<p>From pups that fit in purses to those that seem fit for a stable, <a href="http://www.livescience.com/6023-genes-dogs-breeds-discovered.html">dog breeds</a> run the gamut of size, shape, temperament and overall look. But they have one thing in common: All dog breeds can trace their heritage back to the gray wolf, though scientists are less sure where today's Fidos originated. Gradually<a href="http://www.livescience.com/8043-breeding-dogs-heads-incredibly-diverse.html"> humans selected for traits</a> they found useful, or just downright cute, in their dogs — herding ability, particular temperament, fishing acumen — the <a href="http://www.livescience.com/animals/dog-dna-100301.html">canines diversified</a>.</p><p> Every year, the American Kennel Club (AKC) announces their list of the most popular breeds. Here are the 10 dogs that are relative mainstays on the Top 10 most popular dog breeds' list.</p>
<p>Affectionately called "Labs," these athletic dogs are originally from Newfoundland where they worked alongside fishermen to help pull nets and catch fish that escaped from fishing lines, according to the AKC. The breed didn't get its superb retriever skills until it was crossed with setters, spaniels and other retrievers. Since then Labrador retrievers, which come in yellow, black and chocolate coat colors, have been bred as skilled retrievers of game; they're also widely praised for their stable temperament.</p><p> Even so, the breed is vulnerable to exercise-induced collapse (EIC), which occurs after intense hunting or retrieving, when affected Labradors lose control of their hind limbs. A study published in 2008 in the journal Nature Genetics revealed the wobbly legs are linked to the so-called dynamin 1 gene. The study researchers found some 30 percent of Labrador retrievers carry the mutant gene though they may not show symptoms since they don't carry two copies of the dynamin 1 variant. The scientists developed a genetic test to determine whether a dog is carrying a copy of the mutant gene to help breeders avoid pairing up two carriers.</p>
<p>This dog may be the closest to having a 9-to-5 gig, as the <a href="http://www.livescience.com/14897-dogs-identical-twins.html">German shepherd</a> is the gold standard when it comes to police, guard and military dogs. The breed was derived from a mix of herding and farm dogs and originated in 1899 in Karlsruhe, Germany, according to the AKC. Its debut in America occurred in 1907. The German shepherd is a mainstay on the top of the Club's annual most popular list.</p>
<p>Yorkies, as they are affectionately called, are part of the toy group (a category that also includes the Chihuahua), and weigh between 4 and 7 pounds (1.8 and 3.2 kg). Named for the city in England where they originated, Yorkshire terriers were used to catch rats in clothing mills in the 19th century. Though this <a href="http://www.livescience.com/10646-origin-small-dogs-pinned.html">portable pooch</a> is now an accessory of the rich and famous, the breed once belonged to the working class, particularly weavers, according to the AKC.</p>
<p>This intelligent dog was bred into existence by Lord Tweedmouth, who wanted a skilled retriever that was suited to the Scottish climate, terrain and available game, according to the AKC. So he crossed his "Yellow retriever" with the now extinct Tweed Water Spaniel. Later crosses of Irish setter, bloodhound and other Tweed Water spaniels produced the golden retriever of today. The dog's hard-working mindset not only makes the breed a superb hunter but also ideal guide, search and rescue and assistance dogs.</p>
<p>Perhaps the best-known individual of this breed, Snoopy may not give a true picture of beagles. While they aren't human-like (and don't confuse themselves with humans), the breed's hunting acumen and cheery temperament have made the beagle one of the most popular breeds in the United States, according to the AKC. In the 1500s, English gentlemen with packs of hounds were a common sight. The larger hounds tracked deer while the smaller ones sniffed out rabbits. In fact, the name "beagle" may have come from the French term "be'geule," referring to the baying voice of the hounds when going after game, or due to the hound's diminutive size, according to the AKC.
<p>Known for standing up on its hind legs to duke it out with an opponent, this dog breed can appear to box with its front paws. In fact, when developed in Germany in the 19th century, boxers were used for dog fighting as well as to restrain large game like wild boar until a hunter arrived, according to the AKC. They first arrived in America after World War I, growing in popularity in the late 1930s. And though used for dog fighting, the boxer is most notable for its love of human affection, particularly from children.
<p>This dog owes its popularity to its lovable nature and adorable appearance – who can resist the squashed, wrinkly face? Their flattened noses, however, make them susceptible to overheating in warm weather, since rather than sweating dogs cool off by panting or breathing in and out. With a shorter snout there's less surface area over which heat exchange can take place.</p>
Though extremely affectionate now, the bulldog gets its name due to its connection with bull baiting in the British Isles. As a result of occupational hazards, the first bulldogs had to be ferocious and nearly insensitive to pain, according to the AKC. Once bull baiting became illegal in England in 1835, dog fanciers decided to get rid of the bulldog's "bite." Within just a few generations, the bulldog became the epitome of sweetness.</p><p>
While the bulldog snagged spot 7 and spot 6 in 2009 and 2010, respectively, in the American Kennel Club's most popular dog breeds, the cute pup didn't make the Top 10 list in 2000 or 2005. </p>
<p>... or "hotdogs" were bred with the goal of a fearless, lengthy canine that could dig into badger burrows and "fight to the death" with the vicious badgers, according to AKC. Though first bred in Germany in the early 1600s, they didn't become popular in the United States until the early 1900s. During World War I the badger dog's popularity waned, not getting much notice again until after the war ended. Two sizes of dachshunds exist today: standard (weighing 16 to 32 pounds, or about 7 to 14.5 kg) and miniature (11 pounds and under, or 5 kg).</p>
<p>Though its airy curls may have you believe differently, the poodle is not a fluffy toy and rather the dog breed sports major smarts and excels in obedience training.</p><p>
First bred in Germany as a water retriever, the poodle got its hairstyle was actually from hunters who wanted to help the dogs move more efficiently through the water without so much drag. The remaining patches of hair protect vital organs and joints vulnerable to the cold. Three size variations exist: The standard variety, the oldest of the three, is the only one to have its genome sequenced, a feat reported in 2003; the miniature may have been used to sniff out truffles – an edible fungus considered a delicacy; and the toy poodle was often used in performances and kept as a pampered pet. For instance, during the reign of Louis XVI in France, toy poodles were all the rage.</p>
Poodles come in a variety of coat colors, including white, black, apricot and gray. But research published in 2007 in the journal Science reveals all poodle coats and those of nine other breeds arise from a gene called beta-defensin that encodes black and yellow coat color. And all colors in between are just modifications of yellow and black, the researchers said.
<p>This <a href="http://www.livescience.com/7268-study-reveals-dogs-small.html">toy dog</a> has a "distinctively arrogant carriage with his head well up and tail curved over the back," according to the AKC. So it only makes sense shih tzu's were cherished by Chinese royals as prized house pets for over a thousand years. Research by the AKC suggests the breed descended from crossing the Lhasa Apso or Tibetan mountain dog and Pekingese. The shih tzu was the house pet for most of the Ming Dynasty, from 1368 – 1644, and was discovered by soldiers in England during World War II. [<a href="http://www.livescience.com/13305-facts-dog-breeds-genetics-pets.html">10 Fun Facts About Dogs</a>]</p>