The little toenail is divided into two halves, the scientific name is "piánzhǐ", also known as "compound nail" and "webbed nail". Medically, it is called petal nail or little toe complex, which means that the little toe nail is divided into petals instead of a whole piece. Biology believes that petaloid nail is an autosomal dominant trait and cannot be used as a specific symbol of a certain population. Western medicine believes that this is a foot disease, a human disease, regardless of race, many people will have this disease.

According to legend, more than 600 years ago, Zhu Yuanzhang was in charge of the world and decided to move Shanxi people with a large population to the south. Immigrants gathered under the big locust tree in Hongdong County, making it difficult to leave their homeland. The soldiers cut a knife on everyone's little toenail, so that they could recognize their ancestors and return to their ancestors in the future. However, those who have cracks or cracked toenails are relatives.

This sentence has been passed down to this day, and many families of Shanxi immigrants have repeated this story to their children from generation to generation.

However, we are young people who speak scientific truth. At first glance, this legend is full of loopholes. Nowadays, people all know that the wounds caused by knife cutting are not hereditary. How can the knife that was beaten more than 600 years ago have such great power that the wound can be passed down from generation to generation?

If it's really like the legend, will there be a scar on the stomach of a woman who has a caesarean section? It is hereditary to cut a knife carelessly, so why hasn't the foot binding passed down from generation to generation been passed down? Therefore, after identification, it is only a beautiful "rumor" that the knife cuts the toes and passes them on to future generations.

In 2005, the professor conducted a comprehensive study on the "Toe Legend" in genetics. The results show that the distribution of petaloid nail is decreasing from Shanxi to Henan, Jiangsu and Zhejiang to Jiangxi and Fujian. This shows that the distribution of petaloid nails in a certain area is indeed related to Shanxi immigrants. The frequency of petaloid nails decreases from Shanxi to southeast. This conclusion is consistent with the historical facts of immigration, that is, as far as immigrant areas are concerned, the farther southeast, the fewer immigrant areas there are.