The human genome contains ca. 3.2 billion base pairs, yet only about 2% codes for genes. The remaining 98% is junk DNA (I prefer the term 'satellite DNA').
However, new evidence shows something interesting: 85.2% of the genome is transcribed to functional RNA molecules:
"The researchers (...) identified thousands of previously unknown, unique RNA sequences. (...) Among the RNA transcribed by the DNA outside of genes, the UCSF researchers identified thousands of previously unknown RNA sequences of a type called lincRNA."
"lincRNA" means "Long, intergenic non-coding RNA"; long (> 200 base pairs) transcripts found in the DNA between genes.
The function of those transcripts is not yet fully understood, but the investigators noticed this:
"Furthermore, these lincRNAs are strongly enriched with intergenic sequences that were previously known to be functional in human traits [SNPs] and diseases [cancer]."
Ergo, not only does it show that DNA is definitely not a few genes surrounded by thousands of non-functional sequences, but it does also demonstrate that there could be a causality between human health, phenotype and our satellite DNA.
I hope that future research will focus on the link between DNA and diseases, in order to find and apply new therapies to cure these diseases.
What do you think?
Sources:
Griffiths, A.J.F. et al. (2012), "
Introduction to Genetic Analysis,
10th Edition", Freeman/Macmillan, pp. 312-315
DNA found outside genes plays largely unknown, potentially vital roles: Thousands of previously unknown RNA molecules identified
Hangauer, M.J., Vaughn, I.W., McManus, M.T. (2013), "Pervasive Transcription of the Human Genome Produces Thousands of Previously Unidentified Long Intergenic Noncoding RNAs",
PLoS Genetics 9(6), e1003569.