According to a team of genetic scientists from the Ilia State University’s Institute of Ecology in Tbilisi, Georgia, hybridization of wolves (Canis lupus) with shepherd dogs (Canis lupus familiaris) in the Caucasus Mountains might be more recent than previously thought.
Livestock guarding dog, upper, livestock guarding dog with the inferred wolf ancestry – first-generation hybrid, middle, and a wolf; all from Kazbegi, Georgia. Credit: Natia Kopaliani et al.
The scientists used a range of genetic techniques to extract and examine DNA taken from wolf and dog fur samples as well as wolf scat and blood samples. They found recent hybrid ancestry in about ten percent of the dogs and wolves sampled.
About 2-3 percent of the sampled wolves and dogs were identified as first-generation hybrids. This included hybridization between wolves and the shepherd dogs used to guard sheep from wolf attacks.
“Since the 2000s, the frequency of wolf depredation on cattle has increased in Georgia, and there were several reports of attacks on humans. Wolves were sighted even in densely populated areas,” said Dr Natia Kopaliani, the lead author of the paper published in the Journal of Heredity.
“Reports suggested that, unlike wild wolves, wolf-dog hybrids might lack fear of humans, so we wanted to examine the ancestry of wolves near human settlements to determine if they could be of hybrid origin with free-ranging dogs such as shepherds.”
Dr Kopaliani and her colleagues examined mitochondrial DNA and microsatellite markers to study hybridization rates. Microsatellite markers mutate easily, as they do not have any discernible purpose in the genome, and are highly variable even within a single population. For these reasons, they are often used to study hybridization.
“We expected to identify some individuals with hybrid ancestry, but it was quite surprising that recent hybrid ancestry was found in every tenth wolf and every tenth shepherd dog,” said co-author Dr David Tarkhnishvili.
“Two dogs out of the 60 or so we studied were inferred to be first generation hybrids.”
The researchers also found that about a third of the dogs sampled shared relatively recent maternal ancestry with local wolves, not with wolves domesticated in the Far East, where most experts believe dogs were first domesticated.
They used several alternate methods to confirm their results, and came to the same conclusions with each approach.
The shepherd dogs studied are a local breed used to guard livestock.
“Ironically, their sole function is to protect sheep from wolves or thieves. The shepherd dogs are free-ranging, largely outside the tight control of their human masters. They guard the herds from wolves, which are common in the areas where they are used, but it appears that they are also consorting with the enemy,” Dr Kopaliani said.
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Natia Kopaliani et al. 2014. Gene Flow between Wolf and Shepherd Dog Populations in Georgia (Caucasus). Journal of Heredity 105 (3): 345-353; doi: 10.1093/jhered/esu014
