According to a recent study, evolution shaped the genes in humans and dogs that relate to diet, behavior, and disease.
The bond betweendogs and humans is ancient and enduring. Dogs cuddle up to us at night, play fetch with us on daily walks, and fall adorably to the ground when we collapse on our couches. However, recent findings indicate that the connection is stronger than previously believed. It is embedded in our genes.
Numerous groups of genes, such as those involved in diet and digestion, neurological functions, and disease, have been evolving in parallel in humans and dogs for thousands of years, according to research from the University of Chicago and several other international institutions.
According to a study that was published on May 14 in the journal Nature Communications, the shared environments of humans and dogs were probably what drove this parallel evolution.
The authors speculate that because domestication is frequently linked to sharp increases in population density and cramped living conditions, these unfavorable environments may have served as the selective pressure that caused the rewiring of both species.
Dogs may have been domesticated 32,000 years ago, according to the study’s authors, which is much earlier than the current estimate of 15,000–16,000 years. (Related:”Ancient Dog Skull Shows Early Pet Domestication. “).
Bob Wayne, an evolutionary biologist at the University of California, Los Angeles, said, “Thirty-two thousand is a little bit old.” Despite the fact that he acknowledges that the age of the split between wolves and dogs has varied greatly—from 6,000 to 120,000 years ago
The authors of the study also suggested that dog domestication began in Southeast Asia rather than the Middle East, contrary to what other theories have claimed.
Four gray wolves from China and Russia, three Chinese street dogs, and three domestic breeds—a German shepherd, a Belgian Malinois, and a Tibetan mastiff—had their genomes sequenced by the researchers for the study.
Then, they were able to determine which genes were linked to domestication and when that change may have taken place. The team also examined the domestication-related dog genes and compared them to human genes.
Weiwei Zhai, co-author of the study and a genetics researcher at the Chinese Academy of Sciences in Beijing, stated in an email that “the history of dog domestication is frequently depicted as a two-stage process.” “The first stage is from wolves to dogs. The second stage is from dogs to breeds. (From National Geographic magazine’s article titled “How to Build a Dog”) ).
Due to their higher genetic diversity compared to other street dogs from around the world, Southeastern Asia street dogs, including the Chinese street dogs in the study, may be an evolutionary bridge between wolves and purebred dogs, according to Zhai. As a result, the Chinese street dogs would serve as a kind of “missing link” for canines.
Zhai and colleagues found that sequences for things like the transport of neurotransmitters like serotonin, cholesterol processing, and cancer have been selected for in both humans and dogs when they compared their canine sequences with the human genome.
Although convergent evolution, or selection in the same gene in two different species, is uncommon in nature, said Zhai, their findings weren’t particularly surprising. After all, dogs and people have lived together in harmony for a long time.
Ya-ping Zhang, a professor at the Chinese Academy of Sciences in Kunming (map), wrote in an email that humans and dogs share diseases like obesity, obsessive-compulsive disorder, epilepsy, and some cancers like breast cancer in addition to genes that affect diet and behavior.
According to Zhai, this may be because genes frequently have multiple effects. “While some effects will be positive, others may be negative.” The gene can still be chosen [for] when the selective benefit outweighs the detrimental cost. “.
According to Zhai, these kinds of processes may have led to the co-evolution of the cancer-related genes that the research team discovered in both dogs and humans.
According to UCLA’s Wayne, who provided reference data the study authors compared with their genetic sequences, “This is nice that [their study is] based on complete genome data.” Other studies have used only snippets, such as mitochondrial DNA.
He added that, in addition to China and Russia, the analysis of canine sequences from other locations would have helped in the dating of domestication and in determining its location. However, he cautioned that comparing human and canine genomes can be challenging.
Wayne added that it is also difficult to determine whether the parallel evolution in the genomes of humans and dogs is a unique phenomenon without further comparisons between humans and other domestic animals like goats or horses.
Nevertheless, he continued, the study adds a new chapter to the domestication of dogs—a story that is far from over.
How Do We Know What Percentage of DNA Two Species Share?
Comparing two species’ entire DNA sequences (or genomes) to one another is the most precise way to calculate the precise percentage of DNA that each species shares. However, it is a challenging task that requires a lot of time and effort to determine an animal’s entire DNA sequence. To do this, a lot of tools, materials, and money are needed.
The authors of the new study warn that there are additional factors at work even though it provides some insights into canine sociability.
Each dog was given three minutes to find the treats, and as they did so, their behavior was videotaped and scored for the frequency and duration of different behaviors like jumping up at the researcher and making eye contact.
Researchers have identified a few genes that may be connected to dogs’ propensity to seek out and interact with humans.
Researchers claim to have identified a few genes that seem to be associated with dogs’ propensity to seek out and interact with humans.
Each dog received three transparent, sliding plastic lids with a treat inside each one. However, despite the dog’s pawing and nose-pushing attempts, one of the lids was fixed and immovable.
Now, the number of recipes isn’t what separates people and dogs. The number of genes shared by humans and dogs is similar, at around 20,000. Dogs have roughly the same number of genes spread across 39 chromosomes as humans do across 23 chromosomes. In a sense, both humans and dogs have recipe books with an equal number of dishes.
Given that humans and dogs have so many similar body parts that perform the same fundamental biological functions, this makes sense. They even share a variety of genetic illnesses, such as congenital heart disease, cancer, and blindness. Because of this, researchers have been using dogs to study human diseases.
Consequently, you might possess a crème brulee recipe that the dog’s cookbook lacks. Or you might have a recipe for oatmeal chocolate chip cookies when a dog has one for oatmeal raisin cookies. You are different from a dog (and, to a lesser extent, different from me) because of all these distinctions.
There are many different metrics to measure how similar two species are, so the percentage of DNA that humans and dogs share will vary. However, the team that sequenced the dog genome for the first time discovered that they could match about 73% of dog DNA to human DNA. They also discovered that nearly all of a dog’s genes are also present in humans.
The majority of these variations are brought on by the use of different letters in the recipes themselves or in the directions for using them. To put it another way, some variations are found in the DNA outside of the genes, which instructs a cell how frequently to read a gene, while others are found in the genes themselves.
FAQ
Do humans share DNA with dogs?
90% of our homologous genes are shared with our feline friends, compared to 82% with dogs, 80% with cows, 69% with rats, and 67% with mice [1]. Because the two species are so closely related, human and chimpanzee DNA are remarkably similar.
How much human DNA does a dog have?
Dogs are helpful animals to study human disease processes because they and humans share 84 percent of DNA. Particularly of interest to researchers are diseases that affect both humans and dogs.
What animal has closest DNA to humans?
Since the chimp genome was sequenced in 2005, scientists have known that humans and chimpanzees are the closest living relatives because they share 99% of our DNA.
Are human related to dogs?
According to a recent study, evolution shaped the genes in humans and dogs that relate to diet, behavior, and disease. The bond between dogs and humans is ancient and enduring.