The present invention provides a nucleic acid such as a micro-RNA or a
micro-RNA precursor, having a novel sequence. The nucleic acid of the
present invention is useful for detecting the expression or a mutation of
a micro-RNA, separating cells, suppressing the expression of a gene
having a target sequence, screening for a substance that promotes or
suppresses a function of a micro-RNA, and diagnosing or treating a
disease caused by a mast cell abnormality, a disease caused by an
abnormality of mesenchymal stem cell proliferation or differentiation,
cancers, and a disease caused by abnormal proliferation of cells, tissue
hyperplasia or the like.