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A nested gene is a gene whose entire coding sequence lies within the bounds (between the start codon and the stop codon) of a larger external gene. The coding sequence for a nested gene differs greatly from the coding sequence for its external host gene. Typically, nested genes and their host genes encode functionally unrelated proteins, and have different expression patterns in an organism. There are two categories of nested genes: * genes nested within an intron of a larger gene * genes which lie opposite the coding sequence of a larger gene == Nested intronic genes == A nested intronic gene lies within the non-coding intronic region of a larger gene, and occurs relatively frequently, especially in the introns of metazoans and higher eukaryotes. Because only eukaryotic DNA contains with intronic regions, this type of gene does not occur in bacteria or archaea.〔Kumar, Anuj (Sept 2009). "An Overview of Nested Genes in Eukaryotic Genomes". ''Eukaryotic Cell'' 8 (9): 1321-1329.〕 The human genome contains a relatively high proportion of nested intronic genes. It is predicted to contain 158 functional intronic nested genes, with an additional 212 pseudogenes and three snoRNA genes nested in intronic regions. These genes seem to be distributed randomly across all chromosomes, and the majority code for proteins that are functionally unrelated to their host genes.〔Yu, P., D. Ma, and M. Xu. (2005). "The SLT2(MPK1) MAP kinase is activated during periods of polarized cell growth in yeast." ''EMBO J.'' 15: 83-91.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nested gene」の詳細全文を読む スポンサード リンク
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