's decision to stay at or leave a job in a nursing home, according to new research from Rice University, the University of Pittsburgh and Baylor College of Medicine. In a comprehensive study of certified nursing assistants, researchers found that attitudinal factors such as job satisfaction and emotional well-being are better predictors of turnover in long-term care facilities.
While previous studies have found high turnover rates -- between 23 and 36 percent -- in the long-term care industry, this new study found that only ...
Economic cost of weather may total $485 billion in US
2011-06-23
Contact: David Hosansky
hosansky@ucar.edu
303-497-8611
Rachael Drummond
rachaeld@ucar.edu
303-497-8604
National Center for Atmospheric Research/University Corporation for Atmospheric Research
Economic cost of weather may total $485 billion in US
BOULDER—Everything has its price, even the weather. New research indicates that routine weather events such as rain and cooler-than-average days can add up to an annual economic impact of as much as $485 billion in the United States.
The study, led by the National Center for Atmospheric Research (NCAR), found that ...
Dietary leucine may fight prediabetes, metabolic syndrome
2011-06-23
BOSTON -- June 22, 2011 -- A study led by researchers at the Joslin Diabetes Center suggests that adding the amino acid leucine to their diets may help those with pre-diabetes or metabolic syndrome.
In an animal study, published in the journal PloS One, mice who had been on a high-fat diet and who also received twice the usual intake of leucine, an amino acid found in protein, showed reductions in their prediabetic conditions with lower blood sugars and less fat in their livers, two of the collection of medical problems associated with insulin resistance that make up ...
College scientist cites enlarged skeletal muscles as reason birds exist
2011-06-23
A developmental biologist at New York Medical College is proposing a new theory of the origin of birds, which traditionally has been thought to be driven by the evolution of flight. Instead, Stuart A. Newman, Ph.D., credits the emergence of enlarged skeletal muscles as the basis for their upright two-leggedness, which led to the opportunity for other adaptive changes like flying or swimming. And it is all based on the loss of a gene that is critical to the ability of other warm-blooded animals to generate heat for survival.
Dr. Newman, a professor of cell biology and ...
Nudging doctors in intensive care unit reduces deaths
2011-06-23
CHICAGO --- Caring for patients in a medical intensive care unit in a hospital and flying a 747 are complicated tasks that require tracking thousands of important details, some of which could get overlooked. That's why the pilot has a checklist and a copilot to make sure nothing slips by.
A new Northwestern Medicine study shows the attending physician in the intensive care unit could use a copilot, too. The mortality rate plummeted 50 percent when the attending physician in the intensive care unit had a checklist – a fairly new concept in medicine -- and a trusted person ...
Sharing wisdom, teacher to teacher
2011-06-23
CAMBRIDGE, Mass. -- How do you teach math students to speak and write effectively about what they do? Crucially, how do you teach their teachers — themselves mathematicians — how to impart and evaluate these skills?
Faced with this problem, a group of instructors in MIT's Department of Mathematics decided that many heads are better than one. They began brainstorming ways to encourage teacher-to-teacher collaboration, bridging educators with similar challenges in different courses and from semester to semester. Now, they've developed a tool they believe will be useful ...
Molecular glue sticks it to cancer
2011-06-23
Imagine dropping dish soap into a sink full of greasy water. What happens? As soon as the soap hits the water, the grease recoils—and retreats to the edges of the sink.
Now, what if the sink was a cancer cell, the globs of grease were cancer-promoting proteins and the dish soap was a potential drug? According to new research from the University of Toronto Mississauga, such a drug could force the proteins to the cell's membrane (a.k.a., the edge of the sink)—and make the cancer cell more vulnerable to chemotherapy.
"This is a totally new approach to cancer therapy," ...
University of Minnesota engineering researchers discover source for generating 'green' electricity
2011-06-23
University of Minnesota engineering researchers in the College of Science and Engineering have recently discovered a new alloy material that converts heat directly into electricity. This revolutionary energy conversion method is in the early stages of development, but it could have wide-sweeping impact on creating environmentally friendly electricity from waste heat sources.
Researchers say the material could potentially be used to capture waste heat from a car's exhaust that would heat the material and produce electricity for charging the battery in a hybrid car. Other ...
Positive results for unprotected left main coronary artery PCI with drug-eluting stents
2011-06-23
Patients with normal left ventricular function who undergo elective unprotected left main coronary artery (ULMCA) percutaneous coronary intervention (PCI) with drug-eluting stents (DES) had favorable outcomes according to new research. Results of the multicenter, retrospective study are reported in the June issue of Catheterization and Cardiovascular Interventions, a journal published by Wiley-Blackwell on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).
For patients with ULMCA disease, coronary artery bypass grafting (CABG), known commonly ...