Cooked or Raw? Reference (1) listed below in the bibliography is a study published in the Journal of Archaeological Science and it covers information concerning the 'dog as ancestor of wolf' debate. It is established in their study that dogs were domesticated long ago (at least 31,000 years or more), and differentiated from wolves quickly (bone structure, larger brain casing, teeth placement, etc).

As you can see from the time line listed below, dogs have evolved over the course of many thousands of years to digest a diet very different from the wild wolf.
 

• 31,700 years ago (The Aurignacian period) – Dogs are living with humans and assisting with the hunt during parts of the year, being fed portions of horse, musk ox and reindeer during periods of the year when humans hunted and fending for themselves during the seasons when humans subsisted on fish. (1)(2)

• 20,000 - 9,500 BC (The Mesolithic era, Denmark and Yorkshire, England) – Dogs, along with humans, migrate repeatedly between the inland and the coast and eat fish and other “marine food.” (3)(4)(5)
   
• 9,000 years ago – Humans migrate across the Bering land bridge from Asia, most likely bringing dogs or semi-tame wolves with them. (6)
   
• 7,000 – 8,000 years ago (The Neolithic era) – As humans begin to abandon the hunter-gatherer lifestyle for farming, dogs are used to guard flocks of livestock. There are also semi-feral dogs that live by scavenging food on the edges of human settlements. (6)(7)
   
• ~300 BC (Roman Empire) – In addition to the above roles, dogs are kept as status symbols by the nobility. Molossian hounds, which originated in Greece, are fed “freshly killed oxen” when kept as guard dogs. When used for sheep herding, they are fed “rich fresh whey” to prevent them acquiring a taste for flesh. (6)(8)
   
• 250 – 700 AD (Mayan civilization, Belize) – Dogs, along with humans, are fed large amounts of maize (corn). (9)
   
• Before 1200 AD – Small hairless dogs kept by the Toltec receive “lavish meals of freshly baked, sweetened corn cakes or potato and Guinea pig stew.” (6)
   
• 1300s AD (Medieval Europe) – Dogs kept by the nobility are treated with great affection and fed “slabs of venison or grain-fattened beef.” Stocky dogs employed for guard duty are sometimes fed “dried meat or loaves of bread.” (6)
   
• 1500s – 1800s (North American Arctic) – “Early European explorers often remarked on the…insatiable appetites of Indian dogs, particularly those kept by the Inuit tribes of the far north…These dogs were forced to think creatively when it came to procuring food. If hunting was bountiful they were likely to receive extra portions of fish or seal meat, expressly smoked or frozen for that purpose. More often, though, they subsisted on virtually inedible leavings, including bones, scraps of hide, and even human feces.” Elisha Kane recounts an instance where one dog consumed two birds’ nests, “feathers, filth, pebbles and moss.” (6)
   
• ~1300s – mid 1800s – Hunting dogs belonging to peasants generally live on a meatless diet consisting of potatoes, bread and boiled cabbage – similar to the diet of their masters. “Trencher feeding” is common: people eat meals off of large crusts of bread, which were then “tossed to the dogs.” (6)(10)
   
• 1500s – late 1800s (Europe) – Turnspit Dogs, or Turnspetes, are employed to run on a large wooden wheel (similar in form to those that now meet the exercise needs of pet rodents) for long periods, often with little food or hydration – they “were lucky to get anything beyond a crust of bread or a greasy knuckle of bone” - in order to rotate meat or poultry on a spit for even cooking. (6)
   
• 1700 AD (England) – Ivory carving depicts an overweight dog owned by a noble. (6)
   
• 1700s (France) – Dogs belonging to French royals are often fed “succulent bits of roast duck, consommé, cakes, and candied nuts or fruit.” (6)
   
• Mid 1800s – Horsemeat becomes a big part of the diets of dogs and cats in urban working-class households due to low cost and high availability. Leftovers of “people food” also grow more varied. (6)
   
• Late 1800s – Humans become somewhat obsessed with their digestive systems and project this concern onto their dogs. Some believe that to tame their 'primal passions', dogs should not be fed too much meat, particularly raw meat. Some veterinarians and other experts cautiously argue otherwise. “American veterinarian A.C. Daniels prescribes a recipe for homemade ‘canine cakes’ of boiled, minced beef or mutton, mixed with rice and vegetables, then baked…” (6)
   
• Kennel masters for the wealthy, on the other hand, develop their own recipes, which might consist of vegetables, slaughterhouse leftovers and “a few ‘secret ingredients’ that might be anything from a splash of sherry to a pinch of gunpowder.” (6)
   
