Dosage compensation: making 1X equal 2X.
Animals that have XX females and XY or XO males have differing doses of X-linked genes in each sex. Overcoming this is the most immediate and vital aspect of sexual differentiation. A number of systems that accurately compensate for sex-chromosome dosage have evolved independently: silencing a single X chromosome in female mammals, downregulating both X chromosomes in hermaphrodite Caenorhabditis elegans and upregulating the X chromosome in male Drosophila all equalize X-linked gene expression. Each organism uses a largely non-overlapping set of molecules to achieve the same outcome: 1X = 2X.
Meller
V H
VH
Dept of Biology, Tufts University, Medford, MA 02155, USA. vmeller@emerald.tufts.edu
D000818:Animals; D004303:Dosage Compensation, Genetic; D005260:Female; D008040:Genetic Linkage / Q000235:genetics; D006801:Humans; D008297:Male; D014960:X Chromosome / Q000235:genetics