A non-coding RNA (ncRNA) is an RNA molecule that is not translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. It is also likely that many ncRNAs are non functional (sometimes referred to as junk RNA), and are the product of spurious transcription.

Non-coding RNAs (ncRNAs) function to regulate gene expression at the transcriptional and post-transcriptional level. Some ncRNAs appear to be involved in epigenetic processes. They are shown to play a role in heterochromatin formation, histone modification, DNA methylation targeting, and gene silencing.

Coding RNAs generally refers to mRNA that encodes protein ① to act as various components including enzymes, cell structures, and signal transductors. Noncoding RNAs act as cellular regulators without encoding proteins ③.

Small RNAs (sRNAs) regulate gene expression post-transcriptionally by base pairing with the mRNA. The integration of sRNAs in feed-forward loops provides tight repression, guaranteed by the combination of transcriptional and post-transcriptional regulations.

Coding DNA refers to the DNA in the genome, containing for protein-coding genes while noncoding DNA refers to the other type of DNA, which does not code for proteins.

Eukaryotic gene expression is regulated during transcription and RNA processing, which take place in the nucleus, and during protein translation, which takes place in the cytoplasm. Further regulation may occur through post-translational modifications of proteins.

Introns are noncoding sections of an RNA transcript, or the DNA encoding it, that are spliced out before the RNA molecule is translated into a protein.

Coding and noncoding DNA are two components of organisms’ genome. Coding DNA are the DNA sequences which encode for proteins necessary for cellular activities. Noncoding DNA are the DNA sequences which do not encode for proteins. This is the difference between coding and noncoding DNA.

These small regulatory RNAs play a critical role in gene regulation via numerous mechanisms. The mechanisms by which small regulatory RNAs function include binding to protein targets, protein modification, binding to mRNA targets, and regulating gene expression.

CNCI analysis is a method to distinguish non-coding from coding transcripts by the traits of adjacent nucleotide triplets. It does not depend on known annotation files and can effectively predict incomplete transcripts and antisense transcripts, and transcript is noncoding RNA when score < 0.