Endangered river turtle's genes reveal ancient influence of Maya Indians

ScienceDaily (July 22, 2011) — A genetic study focusing on the Central American river turtle (Dermatemys mawii) recently turned up surprising results for a team of Smithsonian scientists involved in the conservation of this critically endangered species. Small tissue samples collected from 238 wild turtles at 15 different locations across their range in Southern Mexico, Belize and Guatemala revealed a "surprising lack" of genetic structure, the scientists write in a recent paper in the journal Conservation Genetics.See Also:Plants & AnimalsFrogs and ReptilesEndangered AnimalsEarth & ClimateWaterFloodsFossils & RuinsFossilsAncient CivilizationsReferenceSea turtleSnapping turtleMarine conservationTurtle

The turtles, which are entirely aquatic, represent populations from three different river basins that are geographically isolated by significant distance and high mountain chains.

"We were expecting to find a different genetic lineage in each drainage basin," explains the paper's main author Gracia González-Porter of the Center for Conservation and Evolutionary Genetics at the Smithsonian Conservation Biology Institute. "Instead, we found the mixing of lineages. It was all over the place." Despite appearing isolated, the genetic data showed the different turtle populations had been in close contact for years.

"But how?" the researchers wondered.

The best possible explanation, González-Porter and her colleagues say, is that for centuries humans have been bringing them together. The turtles have been used as food, in trade and in rituals for millennia, widely transported and customarily kept in holding ponds till they were needed.

"For centuries, this species has been part of the diet of the Mayans and other indigenous people who lived in its historic distribution range," the scientists point out in their paper. "D. mawii was a very important source of animal protein for the ancient Mayans of the Peten (Preclassic period 800-400 B.C.)…. And it is possible that these turtles were part of the diet of the Olmec culture more than 3,000 years ago."

One specimen of D. mawii was found in an ancient Teotihuacan burial site in Mexico, a spot located more than 186 miles from the known range of this turtle, the researchers say. An ancient sculpture of a Central American river turtle at the National Museum of Anthropology in Mexico City was found in the Basin of Mexico, more than 217 miles from the turtle's range.

"The Central American River turtle is tame and resilient," González-Porter explains, "which makes it easy to transport. Their shells give them lots of protection. People don't have refrigeration so they put the turtles in ponds in their back yards."

During the rainy season in the tropics, the water flows are huge, she says. Rivers and ponds flood, captive turtles escape and mix with the local turtles.

This ancient practice still persists today. In Guatemala, Central American river turtles are kept in medium-sized ponds where they can be easily captured when needed. Similarly, in the State of Tabasco, Mexico, captured turtles are kept in rustic ponds and raised until they are either consumed or sold.

The genetic analysis of the Central American River turtle was initiated because these animals are critically endangered, González-Porter says.

They are the last surviving species of the giant river turtles of the family Dermatemydidae. D. mawii is currently the most endangered turtle species in Central America. A recent increase in the commercial demand for its meat has pushed it to the brink of extinction -- 2.2 pounds of their meat can fetch $100. Most local populations have disappeared and this turtle is now largely restricted to remote areas that are inaccessible to humans.

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Brain autopsies of four former football players reveal not all get chronic traumatic encephalopathy

ScienceDaily (July 26, 2011) — Preliminary results from the first four brains donated to the Canadian Sports Concussion Project at the Krembil Neuroscience Centre, TorontoWesternHospital, reveal that two of the four former Canadian Football League (CFL) players suffered from a brain disease known as Chronic Traumatic Encephalopathy (CTE), while two did not show signs of CTE.See Also:Health & MedicineChronic IllnessHealthy AgingDiseases and ConditionsMind & BrainBrain InjuryDisorders and SyndromesIntelligenceReferenceDementia with Lewy bodiesDementiaHead injuryNeurology

Bobby Kuntz, a former Toronto Argonaut and Hamilton Tiger-Cat and Jay Roberts, an Ottawa Roughrider both had a history of repeated concussions during their careers and showed the characteristic signs of CTE, an abnormal build-up of a protein called Tau in the brain, and other degenerative changes.

CTE can result in memory impairment, emotional instability, erratic behavior, depression, and problems with impulse control. CTE may eventually progress to full-blown dementia. Dr. Hazrati is very clear, however, to emphasize that the precise relationship between concussions and neurodegeneration remains to be demonstrated by future research.

Peter Ribbins, a former Winnipeg Blue Bomber, passed away in December 2010, at age 63 of Parkinson's disease. Autopsy results show he did not have signs of CTE. Tony Proudfoot, anall-star defensive back for the Montreal Alouettes, died at age 61 in 2011 of Lou Gehrig's disease (a neurodegenerative condition also known as ALS). Although a connection between ALS and repeated head trauma is being researched, Proudfoot did not have signs of CTE. Both of these players were in the league at a time when it was common to spear tackle with the crown of the head. According to the Canadian Football League Alumni Association (CFLAA), Proudfoot experienced repeated head trauma as a hard-hitting defensive back throughout his 12 seasons in the league.

Kuntz passed away in February 2011 at age 79 after a long battle with Parkinson's Disease and diffuse Lewy body disease, a condition that overlaps with Parkinson's and Alzheimer's. Roberts, 67, who died in October 2010, suffered from dementia and lung cancer. The autopsies were performed by Dr. Lili-Naz Hazrati, a neuropathologist in the Laboratory Medicine Program at the University Health Network.

