ZHENGZHOU, CHINA—Xinhua reports that researchers led by Zhao Feng of the China National Silk Museum developed a technique called enzyme-linked-immunosorbent assay (ELISA) to detect the presence of silk in carbonized residue in a burial at the Neolithic Wanggou site in central China. The fabric is thought to have been used to wrap the body before it was placed in a silkworm pupa-shaped coffin for burial. Zhao thinks the shape of the coffin may have been intended to evoke rebirth after death in the same manner that a silk moth breaks through its cocoon. Gu Wanfa of the Zhengzhou Municipal Research Institute of Cultural Relics and Archaeology explained that the fabrics at Wanggou indicate that silk production was well developed in China between 5,300 and 5,500 years ago. Examination of the sample with an electron microscope revealed fine yarns woven with four-warp twisted rods, and the yarns had been dyed before they were woven into fabric, which was then “cooked” to prevent the dye from fading, Gu added. To read about a second-century B.C. silk topographical map recovered from a tomb in southeastern China, go to "Mapping the Past: Han Dynasty Map."