A team of scientists from China have found that the lengthy and intimate association between dogs and humans has resulted in the genomes of both species evolving in parallel over the past 32,000 years.

To study early dog domestication, a team of researchers led by Guo-Dong Wang and Ya-Ping Zhang of the Kunming Institute of Zoology, part of the Chinese Academy of Sciences, sequenced the genomes of four grey wolves from across Eurasia, three indigenous dogs from Southwest China, and three representatives of modern dog breeds. Geneticists believe that indigenous dogs of South China represent the first stage of canine domestication – their genomes may thus hold insights into the transition from wolves to ancestral dogs.

Writing in the journal Nature Communications, the team found that wolves harbored the highest levels of genetic diversity, and modern dog breeds the least, with indigenous Chinese dogs in the middle. The Chinese dogs were also more closely related to wolves than any other native or modern breed surveyed to date, providing evidence for these dogs as the “missing link” in dog domestication.

The researchers put the split between wolves and native Chinese dogs at 32,000 years ago, much earlier than previously thought. The process probably began with wolves scavenging near human populations, a process the researchers call self-domestication.

“The most interesting hypothesis in this research is self-domestication,” says Zhang. “Under this hypothesis, early wolves might have been domesticated as scavengers that were attracted to live and hunt commensally with humans. With successive adaptive changes, these scavengers became progressively more prone to human custody.”

The researchers found that domestication had imposed a strong selective force on genes involved in digestion and metabolism, probably driven by a switch to an omnivorous diet, and on genes governing neurological processes, most likely due to a need for reduced aggression and increased complex interactions with humans.

Intriguingly, the team found that the human counterparts of a number of these genes, particularly those involved in neurological processes, had also experienced strong selection pressure over time, a reflection of the similar environmental factors experienced by humans and dogs over millennia of close association.

Importantly, many of the overlapping genes are associated with similar diseases in man and his best friend. One gene, SLC6A4, encodes a protein that transports the neurotransmitter serotonin.

“Association studies have found that both the receptor and the downstream metabolite of SLC6A4 are correlated with aggressive behavior and obsessive-compulsive disorder not only in humans, but also in dogs,” says Zhang, who adds that studying the genetic basis of diseases in dogs may help us understand similar diseases in humans.

For the researchers, the tale does not end here. To understand domestication in greater detail, the group plans to study gene expression in the canine digestive system and brain, and to expand its research to diverse breeds of dogs from around the world.

An analysis of ancient dog burials finds that the typical prehistoric dog owner ate a lot of seafood, had spiritual beliefs, and wore jewelry that sometimes wound up on the dog.

The study, published in PLoS ONE, is one of the first to directly test if there was a clear relationship between the practice of dog burial and human behaviors. The answer is yes.

“Dog burials appear to be more common in areas where diets were rich in aquatic foods because these same areas also appear to have had the densest human populations and the most cemeteries,” lead author Robert Losey, a University of Alberta anthropologist, told Discovery News.

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The discovery negates speculation that dogs back in the day were just work animals brought along on hunting trips.

“If the practice of burying dogs was solely related to their importance in procuring terrestrial game, we would expect to see them in the Early Holocene (around 9,000 years ago), when human subsistence practices were focused on these animals,” Losey continued. “Further, we would expect to see them in later periods in areas where fish were never really major components of the diet and deer were the primary focus, but they are rare or absent in these regions.”

For the study, Losey and his team researched dog burials worldwide, but focused particularly on ones located in Eastern Siberia. Siberia appears to have been an ancient hotbed of dog lovers, with the earliest known domesticated dog found there and dating to 33,000 years ago. Dog burials in this region, however, span across a more recent 10,000-year period.

The researchers found that most of the dog burials in this area occurred during the Early Neolithic 7,000-8,000 years ago. Dogs were only buried when human hunter-gatherers were also being buried. When pastoralists later came through, they did not bury dogs, although they did sacrifice them from time to time.

“I think the hunter-gatherers here saw some of their dogs as being nearly the same as themselves, even at a spiritual level,” Losey said. “At this time, dogs were the only animals living closely with humans, and they were likely known at an individual level, far more so than any other animal people encountered. People came to know them as unique, special individuals.”

The burials reflect that association. One dog, for example, was laid to rest “much like it is sleeping.” A man was buried with two dogs, one carefully placed to the left of his body, and the other to the right. A dog was buried with a round pebble, possibly a toy or meaningful symbol, placed in its mouth. Still other dogs were buried with ornaments and implements, such as spoons and stone knives.

Two pit bulls believed responsible for injuring three people Friday in Holly Hill were euthanized Monday by the Halifax Humane Society, said Tyler Stover, a spokesman with the shelter.

“The owners had the option to take it to a hearing, but they decided to surrender them,” Stover said.

The same fate may await three of the five pit bulls that were confiscated following a May 5 dog attack in the Daytona North area of western Flagler County. In that case, Flagler County Animal Control officers took possession of five dogs suspected of attacking a mother who was walking along Holly Lane with her 6-year-old daughter.

The girl escaped injury but her mother, Brandi Bookamer, was mauled and hospitalized for bites up and down her arms and legs. Bookamer was released from the hospital but returned for a brief time last week due to complications from her injuries, according to reports. She has turned down numerous requests for an interview.

Diane Voigt, president of the Flagler Humane Society board of directors, said witnesses gave too many conflicting statements to authorities about whether some or all five of the dogs confiscated from 6217 Mahogany Blvd. were involved in that attack.

