There are more and more strange-looking dogs, some even look like aliens. Why is this happening?

There are many kinds of pet dogs nowadays, with strange appearances, some are big, some are small, and can even fit in the palm of your hand. And now the plush puppets are becoming more and more exquisite. It is difficult to distinguish the real ones from the fake ones when these plush puppet dogs are mixed with real dogs.

It is said that dogs are domesticated from wolves. Why do many dogs today no longer look like wolves? Scientifically speaking, is it due to reproductive isolation or the result of species evolution? Let's discuss it together.

First, let's talk about the predecessor of the dog - the wolf

Humans and wolves are both mammals, and both benefited from the restart of species after the extinction of dinosaurs. 65 million years ago, with the end of the dinosaur era, the earth's environment changed greatly. In order to adapt to the new climate and environment, animals and plants changed a lot, and mammals were able to emerge and gradually became the masters of the earth.

Over the next 10 million years, the Cenozoic Era slowly opened, and the common ancestor of modern carnivores appeared. Scientific research shows that an animal called Maltese is the common ancestor of carnivores such as cats, dogs, bears, and mustelids, and it gradually differentiated during the long process of evolution.

Evolution took tens of millions of years until wolves began to appear between 10 and 8 million years ago, along with a large number of primates, including the ancestors of chimpanzees and humans. Over the next several million years, these wolves evolved into gray wolves, dire wolves, coyotes, red wolves, etc. Due to differences in migration and survival abilities, the dire wolves, which were larger in size and stronger and specialized in hunting large animals, became extinct.

There are many types of wolves now, mainly gray wolf, red wolf (American red wolf), coyote (jungle wolf), jackal (African jackal), red wolf (Asian jackal), Antarctic wolf (Fukushima wild dog), South American wolf (maned wolf), etc. Strictly speaking, wolves and jackals both belong to the Canidae family, but wolves belong to the authentic Canis gray wolf species, while jackals belong to the Caninae subfamily of the genus Cullus and have 11 subspecies.

From this, we can see that in evolution, the wolf's bloodline is still relatively pure, while dogs are domesticated from gray wolves.

There is solid evidence that dogs evolved from wolves

The predecessor of the dog is the gray wolf, which is a typical example of human intervention in species evolution. Early ancient humans mainly relied on hunting to fill their stomachs, but sometimes they would keep live animals in captivity for emergency use.

In the process of capturing wolves and raising them in captivity, people discovered that these animals were very intelligent and were able to build relationships and interact with humans. Gradually, they domesticated these animals to become hunting assistants or helpers in guarding the home.

The process of wolf turning into dog is very long. Wolf nature is hard to change. It is not achieved overnight. It took thousands or even tens of thousands of years of domestication for wolf to gradually turn into dog. Now there are many kinds of pet dogs. This is the result of human society gradually moving towards a well-fed society. Of course, at first, the "well-fed society" was only for a few nobles. After they had enough food all day, they gradually developed the custom of raising dogs as pets.

The early saying that wolves evolved into dogs was mainly based on some archaeological analysis and inheritance, and there was no reliable evidence. The development of genetics has provided solid evidence for the legend that dogs evolved from wolves. In 2005, humans first deciphered the canine genome. Scientists conducted DNA analysis on dogs from Europe, Asia, Africa, and America and found that all dogs in the world have similar gene series.

These genes are highly similar to the wolf's gene series. Both dogs and wolves have 39 pairs of chromosomes, and the genome similarity is as high as 99%. In particular, the genome similarity with the gray wolf is as high as 99.96%. Just as humans can use DNA testing to determine parent-child or blood relationships, scientific evidence proves that all dogs in the world are derived from gray wolves.

Scientists believe that the genetic difference between wolves and dogs requires at least 50,000 years of evolution and change to form. When did wolves become dogs? There are still some differences in this research. According to some archaeological excavations, it is basically determined that wolves have become dogs and become friends of humans 14,000 to 16,000 years ago.

By analyzing hair samples from 500 dog breeds around the world, Swedish scientists discovered that all dogs carry the same gene pool, and that East Asian dogs have more genetic variations. Therefore, they believe that the ancestors of modern dogs around the world are likely to have originated in East Asia. This result was published in the journal Science.

The study pointed out that about 15,000 years ago, human tribes in the area of ​​present-day China trained wild wolves into domestic dogs, which became the ancestors of the world's domestic dogs. Later, with the migration of humans, these domestic dogs were brought to various continents and differentiated into different breeds.

