my country's earliest "genetic" modification project began 5,000 years ago!

"The market is lined with pearls and jade, and every household is filled with silk and satin, competing in luxury." In "Looking at the Sea Tide·The Scenic Spots of the Southeast", the poet Liu Yong described the scene of Hangzhou in the Northern Song Dynasty, when every household was filled with silk and satin.

Silk is a vivid cultural name card of our country, and the long history has also nurtured a rich silk culture.

Zhou Yang, deputy director of the China National Silk Museum, said that as early as more than 5,000 years ago, the ancient ancestors living in the Yellow River Basin and the Yangtze River Basin realized the use of silk, began to domesticate silkworms, and tried to make woven fabrics with silk. Archaeological discoveries at the Qianshanyang Site in Huzhou, Zhejiang, and the Qingtai Village Site in Xingyang, Henan, also prove that silk appeared in my country more than 5,000 years ago.

A tiny silkworm opens up 5,000 years of silk culture

In the drizzle, the reporters visited the China Silk Museum, which is located beside the West Lake and at the foot of Yuhuang Mountain. The museum is built on the mountain, and it is even more quiet and profound in the sound of rain.

On the first floor of the museum, the "Jincheng: Chinese Silk and the Silk Road" themed exhibition features a row of miniature models showing the ancient people's silkworm breeding and silk weaving process. Guide Guan Qin introduced that these miniature models were based on the "Silkworm Weaving Picture" inscribed by Empress Wu of Emperor Gaozong of the Southern Song Dynasty, depicting the silk production process of mulberry planting, silkworm breeding, and weaving in the eastern Zhejiang area in the early Southern Song Dynasty.

"The life of a silkworm begins with a tiny egg. After hatching, it becomes a larva, then spins silk and makes a cocoon to become a pupa, and finally transforms into a moth with wings." Guan Qin said that while ancient ancestors were paying attention to and domesticating silkworms, they also mastered the laws of their growth and development, and summed up a set of production experience in the specific practice of silk weaving, which fully reflected the wisdom and technological creativity of the ancients.

In the exhibition of the Silk Expo, "bathing silkworms in the twelfth lunar month" is the starting point of silkworm breeding and reeling. "Bath silkworms" is a method used by the ancients to artificially eliminate inferior silkworms. Every twelfth lunar month, the ancients would bathe the silkworms to prepare for the hatching of the silkworms in the spring of the following year. It is also recorded in "The Exploitation of the Works of Nature" that the ancients often used natural dew bathing, lime bathing, salt water or brine bathing to bathe silkworms. This method can sterilize and disinfect, and can also screen out weak silkworms. In this way, the surviving silkworms will not waste mulberry leaves and will produce more silk.

Silkworm bathing model

As the busy Grain Rain season approaches, the silkworms eat and sleep, and it is time for them to grow up. Guan Qin told reporters that silkworms will experience four sleeps during their development, and they will molt every time they sleep. In the first three sleeps, the silkworms are still in the young silkworm stage and have poor resistance to low temperatures, so the silkworm mother will use a charcoal brazier to "warm the silkworms".

After the fourth sleep, or the "big sleep", the mature silkworms spin silk and make cocoons on the spinning apparatus. People will take the cocoons off the apparatus and peel off the loose and weak outer cocoon skin to facilitate reeling. "In order to extend the period of reeling, people will also add salt to store the cocoons to facilitate the preservation of the cocoons," said Guan Qin.

The miracle between warp and weft: the ingenious calculation hidden in silk

In the "Inspiration of Silkworms: Intangible Cultural Heritage Exhibition of Chinese Sericulture and Silk Weaving Techniques" at the Silk Museum, several large loom models attracted the attention of reporters.

Reporters and guides standing in front of the Song brocade loom

Exquisite and gorgeous silks are not just "purely handmade" by ancient weavers. The weaving process also has a strong "technological style" and is inseparable from these looms that are full of oriental wisdom and Chinese characteristics.

Guan Qin introduced that in the process of weaving silk, there are two types of weaving threads, "warp" and "weft", which are similar to longitude and latitude in geography. When a weaver sits on the loom, the silk thread perpendicular to his body is called the warp, which will not change at will during the weaving process. As the shuttle in the weaver's hand continues to add, it is the weft, and its thickness and color can be adjusted continuously as needed. When people get strands of white silk from silk cocoons, they must use a loom to weave the warp and weft together according to a certain pattern to get a piece of gorgeous silk.

