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Some of our finest [ about ] Approved Articles Developed Articles (over 700) Share your knowledge. It's a way to achieve immortality. —Often attributed to the Dalai Lama Article of the Week [ about ] In living cells, genes are expressed via a messenger RNA (mRNA) which participates in the synthesis of proteins. In turn, the catalytic activities of proteins decide many of the properties of a cell, that is, its outward phenotype. RNA interference (RNAi) is a process that inhibits the flow of genetic information to protein synthesis, which normally proceeds from deoxyribonucleic acid (DNA) to messenger ribonucleic acid (mRNA) to proteins - a process known as gene expression (see figure, top right). mRNA, a single-stranded polymer, is the key molecule whose sequence of nucleotides transports the information encoded in DNA to regions of the cell where that DNA-genetic information is used for synthesizing proteins. Understanding that flow of information is necessary for understanding the RNAi mediated feedback loops that inhibit gene expression. Specifically, RNAi is a mechanism in eukaryotic cells that is triggered when such cells are exposed to certain double-stranded ribonucleic acid (dsRNA) molecules. The process has been detected in many organisms, including animal, plant and protist cells. The distinguishing characteristic of RNAi is destruction of mRNA molecules that share at least some of the sequence characteristics of dsRNA trigger molecules to which the cells have been exposed. RNAi has important biological roles in gene regulation and in protection of organisms against genetic parasites such as viruses and transposons. [more...] New Draft of the Week [ about ] Palatalization denotes several processes of assimilation in phonetics and phonology, by which the articulation of a consonant is changed under the influence of a preceding or following front vowel or a palatal or palatalized consonant. This is especially likely to occur with the palatal approximant [j]. As a general term, palatalization can cover various different phonetic and phonological processes such as phonological palatalization, phonetic palatalization, assibilation, and coronalization. The term 'palatalization' is sometimes used by European linguists (German Palatalisierung) to refer to a type of vowel mutation more commonly referred to as i-umlaut (UK: i-mutation). The French term mouillure (German Mouillierung) is another word for (phonemic) palatalization. [more...]