A genetic study by Peter Savolainen, a researcher in evolutionary genetics at KTH Royal Institute of Technology in Stockholm, has found that dog breeds from North and South America have Asian ancestry.
The Chihuahua definitely has Mexican heritage
The native breeds have 30 percent or less modern replacement by European dogs. It had been thought, prior to this study, that when Europeans settled in the American continent their dog breeds successively replaced the genetics of the native breeds.
Savolainen’s research group, in cooperation with colleagues in Portugal, compared mitochondrial DNA from Asian and European dogs, ancient American archaeological samples, and American dog breeds, including Chihuahuas, Peruvian hairless dogs and Arctic sled dogs.
They traced the American dogs’ ancestry back to East Asian and Siberian dogs, and also found direct relations between ancient American dogs and modern breeds.
The research confirmed conclusively that the modern day Chihuahua has Mexican roots. The breed shares a DNA type uniquely with Mexican pre-Columbian samples.
The team also analysed stray dogs, confirming them generally to be runaway European dogs; but in Mexico and Bolivia they identified populations with high proportions of indigenous ancestry.
Dog hair is used to diagnose hyperadrenocorticism (Photo: Ouschan/Vetmeduni Vienna)
Many dogs suffer from hyperadrenocorticism, more commonly known as Cushing’s Disease. The disease is characterised by excessive amounts of hormones known as glucocorticoids that are produced by the adrenal glands. The disease is more common in older dogs. Most cases result from a tumour in the pituitary gland but some are caused by tumours in the adrenal glands.
The symptoms of a dog with Cushing’s Disease often ‘creep up’ on the owner and vet. Common symptoms include excessive drinking (and urination) and overeating, leading to a pot-bellied appearance, as well as with loss of hair. Since all of these symptoms can stem from a number of disorders, it is difficult to be certain. The methods traditionally used to diagnose the disease are complicated and costly and usually give information about the hormone concentrations at the time a sample is taken. Since most dogs are stressed by veterinary examinations, their hormone levels will peak because of the stress – making it difficult to rely on the analytical results.
Researcher Claudia Ouschan and colleagues at the University of Veterinary Medicine, Vienna decided to look for a way to monitor the long-term levels of glucocorticoids in dog hair that would also offer a diagnostic option that was less stressful to the dogs. She compared the levels of cortisol, corticosterone and cortisone in the hair of twelve dogs with hyperadrenocorticism and ten healthy dogs. The results were striking: all three hormones were found at far higher levels in the hair of dogs with Cushing’s Disease than in the control group, with the increase in cortisol particularly pronounced.
She concludes, ‘we think it (our findings) have real promise for use as a rapid and non-invasive method to diagnose hyperadrenocorticism.’
Her research has been published in the journal Veterinary Dermatology.
I’m ‘on the record’ that I don’t support breed specific legislation (BSL) and I consider it one of New Zealand’s great shames that it has adopted such laws (just one of the issues I raised when I submitted to the review of the Animal Welfare Act).
Breed specific legislation doesn’t work because, in part, these laws rely on visual identification of breeds. If a dog is identified as one of the banned or dangerous breeds, it can (literally) be ‘all over, Rover.’
There’s scientific research that shows why visual identification is a fatal flaw in BSL. Some of this research has been conducted by Dr Victoria Lea Voith who is based at the Western University of Health Sciences, College of Veterinary Medicine.
In 2009, Voith and her colleagues published results of a study comparing visual identification of dog breed with DNA results. They showed that there was a very low accuracy rate when visual identifications were verified with DNA. The research team concluded:
There is little correlation between dog adoption agencies’ identification of probable breed composition with the identification of breeds by DNA analysis
Further evaluation of the reliability and validity of visual dog breed identification is warranted
Justification of current public and private policies pertaining to breed specific regulations should be reviewed
This year (2013), Voith and her colleagues published another paper entitled “Comparison of Visual and DNA Breed Identification of Dogs and Inter-Observer Reliability” Since their previous paper was based on the identification of breed by a single person, the research team wanted to see if the success rate of breed identification improved when multiple people were involved. The research team presented one-minute video clips of the same 20 dogs to over 900 people who were engaged in dog-related professions or services.
For 14 of the dogs, fewer than 50% of the respondents visually identified breeds of dogs that matched DNA identification. For only 7 of the dogs was there agreement among more than 50% of the respondents regarding the most predominant breed of a mixed breed. In 3 of those 7 cases, the visual identification did not match the DNA analysis.
