May 30, 2017 | David F. Coppedge

Dog Breeding: Exploring the Limits of Change

by David F. Coppedge

People have loved (or hated) dogs for thousands of years. Dogs were frowned upon as dirty scavengers in Biblical times, but for many centuries more recently, they have been man’s best friend. Because of their usefulness for hunting and herding, people groups around the world have bred individuals to accentuate traits they desired. A new survey of 160 dog breeds, described in Nature, shows that genetics is now allowing scientists to untangle the complicated lineages of different types.

In a study published on 25 April in Cell Reports, scientists examined the genomes of 1,346 dogs to create one of the most diverse maps produced so far tracing the relationship between breeds. The map shows the types of dog that people crossed to create modern breeds and reveals that canines bred to perform similar functions, such as working and herding dogs, don’t necessarily share the same origins. The analysis even hints at an ancient type of dog that could have come over to the Americas with people thousands of years before Christopher Columbus arrived in the New World.

The results were surprising to those who expected breeds with similar traits to be related. That wasn’t necessarily the case. If different tribes on different continents bred their dogs for similar functions, the genetic lineages would differ, even if the resulting dogs had similar abilities.

“You would never be able to find something like this with cows or cats,” says Wayne, “We haven’t done this kind of intense deliberate breeding with anything but dogs.”

“I think our view of the formation of modern dog breeds has historically been one-dimensional,” says Bob Wayne, an evolutionary biologist at the University of California, Los Angeles. “We didn’t consider that the process has a deep historical legacy.

That extends to what was probably the first period of domestication for canines in hunter-gatherer times. Ostrander and Parker think that dog breeds underwent two major periods of diversification. Thousands of years ago, dogs were selected for their skills, whereas a few hundred years ago, the animals were bred for physical traits.

“You would never be able to find something like this with cows or cats,” says Wayne, “We haven’t done this kind of intense deliberate breeding with anything but dogs.

Only in recent centuries have people bred dogs for their looks instead of their abilities (think highly-groomed pink poodles at dog shows). The BBC News adds more details about the study:

They identified 23 clusters (clades) of dog breeds that are all similar to each other.

You can now tell where different dog breeds came from – and the diseases they are prone to, they say.

For example, gun dogs all seem to have developed in one place and time – Victorian England.

“All of the spaniels, the pointers, the setters and the retrievers are actually pretty closely-related and they group into one over-arching clade [cluster] of sporting breeds,” said Dr Parker.

However, other dogs that appear to be similar – such as herding dogs – are actually quite diverse, suggesting they were bred to fill certain roles many times in history in different places over the course of thousands of years.

The diversity between today’s dog breeds surely must strike one as remarkable: the St. Bernard vs the chihuahua, the dachschund vs the greyhound. Yet all of them share many traits of dogness in common: turning around before lying down, panting, barking. Although it might be difficult to demonstrate, they are all interfertile, too, indicating they are one species. Enough cross-breeding would probably make them revert to wild type, like the wolf from which all are thought to be descended. The mark of artificial selection – a form of intelligent design – is found throughout all dog breeds.

Humans Smell Good, Too

our sense of smell is similar to that of other mammals

We often think of dogs as experts in olfaction (sense of smell). That’s demonstrably true; it’s why police use bloodhounds to find their man. But the notion that human olfaction is inferior to that of dogs and other mammals is a myth, reports John P. McGann in Science Magazine. The introduction explains:

In comparison to that of other animals, the human sense of smell is widely considered to be weak and underdeveloped. This is, however, an unproven hypothesis. In a Review, McGann traces the origins of this false belief back to comparative 19th-century neuroanatomical studies by Broca. A modern look at the human olfactory bulb shows that it is rather large compared with those of rats and mice, which are presumed to possess a superior sense of smell. In fact, the number of olfactory bulb neurons across 24 mammalian species is comparatively similar, with humans in the middle of the pack, and our sense of smell is similar to that of other mammals.

S. Craig Roberts shares the same story in The Conversation: “It’s a myth that humans’ sense of smell is inferior to that of other animals – here’s why.” Then Live Science uses pun fun for its headline: “People Smell Great! Human Sniffers Sensitive as Dogs’.” There’s a topic for water-cooler conversation, and perhaps a fun science project for Junior to undertake with the family dog.

Charles Darwin made a big deal out of artificial selection as an analogue to natural selection, but that’s a false comparison. The former is intelligent design, for one thing; it’s like comparing a sand castle to ripples on a beach. Both are made of sand, but you will never get a sand castle by unguided natural processes. A second problem is that the breeds are still the same animal. Pigeons are pigeons. Dogs are dogs. Cattle are cattle. As we saw, all bears are probably genetically related (4/24/17). These cases of ‘micro-evolution’ have never been demonstrated to cross the genetic barriers into a new higher-level taxon, like an order or family, let alone a new genus or species.

Creationists often use dog breeds as an example of variation within a created kind. Nothing in these news articles changes their assertion that God put a lot of inherent variability into the groupings that reproduce ‘after their kind’, as Genesis repeats ten times for emphasis. Environments (such as temperature or elevation) will accentuate certain traits at the expense of others. Human breeders can accentuate them to extremes. But a dog will never become a cat, and a wolf will never become a whale, because those kinds of animals have different genomes. Nevertheless, a significant amount of variation within created kinds undoubtedly occurred between creation and the Flood, and after the genetic bottleneck of the Flood. We might barely recognize the animals that came off the ark. That’s not evolution as Darwin envisaged it; it’s the sorting out of genetic information within groups that reproduce ‘after their kind.’

For more on creation answers to variability, search for articles on baraminology, the creation science of genetic processes and taxonomical principles that affect created kinds. Baramin is taken from the Genesis word for ‘kind.’ That’s not any more contrived than ‘species’, a word that also originally reflected the word kind. So be kind with humankind. Don’t make an issue of the terminology when there is none.

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