This paper presents a study on the phylogeny and classification of Wolbachia strains using wsp gene sequences. Wolbachia are intracellular bacteria that infect a wide range of arthropods and are associated with various reproductive phenotypes in their hosts, such as cytoplasmic incompatibility, parthenogenesis, and feminization. The authors cloned and sequenced the wsp gene from 28 Wolbachia strains, finding that this gene is highly variable and can be used to resolve phylogenetic relationships between different Wolbachia strains. Based on these sequences, the authors propose dividing the Wolbachia pipiensis clade into 12 groups and suggest that more groups may emerge as more sequence data becomes available. They also present a method for Wolbachia classification using group-specific wsp PCR primers, which allows for rapid typing of Wolbachia isolates without the need for individual gene cloning and sequencing. This system is expected to facilitate future studies on the distribution and biology of Wolbachia strains from large samples of different host species. The paper discusses the evolutionary significance of the wsp gene and its potential applications in understanding Wolbachia's biology and ecology.This paper presents a study on the phylogeny and classification of Wolbachia strains using wsp gene sequences. Wolbachia are intracellular bacteria that infect a wide range of arthropods and are associated with various reproductive phenotypes in their hosts, such as cytoplasmic incompatibility, parthenogenesis, and feminization. The authors cloned and sequenced the wsp gene from 28 Wolbachia strains, finding that this gene is highly variable and can be used to resolve phylogenetic relationships between different Wolbachia strains. Based on these sequences, the authors propose dividing the Wolbachia pipiensis clade into 12 groups and suggest that more groups may emerge as more sequence data becomes available. They also present a method for Wolbachia classification using group-specific wsp PCR primers, which allows for rapid typing of Wolbachia isolates without the need for individual gene cloning and sequencing. This system is expected to facilitate future studies on the distribution and biology of Wolbachia strains from large samples of different host species. The paper discusses the evolutionary significance of the wsp gene and its potential applications in understanding Wolbachia's biology and ecology.