逆转录的基因副本（逆转录复制体）已成为进化创新的重要来源。微小RNA（miRNA）是小而高度保守的RNA分子，其作为基因表达后转录的关键调节因子。miRNA的起源和后续演化已开始研究但尚未完全阐明。在本研究中，我们对通过逆转录复制的mRNA序列（逆转录的miR）的miRNA起源进行了全面的调查。我们鉴定出了17个起源于mRNA逆转录复制体的逆转录的miR。其中4个逆转录的miR具有在逆转录复制体序列内的新生起源，而13个逆转录的miRNA位于外显子区域并与宿主mRNA一起复制。我们发现逆转录的miR是灵长类特有的，包括五个在所有灵长类中保守的逆转录的miR和两个仅人类特有的miR。所有的逆转录的miR都有表达，具有预测和实验证实的目标基因，除了miR-10527。值得注意的是，逆转录的miR的目标基因参与关键的生物过程，如代谢过程、细胞信号传导和中枢神经系统神经递质的调节。此外，我们发现这些逆转录的miR通过靶向关键的癌症基因在癌症中发挥潜在的致癌作用，并在多种癌症类型中过度表达，包括肝细胞癌和胃腺癌。我们的发现表明mRNA逆转录是灵长类中产生新miRNA（逆转录的miR）的关键机制。这些逆转录的miR表达，保守，并具有重要细胞功能的目标基因，在癌症中起着重要作用。 © 2023 BioMed Central Ltd., Springer Nature的一部分。

Reverse-transcribed gene copies (retrocopies) have emerged as major sources of evolutionary novelty. MicroRNAs (miRNAs) are small and highly conserved RNA molecules that serve as key post-transcriptional regulators of gene expression. The origin and subsequent evolution of miRNAs have been addressed but not fully elucidated.In this study, we performed a comprehensive investigation of miRNA origination through retroduplicated mRNA sequences (retro-miRs). We identified 17 retro-miRs that emerged from the mRNA retrocopies. Four of these retro-miRs had de novo origins within retrocopied sequences, while 13 retro-miRNAs were located within exon regions and duplicated along with their host mRNAs. We found that retro-miRs were primate-specific, including five retro-miRs conserved among all primates and two human-specific retro-miRs. All retro-miRs were expressed, with predicted and experimentally validated target genes except miR-10527. Notably, the target genes of retro-miRs are involved in key biological processes such as metabolic processes, cell signaling, and regulation of neurotransmitters in the central nervous system. Additionally, we found that these retro-miRs play a potential oncogenic role in cancer by targeting key cancer genes and are overexpressed in several cancer types, including liver hepatocellular carcinoma and stomach adenocarcinoma.Our findings demonstrated that mRNA retrotransposition is a key mechanism for the generation of novel miRNAs (retro-miRs) in primates. These retro-miRs are expressed, conserved, have target genes with important cellular functions, and play important roles in cancer.© 2023. BioMed Central Ltd., part of Springer Nature.