Dogs: The blonde coats are from an extinct canine that separated from the gray wolves about two MILLION years ago
The blond coats seen on dogs like golden retrievers come from an extinct canine that separated from gray wolves more than two million years ago, according to a study.
It has long been assumed that thousands of years of selective breeding in our hands were responsible for the diversity of dog coat patterns – but this apparently is not the case.
To color and pattern their coats, dogs and wolves use a combination of two types of pigments: eumelanin, which is black, and pheomelanin, which is yellow.
The production of the latter is controlled by the signaling protein called agouti, or ASIP for short, which is in turn regulated by the gene that makes this protein.
Researchers led by the University of California at Davis have found that variations in two locations of the ASIP gene are responsible for creating five distinct coat patterns.
These are the ‘dominant yellow’, the ‘ombré yellow’, the ‘agouti’ (alternating dark and light bands), the ‘black saddle’ and the ‘black back’.
The blond coats seen on dogs like golden retrievers (pictured) come from an extinct canid that separated from gray wolves more than two million years ago, study finds
THE FIVE REASONS
According to Professor Bannasch and his colleagues, the dogs’ coats come in five distinct patterns.
- Dominant yellow
- Shaded yellow
- Agouti (dark and light bands)
- Black saddle
- Black back
According to the team, the dominant yellow evolved over 2 million years ago, long before dogs were domesticated.
The study was conducted by geneticist Danika Bannasch of the University of California, Davis and her colleagues.
“While we think of all of these coat color variations in dogs, some of them happened long before ‘dogs’ were dogs,” said Professor Bannasch.
“Genetics are proving to be much more interesting because they tell us something about the evolution of canids.”
In their study, Professor Bannasch and his colleagues analyzed the genomes of 77 dogs and wolves with known color patterns.
Their analysis revealed that no genetic mutation could explain the five different coat patterns seen in dogs.
Instead, variations in two different places on the ASIP gene are involved – one related to belly hair and the other to the hair growth cycle.
Additionally, the team found that the genetic combination of the ‘dominant yellow’ motif, which is shared with arctic white wolves, was much older than expected, dating back to a canine that split off from gray wolves. about two million years ago.
For comparison, dogs weren’t domesticated until around 30,000 years ago, the researchers said.
“We were initially surprised to find that white wolves and yellow dogs have an almost identical ASIP DNA configuration,” explained article author Chris Kaelin of the HudsonAlpha Institute for Biotechnology in Huntsville, Alabama. .
“But we were even more surprised when it turned out that a specific DNA pattern was over 2 million years old.”
This, he explained, is “before the emergence of modern wolves as a species.”
Researchers led by the University of California at Davis have found that variations in two locations of the ASIP gene are responsible for creating five distinct coat patterns. These are the ‘dominant yellow’, the ‘shadow yellow’, the ‘agouti’ (that is, with alternating dark and light bands), the ‘black saddle’ and the ‘black back’. In the photo: Examples of different dogs with the five coat patterns
Researchers believe the ancient canid lived in an arctic environment during an ice age 1.5 to 2 million years ago, where lighter coat colors would have been beneficial and naturally chosen.
This, they added, would explain how the coat pattern persisted in the population that ultimately gave birth to modern dogs and wolves.
In contrast, the black back pattern was identified in a 9500 year old sample, showing that the rich variation in coat colors was present in the oldest of our canine companions.
“While we think of all of these coat color variations in dogs, some of them happened long before ‘dogs’ were dogs,” said Professor Bannasch. “Genetics are proving to be much more interesting because they tell us something about the evolution of canids.” Imagine a strand of DNA
While this study is complete, Professor Bannasch is still working with dogs, his current work focusing on identifying the underlying molecular causes of inherited diseases that affect both dogs and horses.
The geneticist is also passionate about breeding and training dogs and her pets include both a “black back” and a Danish-Swedish farm dog with “dominant yellow” patterns.
All she needs now, she joked, are the other three coat designs for a “complete set.”
The full results of the study have been published in the journal Ecology and evolution of nature.
HOW DOGS BECOME DOMESTIC?
New study found dogs and humans have been romantically involved with each other for at least 14,000 years (file photo)
A genetic analysis of the oldest known dog remains in the world revealed that dogs were domesticated 20,000 to 40,000 years ago in a single event by humans living in Eurasia.
Dr Krishna Veeramah, Assistant Professor of Evolution at Stony Brook University, said: “The process of domestication of dogs would have been a very complex process, involving a number of generations where the characteristic traits of the dog gradually evolved.
“The current hypothesis is that the domestication of dogs probably occurred passively, with a wolf population somewhere in the world living on the outskirts of hunter-gatherer camps feeding on human-created waste.
“Those wolves that were more tame and less aggressive would have done better, and although humans initially did not benefit from this process, over time they would have developed a kind of symbiosis. [mutually beneficial] relationship with these animals, eventually evolving into the dogs we see today.