| Autor: |
Nozawa M; Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan.; Research Center for Genomics and Bioinformatics, Tokyo Metropolitan University, Hachioji, Japan., Ikeo K; Center for Information Biology, National Institute of Genetics, Mishima, Japan.; Department of Genetics, SOKENDAI, Mishima, Japan., Gojobori T; King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering, Computational Bioscience Research Center, Thuwal, Kingdom of Saudi Arabia. |
| Abstrakt: |
Many organisms have a global mechanism for dosage compensation (DC) operating along the entire male X chromosome, which equalizes gene expression on the male X with that on the two Xs in females and/or on autosomes. At the initial stage of sex chromosome evolution, however, gene-by-gene (or localized) DC may also be necessary because the degeneration of Y-linked genes occurs independently at different times. We therefore tested whether the up-regulation of X-linked genes depends on the status of their Y-linked homologs, using the young sex chromosomes, neo-X and neo-Y, in Drosophila miranda. In support of the presence of gene-by-gene DC, the extent of up-regulation in males was indeed higher for neo-X-linked genes with pseudogenized neo-Y-linked homologs than for neo-X-linked genes with functional neo-Y-linked homologs. Further molecular evolutionary analysis also supports the idea that many individual neo-X-linked genes first acquired the potential for up-regulation, which then enabled the pseudogenization of neo-Y-linked homologs, without serious deleterious effects on male fitness. |
