The vast majority of human DNA lies outside of the genes within the cells. Of this, recent work has discovered that 85% of these stretches of DNA appear to make RNA - which, in this case, has yet-to-be-determined functions.
“Today, scientists estimate that only 1.5 percent of the genome consists of genes.”
The lab investigates the remaining 98.5% - which (referencing similarly-scaled problems in cosmology) they call the 'Dark Matter' of the human genome.
“Much of the human genome is composed of intergenic sequence, the regions between genes. Intergenic sequence was once thought to be transcriptionally silent 'junk DNA', but it has recently become apparent that intergenic regions can be transcribed. However, the scope, nature, and identity of this intergenic transcription remain unknown. Here, by analyzing a large set of RNA-seq data, we found that >85% of the genome is transcribed, allowing us to generate a comprehensive catalog of an important class of intergenic transcripts: long intergenic noncoding RNAs (lincRNAs). We found that the genome encodes far more lincRNAs than previously known.”
“We believe that the regulatory noncoding RNAs that have been discovered are just the 'tip of the iceberg' in a set of important biology that we are far from understanding.”