When people in the neighborhood came to Bookamer’s aid, she was lying in a water-filled ditch and the dogs were still biting her, witnesses said. Eventually, Bookamer positively identified three of the dogs that bit her, said Voigt.

“We took pictures of a bunch of dogs and she (Bookamer) picked out those three,” Voigt said. “She was confident in the ones she picked.”

The board’s decision on whether to euthanize the three dogs could be made Wednesday. The other two will remain at the Flagler Humane Society and may eventually be put up for adoption, given to a pit bull rescue or returned to the owner, Voigt said.

Voigt said 60 percent of the dogs at her shelter are pit bulls or pit bull mixed breeds. That’s common for animal shelters across the Southeast, she said.

The dog attacks in Holly Hill and Daytona North have reignited some debate about whether pit bulls are inherently more dangerous to own than other dogs, but the chance of any sort of ban on the breed is remote. In Florida, a law was passed two decades ago that prohibits counties from enacting ordinances or regulations that focus on or prohibit ownership of specific breeds of dogs. Miami-Dade County passed its own ordinance banning pit bulls years before the state law was signed, so it was granted an exception.

There have been recent efforts to overturn the breed-specific law and officials from some counties — including Broward — have contemplated going before the Florida Legislature to ask for an exemption. But the proposed breed ban in Broward was withdrawn in February following public outcry.

Officials in Flagler and Volusia counties, as well as those from local cities, have not made any moves to ban or restrict pit bulls or other dog breeds but there are attempts to control the numbers. Flagler, on behalf of the Flagler Humane Society, applied for and received a two-year, $83,000 grant from PetSmart Charities to provide free spaying and neutering for pit bulls and pit bull mixed breeds.

The five dogs confiscated from the Mahogany property were spayed, neutered and microchipped at the Flagler Humane Society. The procedures were paid for through the PetSmart grant, according to a shelter official. In general, animal welfare groups, including the American Society for the Prevention of Cruelty to Animals, oppose any laws that target specific dog breeds.

“I don’t think there is any justification to breed-specific legislation,” said Gainesville attorney Marcy LaHart, who handles animal cases across Florida. Her first dangerous dog case was in 2004 in Volusia County. “Unneutered male dogs and female dogs defending a litter will show signs of aggression, but not because they’re pit bulls.”

LaHart said she read news stories about the Daytona North dog mauling and surmised it was another example of someone keeping too many dogs and not supervising them or caring for them appropriately.

“It seems to me this owner had dogs that were breeding indiscriminately,” LaHart said. “If they had been indoor dogs and treated kindly, this accident never would have happened. It seemed this guy’s dogs had been a nuisance for a long time.”

She said pit bulls are “terribly overbred” and those who sell them on Craigslist and other websites and those who buy them put no thought into the quality of the dogs’ lives.

For the seller, it’s an easy way to make money. For the buyer, he or she is buying a guard dog more so than a pet, LaHart said.

As dog attacks continue rising in a growing city, Calgary’s bigger dogs are biting the most.

Reports of dog bites have quadrupled over the past five years.

Last year, more than 70 per cent of reported dog bites came from bigger and medium-sized dog breeds such as bullmastiffs, boxers, German shepherds, Rottweilers and pit bulls, according to new numbers obtained by the Calgary Herald.

Out of 201 reported dog bites last year, 147 were committed by dogs in the working, herding and terrier categories.

And many of the worst offenders are unlicensed, according to Calgary Animal and Bylaw Services.

“Of the trends we’ve seen, 85 per cent of the bites that occur are in the presence of the owner or the person who’s supposed to be in care and control of the dog,� said Andrew Bissett, manager of operations.

“With trends, it goes right back to understanding the behaviours of their dog. You need to know your animal.�

Forest Lawn had the most dog bites in the city, with 11 attacks reported in 2012, according to documents obtained by the Herald.

Bowness followed with eight incidents, Falconridge with seven, Marlborough with six, and Ogden with five.

City officials say the increase in dog bite reports stems from improved reporting by citizens as a result of public education efforts. There were 58 dog attacks in 2009, 102 in 2010, 127 in 2011 and 201 last year.

The city introduced its responsible pet ownership bylaw in 2006, placing the onus of animal behaviour on pet owners. Calgary’s bylaw department emphasizes responsible pet ownership through intensive licensing, hefty fines and owner education.

High-profile dog attacks have routinely sparked calls for breed-specific legislation that bans or restricts certain types of dogs considered dangerous. Pet advocates say there’s no such thing as bad dog breeds, only bad owners.

An online poll last month done by Leger Marketing for Postmedia News showed 48 per cent were against breed bans, 40 per cent backed them and the rest were undecided.

Winnipeg enacted the country’s first major ban on pit bull-type dogs in 1990. Ontario followed suit in 2005, and other municipalities in the United States have put restrictions in place.

Calgary has no plans to introduce a breed ban.

The Calgary Humane Society says owners of big dogs have an extra responsibility to train them. “All dogs have the ability to bite, but it’s the strength of the bite from the bigger ones that’s so worrisome,� said society spokeswoman Christy Thompson.

“Bigger dogs are stronger and bites are more likely to be reported,� she said. “We’re really pushing education around socializing for all dogs so they’re not surprised. People really need to understand that.�

Dog bite reports have been increasing steadily in the past four years.

In April, Calgary police officers, including a sergeant who suffered a bite to the leg, were forced to use Tasers to capture two female Tibetan mastiffs running loose near a Martindale elementary school.

For two to three blocks, the officers followed the large dogs along the tracks until one officer deployed a Taser to capture one of the animals.