http://blogs.discovermagazine.com/gnxp/2013/06/the-dog-days-of-evolutionary-genomics/#.UbYTwusXx5i
http://science.nbcnews.com/_news/2013/05/22/18421878-what-prehistoric-dog-burials-tell-us-about-owners?lite=obnetwork
How do you make the perfect sled dog?
http://www.sciencedaily.com/releases/2010/07/100721194758.htm#
ScienceDaily (Sep. 25, 2010) — Over the last few hundred years, Alaskan sled dogs have been bred to haul cargo over Arctic terrain and, more recently, for racing. Now, researchers writing in the open access journal BMC Genetics have identified the contributions different breeds have made to the speed, endurance and work ethic of Alaskan sled dogs.
Heather Huson and Elaine Ostrander, from the National Institutes of Health, Bethesda, USA, worked with a team of researchers to carry out genetic analysis in 199 sled dogs and 681 purebred dogs from 141 different breeds. Huson said, "The Alaskan sled dog comprises several different lineages, optimized for different racing styles -- long or short distance. We sought to identify breed composition profiles associated with expertise at specific tasks, finding that the Alaskan Malamute and Siberian Husky contributions are associated with enhanced endurance; Pointer and Saluki are associated with enhanced speed and the Anatolian Shepherd has a positive influence on work ethic."
The researchers sampled sled dogs from eight kennels, rating them for speed, endurance, and work ethic, using established criteria specified for the distinct racing styles of sprint and distance. These attributes were correlated with genetic information taken from each dog and compared to likely ancestral breeds.
Speaking about the results, Huson said, "The Alaskan sled dog presents a case in which a genetically distinct breed of dog has been developed through the selection and breeding of individuals based solely on their athletic prowess. Interestingly, this continual out-crossing for athletic enhancement has still led to the Alaskan sled dog repeatedly producing its own unique genetic signature. Indeed, the Alaskan sled dog breed proved to be more genetically distinct than breeds of similar heritage such as the Alaskan Malamute and Siberian Husky."
Heather Huson and Elaine Ostrander, from the National Institutes of Health, Bethesda, USA, worked with a team of researchers to carry out genetic analysis in 199 sled dogs and 681 purebred dogs from 141 different breeds. Huson said, "The Alaskan sled dog comprises several different lineages, optimized for different racing styles -- long or short distance. We sought to identify breed composition profiles associated with expertise at specific tasks, finding that the Alaskan Malamute and Siberian Husky contributions are associated with enhanced endurance; Pointer and Saluki are associated with enhanced speed and the Anatolian Shepherd has a positive influence on work ethic."
The researchers sampled sled dogs from eight kennels, rating them for speed, endurance, and work ethic, using established criteria specified for the distinct racing styles of sprint and distance. These attributes were correlated with genetic information taken from each dog and compared to likely ancestral breeds.
Speaking about the results, Huson said, "The Alaskan sled dog presents a case in which a genetically distinct breed of dog has been developed through the selection and breeding of individuals based solely on their athletic prowess. Interestingly, this continual out-crossing for athletic enhancement has still led to the Alaskan sled dog repeatedly producing its own unique genetic signature. Indeed, the Alaskan sled dog breed proved to be more genetically distinct than breeds of similar heritage such as the Alaskan Malamute and Siberian Husky."
Ultra-Endurance Competitors: Lessons From Sled Dogs In The Iditarod
http://www.sciencedaily.com/releases/2008/09/080925072436.htm#
ScienceDaily (Oct. 5, 2008) — Dogs are often called “man’s best friend,” and rightly so. Consider, for example, that they never interrupt us when we talk, are always happy to see us when we arrive home, and provide comfort when we are lovesick. Since dogs became domesticated 15,000 years ago, they have worked with and lived next to humans, which some say may account for the special bond. Each of the 400 breeds and varieties are unique, but only one stands out as the ultra-athlete canine: the racing sled dogs.
Racing sled dogs are best known for their “mushing” each March during the Iditarod Trail Sled Dog Race, the world’s longest sled race. They are the premier ultra-endurance competitors, covering 1,100 miles from Anchorage to Nome, Alaska, sometimes in just nine days. It is unclear how they can keep running, despite heavy blizzards, temperatures as low as –40°F, and winds up to 60 mph. No other animal has been found to come close to the physiological attributes these dogs display.
Dr. Michael Davis has focused on the mysteries of this breed for work for more than a decade. The professor at the Oklahoma State University’s Center for Veterinary Health Sciences will discuss his recent findings entitled, “Metabolic Strategies for Sustained Endurance Exercise: Lessons from the Iditarod.” His presentation is part of the American Physiological Society’s (APS) conference, The Integrative Biology of Exercise V, being held September 24-27, 2008 in Hilton Head, SC.
