{"id":3844,"date":"2022-03-10T10:00:00","date_gmt":"2022-03-10T10:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=3844"},"modified":"2022-02-23T10:34:21","modified_gmt":"2022-02-23T10:34:21","slug":"these-toy-dog-genes-can-be-traced-back-to-54000-year-old-wolves","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/these-toy-dog-genes-can-be-traced-back-to-54000-year-old-wolves\/","title":{"rendered":"These \u201cToy\u201d Dog Genes Can Be Traced Back to 54,000-Year-Old Wolves"},"content":{"rendered":"\n

Your nearest Chihuahua may appear so distant in appearance to its wolf-like ancestors that they might as well be entirely different animals, but their cute veneer hides select genes that brought about their \u201ctoy-like\u201d appearance\u2014and if recent studies are anything to go by, they might actually be a link to their distant wolven past<\/a>.<\/p>\n\n\n\n

The study in question, which was published in the journal Current Biology<\/em><\/a>, gathered their necessary data from the National Institutes of Health<\/a> (NIH) through the institution\u2019s National Human Genome Research Institute<\/a> (NHGRI) Dog Genome Project<\/a> (DGP), a citizen science project which focuses on the health and body structure in the domestic dog (Canis lupus familiaris<\/em>) across all its breeds by having owners collect DNA samples of their pet dogs.<\/p>\n\n\n\n

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Pomeranians may look small, but they\u2019re roughly just as closely related to more wolven ancestors as the rest of the dog breeds. (Pickering, 2021)<\/figcaption><\/figure><\/div>\n\n\n\n

From there, the team of scientists responsible for the study located the genetic mutation responsible for small dog breeds like Chihuahuas and Pomeranians, and found them within the insulin-like growth factor 1<\/em> (IGF1) gene. Thing is, after cooperation with other researchers from England and Germany, the scientists there also found IGF1, but this time in 54,000-year-old DNA sourced from Siberian wolves (Canis lupus campestris<\/em>). Additionally, the mutation can also be found in other living canids, like golden jackals (Canis aureus<\/em>) and coyotes (Canis latrans<\/em>).<\/p>\n\n\n\n

“It’s as though nature had kept it tucked in her back pocket for tens of thousands of years until it was needed,” said senior author and NIH geneticist Elaine Ostrander, who specializes in dogs, in an official statement<\/a>.<\/p>\n\n\n\n

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Coyotes (Canis latrans<\/em>) are a species of canine native to North America. (Ferreira, 2019)<\/figcaption><\/figure><\/div>\n\n\n\n

To be specific, the mutation lies near the IGF1 gene section of canine DNA, which when expressed can influence the body size of the dog as it grows up. Alleles<\/em>, or variants of the gene, from dog parents can include either an extra cytosine<\/em> (C) or thymine<\/em> (T) base, which express a small or large body size respectively. Once a dog inherits two alleles of the gene from both its parents, it may then end up with different combinations of alleles: CC, CT, or TT.<\/p>\n\n\n\n

The research team found a major correlation between these allele combinations and dog sizes: \u201cCC\u201d yielded small dogs like the aforementioned \u201ctoy\u201d breeds; \u201cCT\u201d led to medium-sized dogs; and \u201cTT\u201d was strongly correlated with larger dogs.<\/p>\n\n\n\n

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Different combinations of alleles were found to be strongly correlated to canine sizes, including those of our loyal Pomeranian and Chihuahua companions. (Plassais et al, 2022)<\/figcaption><\/figure><\/div>\n\n\n\n

“We were surprised to find the mutation and delighted to find that both variants [C and T] were present over 54,000 years ago,” Ostrander told LiveScience<\/a>, noting how the same IGF1 mutation was found in both ancient Siberian wolf DNA and in the DNA of modern-day jackals and coyotes, which all possessed the CC allele combination (two copies of the C allele).<\/p>\n\n\n\n

Ostrander and the team also noted that the petite nature of dog breeds around today would never have been achieved naturally, and was thus partially due to human domestication and breeding. Ostrander added to this by saying “[the] small allele was maintained at a low level for tens of thousands of years until it was selected on during or around the time of domestication.\u201d<\/p>\n\n\n\n

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The genes that express how big or small dogs end up being apparently stretch further back into their family tree than scientists once thought. (Doctorow, 2007)<\/figcaption><\/figure><\/div>\n\n\n\n

It must be noted, however, that the IGF1 gene is not solely responsible for dog body sizes; the gene joins a 20-strong list of genes that are known to express body size in canines, much like how hundreds of genes do a similar function in humans.<\/p>\n\n\n\n

The team notes that future studies on the topic will include an analysis of the proteins produced by these special dog size genes to determine how they work together to create \u201cbig dogs, little dogs, and everything in between,\u201d according to Ostrander.<\/p>\n\n\n\n

(For more dog news, read about how their cute head tilts may be a sign of concentration and brain activity<\/a>.)<\/p>\n\n\n\n

References<\/h2>\n\n\n\n