In your opinion, how did the human hairless gene evolve?

Why people have no hair is a question that has not yet been determined. All I can say is that there are multiple viewpoints. The first point of view is that humans have mastered fire, so they no longer need hair. I think this is problematic. First of all, humans mastered fire relatively late. For example, Peking Man was about 700,000 years ago, and ape man hair at this time There are very few already. And simply due to climate change, other animals living in the tropics have not shed their hair so cleanly. What's more, ancient humans experienced multiple ice ages. Viewpoint 2: Human beings have experienced an aquatic stage in their development. Because mammals that shed their hair are trapped in the water, such as dolphins, walruses, and whales. Is it because humans have no hair because they lived in shallow seas? And this hypothesis can explain why humans have retained their hair. Because humans’ lungs store limited oxygen, even if they survive in shallow seas, their heads are above water, and all the hair on their heads is retained. Point 3: The need for sexual signals. This view is not considered mainstream, but I have seen it in many books. And I personally feel that this point of view can explain many problems that cannot be explained by other points of view. First of all, it can also be seen from animals other than humans that the higher the intelligence of animals, the more hedonic their sexual behavior is. This can be seen in monkeys and dolphins. Second, humans evolved from monkeys, and the sexual signal zone of monkeys is the buttocks, and the buttocks, as the erogenous zone, are naked and hairless. As a more advanced animal than monkeys, humans need stronger sexual signals, so their erogenous zones expand, exposing more and more places, and finally the whole body is exposed. Third, compared to monkeys, humans walk upright, and their buttocks are not as conspicuous as monkeys that walk on their stomachs. Another view is that women's breasts evolved by copying buttocks to make up for the lack of positive sexual signals. Therefore, the front of the human body also needs a bare area without hair to show the sexual model.