Does Wolbachia interfere with dosage compensation

Organisms with male heterogametic (XX in females and XY in males) or female heteroga-metic (WZ in females and ZZ in males) sex-determining systems have different numbers of X chromosomes (or Z chromosomes) between males and females . To equalize the titers of X-linked (or Z-linked) gene expression between males and females, many organisms adopt two alternative processes: overexpression of X-linked genes in males or underex-pression of X-linked genes in females (Marin et al., 2000; Parkhurst and Meneely, 1994; Charlesworth, 1996). These mechanisms are collectively referred to as dosage compensation It is known that Drosophila, Caenorhabditis elegans, and mammals undertake dosage compensation In the lepidopteran insect B. mori, however, dosage compensation is absent, because Z-liked gene expression is twofold higher in males than in females (Suzuki et al ., 1998, 1999) . Therefore, in B. mori, males and females function normally despite the unequal amounts of Z-linked gene products between males and females

In D. melanogaster, the endosymbiotic bacteria Spiroplasma are known to cause male killing (Williamson and Poulson, 1979) . A male-specific protein complex (dosage compensation

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