This time, the research team concluded:
This study reveals large disparities between visual and DNA breed identification as well as differences among peoples’ visual identifications of dogs. These discrepancies raise questions concerning the accuracy of databases which supply demographic data on dog breeds for publications such as public health reports, articles on canine behavior, and the rationale for public and private restrictions pertaining to dog breeds.
Dr Voith explains her research in this YouTube video:
If you still want to know more about this issue, you can visit the Breed Identification page of the National Canine Research Council. On this page, you can download color posters that further explain the problems associated with visual identification of breeds.
The structural abnormalities in the brains of dogs suffering from canine compulsive disorder (CCD) are similar to the abnormalities found in humans suffering from obsessive compulsive disorder (OCD) according to new research.
A collaboration between veterinarians at the Cummings School of Veterinary Medicine at Tufts University and researchers at the McLean Imaging Center at McLean Hospital, in Belmont, Massachusetts have published their findings in Progress in Neuro-Psychopharmacology & Biological Psychiatry.
The study involved 16 Doberman Pinschers, 8 with CCD and 8 without. Dogs with CCD engage in repetitious and destructive behaviors such as flank- and blanket-sucking, tail chasing, and chewing, whereas people with OCD tend to have repetitious behaviors that interfere with their daily life.
Here’s a video of a German Shepherd with CCD engaging in a circling behavior:
“While the study sample was small and further research is needed, the results further validate that dogs with CCD can provide insight and understanding into anxiety disorders that affect people. Dogs exhibit the same behavioral characteristics, respond to the same medication, have a genetic basis to the disorder, and we now know have the same structural brain abnormalities as people with OCD,” said Nicholas Dodman, BVMS, DACVB, professor of clinical sciences at the Cummings School of Veterinary Medicine at Tufts University.
It should be noted that the research also provides insight into dog behavior and management. In some cases, a dog labelled as ‘bad’ or ‘destructive’ may actually have a biological basis for their problems.
New research from the University of Georgia suggests that neutering procedures could add to the length of a dog’s life and alter the risk of specific causes of death.
Looking at a sample of 40,139 death records from the Veterinary Medical Database from 1984-2004, researchers determined the average age at death for intact dogs—dogs that had not been spayed or neutered—was 7.9 years versus 9.4 years for sterilized dogs.
These figures may seem low considering how many pets live much longer, but the researchers noted that the life spans would be lower than those seen more widely because their sample was taken from dogs seen at teaching hospitals (so other things would have been going on and the study population would have had more sick animals).
The researchers stand behind their results – that the difference between neutered and intact is real.
Dr. Kate Creevy, an assistant professor of internal medicine at the College of Veterinary Medicine. “The question that raises is why would you die younger if you have offspring?”
For the first time, researchers have been able to measure costs of reproduction in terms of the actual causes of death, finding that the causes of death differed between sterilized and intact dogs. Dogs who had undergone a gonadectomy (a spay or castration) were more likely to die from cancer or autoimmune diseases. Those in the sample who still had functional reproduction systems at death were more likely to die from infectious disease and trauma.
“Intact dogs are still dying from cancer; it is just a more common cause of death for those that are sterilized,” said Jessica Hoffman, a UGA doctoral candidate in the Franklin College of Arts of Sciences who co-authored the study.
Some of the reproductive hormones, particularly progesterone and testosterone, she said, could suppress the immune system, explaining why there is an increased risk of infection among dogs that have been sterilized.
The full journal article, published in PLoS One, can be viewed here.
A University of Illinois research team led by Professor Kelly Swanson has published research which describes how nutrients and biological compounds in foods can affect gene expression in animals.
The research will help to understand the underlying reasons for obesity in pets. Professor Swanson explains that obesity has its roots in the domestication of dogs. Because dogs no longer hunt or compete for their food and are speyed or neutered (so not having to mate), the typical dog has much smaller energy requirements than its forefathers.
The research team explains that when more energy (food) is consumed than is required, it is stored as fat in the adipose tissue (fat tissue). Adipose tissue secretes more than 50 substances known as adipokines, which are cell-signaling molecules that are involved in metabolism, immunity and inflammation.
In obese dogs, levels of the adipokine leptin increases while the levels of the adipokine adiponectin decreases.
The researchers aim to study obesity at the molecular level, so they can help to prevent it happening.
Researchers from the University of Bristol School of Veterinary Sciences have investigated the occurrence of anxiety from exposure to noise and the risk factors for these behaviours.