How Do They Do It? The Exercise Physiology of Sled Dogs
The physiological understandings that Davis and his colleagues have uncovered thus far are extensive. Among their findings is:
Rapid Adaptation to Exercise and Endurance—The most striking feature of these canines is their ability to rapidly adapt to sustained strenuous exercise in 24-48 hours. Conditioned dogs display most of the metabolic changes that are found in human endurance athletes during their first day of exercise, including depletion of muscle energy reserves, increases in stress hormones, evidence of cellular injury (such as to proteins, lipids and DNA), and oxidative stress. However, with subsequent consecutive days of exercise at the same intensity, these changes are reversed. Within four days after exercise begins, the metabolic profile of the dogs returns to where it was before the race began, despite their sustained, strenuous exercise. When human ultra-athletes become fatigued, they stay that way until a period of recovery that may take a full day.
Enormous Aerobic Capacity—Racing sled dogs have enormous aerobic capacity. While the untrained sled dogs have an average aerobic capacity of 175 ml/kg/min VO2 max (ratio of volume of oxygen to body weight per minute), the aerobic capacity of the fully conditioned sled dogs is estimated to be about twice that (300 ml/kg/min).
Using A High-Fat Diet to Fuel Exercise—During periods of racing, sled dogs can burn up to 12,000 kilocalories per day (kcal/day). This means that a 55-pound sled dog will consume the equivalent of 24 McDonald’s Big Macs to fuel their run on any given day. Some of the running dog’s high-fat diet is converted to energy in the liver, and used as fuel in the initial stages of exercise. Preliminary data suggests that this process is a desirable trait intended to efficiently support exercise in the racers. It is worth noting that humans would need 72 Big Macs to fuel the power they need to make a day’s run, assuming their body could absorb and process all the fat contained in the beef.
Next Steps
The mechanisms that make these four-legged athletes premiere in performance is still unknown. Dr. Davis theorizes that it may involve the regulation of extremely thin membranes in the muscle fibers and changes in the cells that are responsible for the body’s energy production. “These are one-of-a-kind athletes. What we learn from them will undoubtedly tell us a lot about human performance as well.”
Racing sled dogs are best known for their “mushing” each March during the Iditarod Trail Sled Dog Race, the world’s longest sled race. They are the premier ultra-endurance competitors, covering 1,100 miles from Anchorage to Nome, Alaska, sometimes in just nine days. It is unclear how they can keep running, despite heavy blizzards, temperatures as low as –40°F, and winds up to 60 mph. No other animal has been found to come close to the physiological attributes these dogs display.
Dr. Michael Davis has focused on the mysteries of this breed for work for more than a decade. The professor at the Oklahoma State University’s Center for Veterinary Health Sciences will discuss his recent findings entitled, “Metabolic Strategies for Sustained Endurance Exercise: Lessons from the Iditarod.” His presentation is part of the American Physiological Society’s (APS) conference, The Integrative Biology of Exercise V, being held September 24-27, 2008 in Hilton Head, SC.
How Do They Do It? The Exercise Physiology of Sled Dogs
The physiological understandings that Davis and his colleagues have uncovered thus far are extensive. Among their findings is:
Rapid Adaptation to Exercise and Endurance—The most striking feature of these canines is their ability to rapidly adapt to sustained strenuous exercise in 24-48 hours. Conditioned dogs display most of the metabolic changes that are found in human endurance athletes during their first day of exercise, including depletion of muscle energy reserves, increases in stress hormones, evidence of cellular injury (such as to proteins, lipids and DNA), and oxidative stress. However, with subsequent consecutive days of exercise at the same intensity, these changes are reversed. Within four days after exercise begins, the metabolic profile of the dogs returns to where it was before the race began, despite their sustained, strenuous exercise. When human ultra-athletes become fatigued, they stay that way until a period of recovery that may take a full day.
Enormous Aerobic Capacity—Racing sled dogs have enormous aerobic capacity. While the untrained sled dogs have an average aerobic capacity of 175 ml/kg/min VO2 max (ratio of volume of oxygen to body weight per minute), the aerobic capacity of the fully conditioned sled dogs is estimated to be about twice that (300 ml/kg/min).
Using A High-Fat Diet to Fuel Exercise—During periods of racing, sled dogs can burn up to 12,000 kilocalories per day (kcal/day). This means that a 55-pound sled dog will consume the equivalent of 24 McDonald’s Big Macs to fuel their run on any given day. Some of the running dog’s high-fat diet is converted to energy in the liver, and used as fuel in the initial stages of exercise. Preliminary data suggests that this process is a desirable trait intended to efficiently support exercise in the racers. It is worth noting that humans would need 72 Big Macs to fuel the power they need to make a day’s run, assuming their body could absorb and process all the fat contained in the beef.
Next Steps
The mechanisms that make these four-legged athletes premiere in performance is still unknown. Dr. Davis theorizes that it may involve the regulation of extremely thin membranes in the muscle fibers and changes in the cells that are responsible for the body’s energy production. “These are one-of-a-kind athletes. What we learn from them will undoubtedly tell us a lot about human performance as well.”