The scientists in the Institute mainly use the mulberry silkworm (Bombyx mori) as a model organism to study fundamental questions in entomology and sericulture. In addition, the microsporidia (Nosema bombycis), a pathogen infecting the domesticated silkworm (B. mori), is another model organism for the scientists. There are several distinct but related research areas in the Institute.

1. The Silkworm Genome Project
In 2004, the Chinese and Japanese scientists sequenced whole genome of the domesticated silkworm (B. mori) by shotgun sequencing technique and opened the 6x and 3x genome sequences to public, respectively (Xia et al. Science 306: 1937-1940; Mita et al. 2004. DNA Res. 11: 27-35). This provides important research resources for the silkworm community. However, the draft genome sequence is not sufficient to know the silkworm genome structure and to efficiently isolate the genes of interest by positional cloning strategy. Now, the scientists from both China and Japan are assembling the updated silkworm genome sequence using the information of BAC ending sequences and linkage map markers. The new assemble of the silkworm genome sequence will be available at the SilkwormBase soon.

2. Functional Genomics of the Domesticated Silkworm
The silkworm genome sequencing project has provided the vast wealth of data to describe the gene (and protein) functions and interactions. With the whole genome sequence, the scientists in the Institute have designed and constructed a genome-wide microarray with 22,987 70-mer oligonucleotides covering the presently known and predicted genes in the silkworm genome, and surveyed the gene expression in 10 representative sample types (Xia et al. 2007. Genome Biol. in press). At the same time, they are investigating the temp-spatial expression patterns of the silkworm genes using proteomic and the functions of the genes in special metabolic and signaling transduction pathways.

3. The Genetics and Breeding in the Domesticated Silkworm
The Institute has long history (more than 60 years) of the study on genetics in the domesticated silkworm and of conservation of the domesticated silkworm stocks. More than 600 precious silkworm strains and mutants are maintained in the Institute. The scientists in the Institute have discovered many precious morphological mutants, such as white egg 5 (w-5), excessive grey egg (gr-r), etc. Most of which have been mapped to the classical linkage groups. As China is the biggest country of silk production in the world, the scientists have made much effort improving silkworm productivity and bred 3 new silkworm varieties.

4. The Microsporidia Genome Project
The microsporidian Nosema bombycis is a pathogen that infects the domesticated silkworm, causing pebrine disease. This disease is the key factor obstructing the developmental progress of sericulture in China. The scientists in the Institute are investigating the pathology of this disease and trying to develop new approaches to preventing the spread of this pathogen in sericultural practice. To efficiently reduce the effect of the microsporidian on sericulture and understand the mechanism of the parasite-host interaction, the scientists in the Institute are sequencing the genome of Nosema bombycis. The data will be open to public soon.

5. The Evolutionary Genetics of the Domesticated Silkworm
The domesticated silkworm (B.mori) was domesticated from the wild silkworm (Bombyx mandarina) about 5,000-10,000 years ago. In the Silk Road era about 2,000 years ago, the domesticated silkworm played a crucial role in globalization. It is generally thought that the domesticated silkworm initially originated from China and then spread to Europe, Japan, and other countries. Currently, the wild silkworm exists in fields. This provides a good opportunity for studying the genetics of silkworm domestication by comparing the genomes of the domesticated and wild silkworms. Long term artificial selection of domestication and breeding has made the domesticated silkworm quite different from the wild silkworm in both morphological and behavioral traits. What is the genetic basis of differences in morphology and behavior between the domesticated and wild silkworms? Which changes of genes made the domesticated silkworm from the wild silkworm? Did the artificial and natural selections leave the signatures in the corresponding genomes? If so, are they different from each other? Now, the scientists in the Institute are trying to address the above questions at molecular level.