Almost half of the owners who were interviewed reported that their dog showed at least one behavioural sign typical of fear when exposed to noises such as fireworks, thunder and gunshots, even though only a quarter had reported their dog as ‘fearful’ of noises.
This suggests that while owners are aware of their pet’s behavioural response when exposed to a loud noise, they do not necessarily recognise this as being indicative of fear or anxiety.
And when owners don’t recognise anxiety, they don’t seek help for it. Less than one-third of dog owners sought help for their dog’s anxiety.
The most commonly reported behavioural signs were vocalising, trembling/shaking, hiding, and seeking the comfort of people. Since trembling and shaking are human responses to fear and anxiety, it seems like these behaviours were recognised more easily.
Other behavioural signs, such as decreased activity or salivation, did not appear to be recognised as often (possibly resulting in under-reporting). Also, signs of urination, salivation and destruction may make owners disappointed or angry, and this may over-ride the association with anxiety.
Risk of anxiety induced by noise increased with age and origin. If dogs lived with the owner who bred them, they had a reduced risk compared to dogs purchased from the breeder by a second owner. The researchers suggest a dog’s early life experience is an important factor in the development of fear response.
The researchers recommend there is a need for veterinarians to increase awareness among the general dog owning public about anxiety induced by loud noises and to direct them towards appropriate sources of help. (By the way, I’ve worked with dogs using a programme of de-sensitization and relaxation techniques to help treat anxiety).
Research published in the journal of Animal Cognition shows that dogs pick out faces of other dogs, irrespective of breeds, among other faces. They can group them into a category of their own and do so using only visual cues.
The authors of the study have concluded “The fact that dogs are able to recognize their own species visually, and that they have great olfactory discriminative capacities, insures that social behavior and mating between different breeds is still potentially possible. Although humans have stretched the Canis familiaris species to its morphological limits, its biological entity has been preserved.”
Apparatus. a, b The dog sits in front of the experimenter, on a line between the 2 screens. c When hearing an order, the dog expressed his choice by going to a given screen and putting his paw in front of the chosen image. (Credit: Image courtesy of Springer Science+Business Media)
The authors of the research explored whether the large range of diversity in the size and shape of dogs presented a ‘cognitive challenge’ to dogs trying to recognize their species, when confronted with other species.
On a computer screen, the researchers showed nine pet dogs pictures of faces from various dog breeds and cross-breeds, and simultaneously faces of other animal species, including human faces. They exposed the dogs to diverse stimuli: images of dog faces; images of non-dog species from 40 different species, including domestic and wild animals; and humans. Overall, the dogs were shown more than 144 pairs of pictures to select from. The authors observed whether the nine dogs could discriminate any type of dog from other species, and could group all dogs together, whatever their breed, into a single category.
A little bit of history in this post. Did you know that the dog had a key role in the development of blood transfusion technology in humans?
Unfortunately, this is a story of animal experimentation.
In the early 1600s, an English physician named William Harvey explored the circulatory system and declared that ‘blood must continuously circulate.’ For the next 50 years, more work was done to understand the circulatory system. Dogs were unfortunately chosen for animal experimentation and they were injected intravenously with a range of fluids including opium, wine and ale.
In 1665, English physician Richard Lower drained the blood out of a dog almost to the point where it had no blood volume left and was on the verge of death. He then took a larger dog and replaced the blood supply. (Poor dogs)
If you are really interested in the topic of human blood donation, this Science Show video on YouTube explains the whole history of human blood donation…
Professor Michael Day of the School of Veterinary Sciences in Bristol, UK, is the lead author in an article that recommends global monitoring of diseases in dogs and cats. While it is known that many human diseases originate in animals, only diseases in livestock are currently monitored.
Professor Day makes the case that because cats and dogs are integrated into our lives and share our households, the potential for introduction of new zoonotic diseases exists. He says:
‘The number of small companion animals is significant. For example there are an estimated eight to ten million dogs living in up to 31 per cent of UK homes and in the USA, 72 million dogs in 37 per cent of homes.
In developed countries the relationship between man and dogs and cats has deepened, with these animals now closely sharing the human indoor environment. The benefits of pet ownership on human health, well-being and development are unquestionable, but as dogs and cats have moved from the barn, to the house, to the bedroom, the potential for disease spread to humans increases.’
Any new monitoring system will require resources and funding and the political will to see it established. At a time when the global economy is struggling, one can be skeptical about whether there is a chance of seeing this recommendation become a reality.
You can read the article in the Emerging Infections Diseases journal here.
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