| A microRNA analysis pipeline was inherited and developed. MicroRNAs (miRNAs), a group of small non-coding RNAs, play important role during cell differentiation, growth, and death. Next-generation sequencing technologies such as Solexa generate millions of small RNAs sequence reads. The pipeline we developed can identify mature miRNAs from Solexa output. Also it predicts novel miRNAs by looking for similar alignment pattern from sequence reads that are not known miRNAs.;I argue that the characteristics of bristle organization are signatures of a Turing-type bifurcation. Turing periodic pattern emerges from a uniform background in reaction-diffusion process, in continua. In contract, a cellular system consists of a discrete array of cells. Further, proteins do not diffuse between cells. We argue that the intercellular actions mediated by membrane proteins trigger the bifurcation. Intercellular interations are more robust than diffusion which has only one direction. Intercellular interactions can be in any direction and between any species. We introduce a simple model to study pattern formation in such cellular arrays based on intercellular and intracellular actions. According to our pattern formation mechanism, periodicity in cell number is conserved through systems with different cell sizes.;I also studied the recurved bristles (sensory organs) on Drosophila wing margin. The expression levels of the achaete-scute complex protein determine the epidermal or neural fate of a pro-neural cell during the Drosophila development. At puparium formation, the concentrations of achaete-scute complex are nearly identical in all cells of the anterior wing except for some statistical noise. In wild-type flies, the development ends in a state where a recurved bristle grows out nearly every fifth cell. Recent experiments have shown that the frequency of recurved bristles can be changed by adjusting the mean concentrations of the zinc-finger transcription factor Senseless and the microRNA miR-9a. With reduced levels of miR-9a, mutant flies grow regular organization of recurved bristles, but with a lower periodicity. |