• 1850s – 1860s – James Spratt, an electrician from Cincinnati (USA), travels to London (UK) to sell lightning rods. At some point he observes stray dogs being thrown “moldy hardtack biscuits and scraps of rotten food.” He is inspired to develop a biscuit specifically formulated for dogs. Spratt’s Patent Meat Fibrine Dog Cakes, made up of wheat, beetroot, vegetables, and beef blood, begin to be marketed in England in 1860. Other commercial dog foods soon follow, most of them referred to as “breads, cakes or biscuits”. (6)(10)
   
• 1880s – 1945 – Spratt’s begins selling in the U.S. in 1881. Commercial pet foods increase in popularity as people begin to value their leisure time more. A large number of new brands arise, some coming from companies looking for a way to use up waste from granaries and slaughterhouses. Many people continue to feed their dogs table scraps. Sometime in the period between 1926 and 1950 (11), Veterinarian Raymond J. Garbutt observes an increased incidence of hemorrhoids in dogs, in part (he believed) due to the feeding of dry kibble. (6)(12)
   
• 1907 – Milkbone dog biscuits come to the market, billed as a complete dog food. Milkbone and Spratt dominate the dog food market until the 1920s. (10)
   
• 1929 – Ken-L-Ration canned dog food ads appear in Ladies’ Home Journal. (12)
   
• 1935 – 200 companies manufacture dog food in the U.S. (6)
   
• 1930s – Canned dog food, which had become popular after World War I due to the availability of cheap horsemeat, increases in popularity, becoming 91% of the U.S. dog food market by 1941. However, it falls out of favor during World War II, when tin cans are in short supply. By 1946, dry dog food again heads the market. (10)
   
• 1975 – 1,500 dog food manufacturers are in business in the U.S. (10)
   
• 1980s – People become concerned about food additives for themselves and their pets. Pet food companies begin giving themselves a more scientific image, emphasizing their research and attempting to add credibility to their nutritional claims. Industry-sponsored research is claimed to show that dogs are omnivores and require whole grains and vegetables in addition to meat. (6)

1. Germonpré M, Sablin MV, Stevens RE, Hedges RE, Hofreiter M, Stiller M, Després VR. Fossil dogs and wolves from Palaeolithic sites in Belgium, the Ukraine and Russia: osteometry, ancient DNA and stable isotopes. Journal of Archaeological Science. 2009 ;36(2):473–490.
2. Viegas J. World's first dog lived 31,700 years ago, ate big [Internet]. Discovery.com- msnbc.com. 2008 Oct 17;[cited 2009 Nov 18 ] Available from: http://www.msnbc.msn.com/id/27240370/)
3. Fischer A, Olsen J, Richards M, Heinemeier J, Sveinbj\örnsdóttir ÁE, Bennike P. Coast–inland mobility and diet in the Danish Mesolithic and Neolithic: evidence from stable isotope values of humans and dogs. Journal of Archaeological Science. 2007 ;34(12):2125–2150.
4. Clutton-Brock J, Noe-Nygaard N. New osteological and C-isotope evidence on Mesolithic dogs: companions to hunters and fishers at Star Carr, Seamer Carr and Kongemose [from abstract]. Journal of Archaeological Science. 1990 ;17643–653.
5. Schulting RJ, Richards MP. Dogs, Ducks, Deer and Diet: New Stable Isotope Evidence on Early Mesolithic Dogs from the Vale of Pickering, North-east England [from abstract] [Internet]. Journal of Archaeological Science. 2002 Apr ;29(4):327-333.[cited 2009 Nov 19 ] Available from: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WH8-45WGH5X-9&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1101363515&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=6c2ff72159085526d2a6c9b9b34b13c8
6. Thurston M. The lost history of the canine race : our 15,000-year love affair with dogs. Kansas City Mo.: Andrews and McMeel; 1996.
7. Bartosiewicz L. Dogs from the Ig pile dwellings in the National Museum of Slovenia. Arheoloski vestnik. 2002.
8. Green S. Immortalised in stone, dogs held a vital place in ancient Rome. The Guardian. 2001 Nov 17.
9. White CD, Healy PF, Schwarcz HP. Intensive Agriculture, Social Status, and Maya Diet at Pacbitun, Belize [Internet]. Journal of Anthropological Research. 1993 Winter ;49(4):347-375.[cited 2009 Nov 19 ] Available from: http://www.jstor.org/stable/3630154
10. Burns P. A Brief History of Dog Food [Internet]. Terrierman's Daily Dose. 2008 Aug 9;[cited 2009 Nov 7 ] Available from: http://terriermandotcom.blogspot.com/2004/09/history-of-dog-food.html
11. Guide to the Raymond J. Garbutt papers, 1926-1950 [Internet]. [cited 2009 Dec 2 ] Available from: http://rmc.library.cornell.edu/ead/htmldocs/RMM06608.html
12. Grier KC. Pets in America: A history. The University of North Carolina Press; 2006.