Staying with the theme of the relationship with humanity’s oldest friend.
Yesterday, I offered the first of two articles forwarded to me by local friend Jim, a vet, about the domestication of the wolf.
Here is the second.
Study narrows origin of dogs
By Krishna Ramanujan/ January 16th, 2014
Genomic sequencing of genetically divergent dogs, such as this basenji from the Congo, together with wolves and other wild canids, provides rich information about the history of domestic dogs.
Dogs were domesticated between 9,000 and 34,000 years ago, suggesting the earliest dogs most likely arose when humans were still hunting and gathering – before the advent of agriculture around 10,000 years ago, according to an analysis of individual genomes of modern dogs and gray wolves.
An international team of researchers, who published their report in PLoS Genetics Jan. 16, studied genomes of three gray wolves, one each from China, Croatia and Israel – all areas thought to be possible geographic centers of dog domestication. They also studied dog genomes from an African basenji and an Australian dingo; both breeds come from places with no history of wolves, where recent mixing with wolves could not have occurred.
Their findings revealed the three wolves were more closely related to each other than to any of the dogs. Likewise, the two dog genomes and a third boxer genome resembled each other more closely than the wolves. This suggests that modern dogs and gray wolves represent sister branches on an evolutionary tree descending from an older, common ancestor. The results contrast with previous theories that speculated dogs evolved from one of the sampled populations of gray wolves.
“This is an incredibly rich new dataset, and it has allowed us to carry out the most detailed analysis yet of the genetic history of dogs and wolves,” said Adam Siepel, associate professor of biological statistics and computational biology at Cornell and a co-author of the paper. “There are still many open questions, but this study moves the ball forward,” Siepel added.
Computer methods for analyzing complete genome sequences developed by Ilan Gronau, the paper’s second author and a postdoctoral associate in Siepel’s lab, played a key role in the collaboration. Gronau’s computer program, called G-PhoCS (Generalized Phylogenetic Coalescent Sampler), was previously applied with success in a 2011 Nature Genetics study of early human history and demographics.
In this case, G-PhoCS provided a detailed picture of the demographic changes that occurred during the divergence of dogs from wolves. The analysis revealed there was a sizable pruning in population of early dogs and wolves around the time of domestication. Dogs suffered a sixteenfold cut in population size as they diverged from an early wolf ancestor. Gray wolves also experienced sharp drops in population, suggesting that the genetic diversity among both species’ common ancestors was larger than represented by dogs and modern wolves. In addition, there was considerable gene flow between dogs and wolves after domestication. Accounting for gene flow was a major challenge in the analysis, and Gronau’s research on this topic proved valuable in obtaining an accurate model of canid demography.
The picture emerging from this study will allow researchers to better interpret genetic differences observed between dogs and wolves and to identify differences driven by natural selection. “This paper sets the stage for the next step in the study of dog domestication that tries to determine the genetic changes that enabled this amazing transformation,” said Gronau.
The study’s senior authors included geneticists John Novembre at the University of Chicago and Robert Wayne at the University of California, Los Angeles (UCLA). Adam Freeman, a postdoctoral fellow at UCLA, was the paper’s first author. Adam Boyko, a Cornell assistant professor of biomedical sciences, also co-authored the paper.
The study was funded by various sources, including the National Science Foundation, National Institutes of Health and Life Technologies.
Staying with the theme of our early companions, back on the 28th February, 2015 there was an article in the UK’s Guardian newspaper about the way wolves helped early modern man. Now I don’t have permission to republish the full article but here’s a taste:
How hunting with wolves helped humans outsmart the Neanderthals
Forty thousand years ago in Europe our ancestors formed a crucial and lasting alliance that enabled us to finish off our evolutionary cousins, the Neanderthals.
Dogs are humanity’s oldest friends, renowned for their loyalty and abilities to guard, hunt and chase. But modern humans may owe even more to them than we previously realised. We may have to thank them for helping us eradicate our caveman rivals, the Neanderthals.
According to a leading US anthropologist, early dogs, bred from wolves, played a critical role in the modern human’s takeover of Europe 40,000 years ago when we vanquished the Neanderthal locals.
The Guardian article finishes, thus:
Thus we began to change the wolf’s appearance and over the millennia turned them into all the breeds of dog we have today, from corgis to great Danes. Intriguingly, they may have changed our appearances as well, says [Professor Pat] Shipman, whose book, The Invaders: How Humans and Their Dogs Drove Neanderthals to Extinction, will be published this month. Consider the whites of our eyes, she states. The wolf possesses white sclera as does Homo sapiens though, crucially, it is the only primate that has them.
“The main advantage of having white sclera is that it is very easy to work out what another person is gazing at,” added Shipman. “It provides a very useful form of non-verbal communication and would have been of immense help to early hunters. They would been able to communicate silently but very effectively.”
Thus the mutation conferring white sclera could have become increasingly common among modern humans 40,000 years ago and would have conferred an advantage on those who were hunting with dogs.
By contrast, there is no evidence of any kind that Neanderthals had any relationship with dogs and instead they appear to have continued to hunt mammoths and elks on their own, a punishing method for acquiring food. Already stressed by the arrival of modern humans in Europe, our alliance with wolves would have been the final straw for Neanderthals.
Nor does the story stop in Europe, added Shipman. “I would see this as the beginning of the humans’ long invasion of the world. We took dogs with us wherever we went after our alliance formed in the palaeolithic. We took them to America and to the Pacific Islands. They made hunting easy and helped guard our food. It has been a very powerful alliance.”
RISE AND FALL OF NEANDERTHALS
250,000 years ago The first Neanderthals appear in Europe.
200,000 years The first modern humans appear in Africa.
70,000 years The first modern humans leave Africa.
50-60,000 years Modern humans and Neanderthals share territory in Middle East.
45,000 years Modern humans enter Europe.
40,000 years Neanderthals disappear.
I don’t know about you but I find the history of our, as in man’s, relationship with wolves and thence with dogs to be not just romantic but spiritually significant. To know, as I hug one of our many huggable dogs here at home, that I am bonding my mind and emotions with an animal that has been my partner for tens of thousands of years is beautiful beyond words.
(I took a break of a couple of minutes at this point to grab my camera and take a photograph of Hazel sleeping next to my chair, as she so often does when I am writing. Then one of her when she looked up at me. Here they are:)
That second photograph reminds me that somewhere I read that dogs are the only animal that can look to where a human is directing a gaze or pointing a finger.
What an incredible relationship!