But a scientific team collected 18 canine fossils from Argentina, Belgium, Germany, Russia, Switzerland and the United States and extracted mitochondrial DNA from them. Among them, the dog skull fossil discovered by paleontologists from the Royal Academy of Sciences of Belgium in the Guyet Cave is 31,700 years old, and some fossils can be traced back to 36,000 years ago.

Many other scientists have also pointed to the emergence of dogs in an even more ancient period, so it can be determined that the domestication of dogs was as far back as 16,000 years ago. Moreover, this domestication could not have been achieved overnight, and it required gradual changes over tens of millions of years. Therefore, scientists believe that humans began to domesticate gray wolves at least 50,000 years ago, and some scientists have traced this time back to 100,000 years ago.

100,000 years ago, human ancestors were still concentrated in Africa. If dogs were really domesticated in that era, then these gray wolves that had not yet become dogs must have left Africa about 50,000 to 100,000 years ago as humans migrated to various parts of the world.

Why are there such big differences between dogs and wolves today, and why are there so many varieties?

Now, it is believed that dogs all over the world originated from East Asia. After 14,000 to 15,000 years of domestication, more than 400 species of dogs have gradually emerged, each with unique coat color and habits, and large differences in size. However, the ancestor of dogs, the wolf, has not changed much. What is the reason?

Research shows that this difference in change may be caused by two reasons, one is natural and the other is man-made.

The natural reason is that there are some special sequences in the dog's DNA. These DNA sequences are particularly easy to be freed, and often the whole segment is integrated from one part of the DNA chain to another. Compared with human DNA, dog's DNA often has repeated fragments, which can easily lead to genetic mutation.

This unique sequence of DNA fragments is called SINEC_Cf. This fragment will break away from the DNA chain and then attach to a gene, thereby changing the expression of this gene. However, this change is safe and benign. The places where the SINEC_Cf fragments attach are usually some genes that control the dog's appearance. There are only about 50 genes that control the dog's hair, body shape, body length, hair length and other physical characteristics. Compared with the nearly 20,000 genes of dogs, the proportion is extremely small, so it will not change the genetic basis of dogs.

In this way, more and more dogs with more diverse appearances are appearing, but they still all belong to the dog species.

Since dogs evolved from wolves, why do they have this mutable gene while wolves don't? I think this is probably related to human domestication. During the domestication process, people selected wolves that were easier to domesticate and "obedient" and better able to adapt to the environment. During the domestication process, the food source and structure of dogs also changed significantly. Therefore, during the long domestication process, genes changed in the direction of human needs under human intervention.

Some scientists have studied how human selective breeding affects the dog's genome and found that changes in food intake can also cause mutations in dog genes. For example, a group of scientists sequenced the entire genome of 60 dogs representing 14 different breeds and found that 10 of the genes were related to the digestion of fat and starch. Compared with wolves, dogs carry extra copies of the amylase gene, which improves the intestinal absorption and conversion function of starch. This is evidence that human domestication of dogs has led to genetic changes in dogs.

The various appearances of dogs today are mainly the result of human selection. Humans domesticated wolves according to their own needs, so they would purposefully select their offspring. For example, the main function of dogs in ancient times was to serve as hunting assistants and guard houses, so when selecting and breeding, they would generally choose offspring with larger bodies and more flexible and brave temperaments.

As society develops and changes, people have more and more functional requirements for dogs. In addition to being pets for people with extra food at home, dogs are also required to take on functions such as drug detection, rescue, guide, hunting, family companionship, and shepherding. In this way, each party can get what they need in the selection and breeding of their offspring.

Especially for pet dogs, some people like big ones, some like small ones, some like long-haired ones, some like short-haired ones, some like white ones, some like black ones, some like spotted ones, some like wrinkled ones, etc. Therefore, those dog breeding experts will deliberately select and breed the puppies born by dogs towards the breeds that people like and need.

After many long-term breeding and selection generations, the dogs have become smaller and bigger, the long-haired ones have become longer and the short-haired ones have become shorter, the wrinkled skin and wrinkled heads have become more and more weird, and there are more and more dogs of various colors and body shapes, forming the current large and colorful dog group.

With the advancement of science and technology, genetic engineering has increasingly entered our lives, and of course it will also affect the modification of dogs. However, the current gene editing and transcription technology is still more at the stage of plant modification, and artificial genetic modification of animals is still very cautious. Therefore, the current strange appearance of dogs is mainly the result of long-term artificial breeding.

This also strongly proves that the survival of the fittest is the basic law of natural evolution, and that the evolution of species is closely related to environmental influences. However, the evolution of dogs is much faster due to human intervention.

What do you think about this? Welcome to discuss, thank you for reading.

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