"While both of these men appeared to have pathological signs of CTE, they also suffered from other serious neurological and vascular related diseases," said Dr. Hazrati. "Right now we have more questions than answers about the relationship between repeated concussions and late brain degeneration. For example, we are still trying to understand why these two players acquired CTE and the other two did not."

Mary Kuntz, wife of the late Bobby Kuntz, donated his brain to the Canadian Sports Concussion Project at the Krembil Neuroscience Centre and believes the more players who donate their brains, the better the chances of helping future athletes.

"We've always had questions about Bob's health, because there were so many conflicting medical opinions," said Mary Kuntz. "We knew there must have been some effect from all of the concussions over the years, and this was an affirmation that concussions did have a part in his health problems.

"Young players should know the risks of concussions. When you are young, you can't believe what can happen to you when you are older, but we have lived though it. What is good about this study is that there will be more evidence and information for players."

"We were very happy to be involved in this and it has brought us a sense of closure."

The Canadian Sports Concussion Project at the Krembil Neuroscience Centre is organized by a team of concussion experts including Dr. Charles Tator and Dr. Richard Wennberg and scientists from several other Canadian institutions. The focus of the project is to further our understanding of how concussions affect the brain.

"There are still so many unanswered questions surrounding concussion and the long-term consequences of repeated head injuries," said Dr. Tator. "We are trying to determine why some athletes in contact sports develop CTE and others don't, as well as how many concussions lead to the onset of this degenerative brain disease. Also, we need to develop tests to detect this condition at an early stage and to discover treatments."

According to Jed Roberts, son of Jay Roberts, he and his sisters began noticing early signs of their father's memory decline when he starting repeating stories, but insisting he had never told them. "My dad had numerous concussions, although they were undocumented, and I think he knew there was something was wrong, which is why he wanted to help find answers that would hopefully protect future football players," said Jed, a former CFL player with the Edmonton Eskimos. "I think it is really important that we create awareness around this issue, so that players can live healthy, productive lives beyond the game."

Leo Ezerins, former CFL player and current Executive Director of the CFLAA is a member of the Project Team. It has been through the joint efforts of the CFLAA and the research team that these four donations were made possible.

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Parasites help reveal new ecological rules: Animal species large and small follow same rule for how common they are in ecosystems

ScienceDaily (July 21, 2011) — Scientists at UC Santa Barbara and other institutions say their new research is expected to profoundly affect the field of ecology and can assist the management of ecosystems, including forests, lakes, and oceans. And it's all because of parasites.See Also:Plants & AnimalsZoologyEcology ResearchNatureEarth & ClimateEcologyRainforestsEcosystemsReferenceEcological nicheFood chainProtozoaTrophic level

The research, published this week in the journal Science, includes parasites in a comprehensive study of ecosystems. By doing so, the scientists say they have revealed new ecological rules.

"The major finding of our research is that all types of animals -- parasites or otherwise -- appear to follow exactly the same rule for how common they are," said Ryan Hechinger, lead author and associate research biologist with the Marine Science Institute at UCSB.

"This includes birds, fishes, insects, crabs, clams, and all the parasites that live inside and on them," said Hechinger. "They all seem to follow the same rule. And the rule is simple. You can predict how common an animal is just by knowing how big an individual is and how high in the food chain it is."

Hechinger explained that body size is important because it determines how much food an animal needs. A given amount of food supports fewer big animals than small animals because each big animal needs more food. The food chain is important because the higher an animal is in the food chain, the less food there is and, therefore, the less common that species is.

According to the scientists, they did something no one has previously done: They went into an ecosystem and paid attention to parasites, treating them as equal players with other animals. "We realized that despite being small, parasites feed high up the food chain and might break the rule that smaller animals are more common," said co-author Kevin Lafferty, ecologist with the U.S. Geological Survey at UCSB.

The data were collected at three estuaries in Southern California and Baja California. The researchers counted and weighed parasites and other animals before documenting that parasites were indeed less common than other small animals.

"Paying attention to parasites was central to the study," said co-author Armand Kuris, professor of zoology at UCSB. "Parasites are at least half of all biodiversity. And they are different in some very basic ways than other life forms. However, ecological science usually ignores them. How can we possibly understand how life works if we don't look at half of the species -- the parasites?

"Considering parasites helped us find the right theory, see the true patterns in nature, and better test the theory," Kuris said. "In addition to body size, the general rule for animal abundance must factor in the food chain and let both small and large animals be top consumers."

The scientists also discovered a second general rule: that the amount of biomass produced by a population does not depend on the body size of the animals in the population, or on what type of animal -- bird, fish, crab, or parasite.

"If this rule is general, it means an aphid population can produce the same amount of biomass as a deer population," said Lafferty. "Furthermore, tapeworms that feed on the deer population produce less biomass than the deer, but can produce the same as a mountain lion population that also feeds on the deer."

"Predicting animal abundance is one of the most basic and useful things ecological science can provide for management and basic research," said Hechinger. "This simple rule helps with that because it may apply to all life forms and can easily be applied to complex ecosystems in the real world."

Additional co-authors include Andy Dobson of Princeton University and the Santa Fe Institute, and James Brown of the University of New Mexico.

The research was partly funded by the joint National Science Foundation-National Institutes of Health's Ecology of Infectious Diseases program.

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