Monday, October 27, 2014

Domestication Syndrome and Neural Crest Cells

How do you take this guy ... and make this guy?

The traits that make them different are their eyes, ear cartilage, fur color, jaw shape and temperament. Scientists have discovered that all five traits are directly controlled by one small cadre of cells (called the neural crest) that tell these parts of the body how to grow.  And because these traits are pre-packaged in one bundle,  if one changes, they all do.   

Mild neural crest cell defincies create weakened ear and tail cartilage,
reduced brain, jaw and muzzle size,  pigment change,
and adrenal changes reducing fearfulness.

An article in the journal Genetics outlines this theory and scientists are confident, that when tested, it will account for the mystery of domestication. 

From Science Daily (July 14, 2014): More than 140 years ago, Charles Darwin noticed something peculiar about domesticated mammals. Compared to their wild ancestors, domestic species are more tame, and they also tend to display a suite of other characteristic features, including floppier ears, patches of white fur, and more juvenile faces with smaller jaws. Since Darwin's observations, the explanation for this pattern has proved elusive, but now, in a Perspectives article published in the journal Genetics, a new hypothesis has been proposed that could explain why breeding for tameness causes changes in such diverse traits.   The underlying link between these features could be the group of embryonic stem cells called the neural crest, suggest the authors. Although this proposal has not yet been tested, it is the first unified hypothesis that connects several components of the "domestication syndrome." It not only applies to mammals like dogs, foxes, pigs, horses, sheep and rabbits, but it may even explain similar changes in domesticated birds and fish."

This would explain the curious outcome of the fox-farm project. Foxes are by nature aggressive and fearful.  Biologists began to breed only the least aggressive and most docile.  In about twenty generations they ended up with foxes that were piebald (spotted), some with floppy ears, curly tails, and shorter legs.
Coat color, ear and tail cartilage, and pigment were affected when biologists
created a population of silver foxes with docile temperaments.

Monday, October 20, 2014

Did ancient indigenous Americans breed their dogs to wolves and coyotes?

The Bureau of American Ethnology was established in 1879 by the U.S. government to preserve Native American culture. The 81 volume collection, published beginning 1879, was digitized in 2009.
Anthropologist and ethnographer 
Frances Densmore recording Mountain Chief
Smithsonian Collection

Since my dissertation was in linguistic anthropology (and my passion is dogs), the first thing I did was look up words for dog.  I figured a comparison might tell if dogs were cross-bred with wolves and/or coyotes.  This is what I found out:

The Yuman people lived in what is now Arizona and California (they still do) and traded with Pima and Seri people. The Yuman word for coyote and wolf is the same, and the word for dog has a similar phonetic sound. Maybe they bred their dogs back to both wolves and coyotes.

Dog                                                                Coyote                                                           Wolf

In the Pima language the words for dog are not similar to words for coyote and wolf.  That suggests their breeds (note list below - they had at least four kinds) were distinctly different than wolves and coyotes. (I circled the word guo because it's like the Chinese word for dog which is gou - makes me wonder if you could use words to track dog migration as people crossed into the Americas from Asia.)
Dog                                                                Coyote                                                      Wolf    

Seri people had similar words for dog and wolf, but the word for coyote is very different. Does this mean they bred dogs back to wolves but not coyotes?  Maybe.

Dog                                                                     Coyote                                                         Wolf 

Looking at reports, depending on what dialect was spoken, the words for dog and wolf are similar.  In rare cases, the words for dog and coyote are similar but the word for wolf is different. This could mean that some tribes bred their dogs back to coyotes, not wolves.  And some first person accounts in diaries from the 1700s indicate that this was the case.
Seri family with napping travois dog, circe 1890
BAE #38
Smithsonian Collection
Not science, but a pretty interesting observation.  As we say when we wear our scholar hats, "More study is needed".

You can find all 81 digitized volumes of the Bureau of American Ethnology at the Smithsonian. If you want to read the print versions, you can find them at Haskell Indian Nations University Library, Lawrence, KS., my home town.

Monday, October 6, 2014

Does the Dog Die in the Movie?

Have you ever seen a movie where totally, out of nowhere, and often for no reason, the dog is killed off?  I'll never be in that situation again - at least not with this website, Does The Dog Die .
" lets viewers learn the fate of a movie pet without spoiling the rest of the film. The icons offer a quick way to find out what happens. You can click on the title of the film. The list offers an explanation which will only contain spoilers relevant to the fate of dogs and other animal characters in the film."  
The icons reveal the fate of the animal.

The site lists 727 movies and you can sort titles alphabetically.