In the center of the exhibition hall, there is a loom called "Five-star Brocade Loom", which imitates the loom principle of the Han Dynasty unearthed by archaeologists and is used to restore the "Five Stars Rising from the East" Han Brocade. "This loom can be called a 'computer' of the Han Dynasty, and its weaving process uses the principle of binary," said Guan Qin.

Five-star Brocade Loom

The five-star brocade is woven with five colors of red, yellow, blue, white and green. There are 84 heddles (devices on the loom that interweave the warp and weft), and each heddle has more than 10,000 silk threads. Every time the weaver operates the loom and lifts a heddle, one of the five colors of red, yellow, blue, white and green silk threads is on the top and four are on the bottom. If the silk thread above the weft is numbered "1" and the four below are numbered "0", it is equivalent to setting a binary code similar to a computer for the loom. In this binary context, a matrix with more than 9 million interweaving points is formed, and this matrix constitutes the "jacquard program" of the five-star brocade.

If the loom is compared to hardware, then jacquard is like software. As long as the loom is turned on, it is like turning on a computer with one click, and gorgeous silk will be produced from the machine continuously.

Zhou Yang, Deputy Director of China National Silk Museum:

The birth of silk, a chain of technological inventions

The China National Silk Museum is the world's largest silk museum, showcasing China's 5,000-year history and culture of silk. The museum houses historical relics related to silk from the Neolithic Age onwards, especially Han and Tang Dynasty fabrics unearthed along the Silk Road, Liao and Jin Dynasty objects from the northern grasslands, Song Dynasty costumes from the Jiangnan region, official products from the Ming and Qing dynasties, and modern cheongsams and landscape fabrics. Zhou Yang, deputy director of the China National Silk Museum, is a guest on this issue of "Science in Zhejiang Culture".

Q: What was the most critical scientific breakthrough in the invention of silk?

A: The most critical thing is the domestication of wild silkworms into domesticated silkworms. Domestication is the modification of the genes of wild silkworms through human intervention. This is a profound change in nature, and once changed, it cannot be reversed. All changes are made to meet the preset goals of humans.

This should be an extremely long and special domestication process. According to the research of the team led by Academician Xiang Zhonghuai of Southwest University, during this process, 354 loci of the wild silkworm's genes mutated, bringing about a series of changes in biological traits. For example, the domestic silkworm changed from the cold-blooded wild silkworm and could accept high-density feeding, with a significant increase in cocoon production and faster growth. Obviously, through domestication, humans have obtained more, larger and better cocoons, providing high-quality, stable and reliable raw materials for silk production.

Q: What are the early physical evidences that can truly explain the origin of silk?

Answer: The academic community generally believes that there are three cases.

In 1926, half a silk cocoon dating back 5,000 years was unearthed from the Xiyin Village site in Xia County, Shanxi Province, which is evidence of human use of silk cocoons; in 1958, a piece of silk dating back 4,200 years was unearthed from the Qianshanyang site in Huzhou, Zhejiang Province, which is evidence of the appearance of silk in the Yangtze River Basin; in 1983, silk fragments dating back 5,630 years were unearthed from the Qingtai Village site in Xingyang, Henan Province, which is evidence of the appearance of silk in the Yellow River Basin and is also considered to be the earliest silk fabric discovered in my country to date.

Q: Why is it said that the origin of sericulture and silk is essentially a scientific and technological invention?

Answer: Our ancestors planted mulberry trees and raised silkworms, let them spin silk and make cocoons, and skillfully wove the warp and weft to weave them into brocade. They also used printing, embroidery and other methods to present an imaginary fairyland and real nature on the fabrics.

During the birth of silk and the development of production technology, many inventions have been extended. For example, domesticating wild silkworms into domestic silkworms is an extremely difficult achievement in the history of biology. So far, only two insects have been successfully domesticated by humans: silkworms and honey bees. Using foot pedals as a mechanism to power and control the operation of silk reeling machines and plain looms was regarded as a Chinese invention by the famous Sinologist Joseph Needham, which had a great impact on the development history of loom structure. The most ingenious and important invention in silk weaving is to load special patterns on jacquard machines to control fabric patterns, which directly enlightened the programming design of early telegraphs and computers. Silk also had a very direct impact on papermaking and printing, two of my country's four great inventions. Silk produced primitive paper during the production process, and the woodblock printing technology of the Han Dynasty was the earliest color overprinting technology. In addition, silk has made great contributions to my country's traditional mathematics, physics, chemistry, biology and other fields.

"Chinese sericulture and silk weaving skills" are an integral part of China's cultural heritage and a cultural symbol recognized by the Chinese nation. This traditional manual production skill and related folk activities are still widely inherited in Hangzhou, Jiaxing, Huzhou, Jiangsu, Sichuan and other places.