||Fruit fly Drosophila melanogaster
||Drocco JA, Grimm O, Tank DW, Wieschaus E. Measurement and perturbation of morphogen lifetime: effects on gradient shape. Biophys J. 2011 Oct 19 101(8):1807-15. doi: 10.1016/j.bpj.2011.07.025. p.1808 left column 2nd paragraphPubMed ID22004733
|| St Johnston D, Driever W, Berleth T, Richstein S, Nüsslein-Volhard C. Multiple steps in the localization of bicoid RNA to the anterior pole of the Drosophila oocyte. Development. 1989 107 Suppl:13-9  Little SC, Tkacik G, Kneeland TB, Wieschaus EF, Gregor T. The formation of the Bicoid morphogen gradient requires protein movement from anteriorly localized mRNA. PLoS Biol. 2011 Mar9(3):e1000596. doi: 10.1371/journal.pbio.1000596.PubMed ID2483989, 21390295
||P.1808 left column 2nd paragraph: "Perhaps the best-suited biological gradient for quantitative studies is provided by the transcription factor Bicoid (Bcd), which controls anterior-posterior gene expression in the Drosophila embryo (refs 4,11). This gradient arises from maternally deposited mRNA at the anterior pole, within 3 h after fertilization, in a syncytial embryo 500µm in length (primary sources). During these first 3 h, the embryo undergoes 14 synchronous nuclear divisions, and cellularization begins after the last division. The Bcd gradient induces response genes, such as hunchback, at precise and reproducible positions within the embryo (refs 14,15)."