Thousands of genes that lie within our DNA do everything from control the colour of our eyes to our risk of disease and now Kiwi scientists have just helped reveal how masses more are likely to play an intriguing functional role in our bodies.
A landmark study just published in major scientific journal Nature, co-authored by Massey University researchers, effectively doubles the estimate of known functional genes in humans.
What these mysterious genes, previously thought to serve no biological role, do within us poses a huge new task for scientists.
The new study investigated genes of what are called long non-coding RNAs (ribonucleic acids), to assess whether or not they were being expressed in human cells and tissues and have a function after all.
RNAs are well known to carry information of transcribed genes of our genome, to be used as the building plan for proteins, the main actors in our cells.
However, many RNAs do not get translated into proteins, and for most of those non-coding RNAs, their functionality has been debated by scientists.
The team of international researchers produced a comprehensive atlas of 28,000 long non-coding RNA molecules and summarised for the first time their expression pattern in the major human cell types and tissues and found evidence of evolutionary selection and links with major diseases.
By intersecting this atlas with genomic and genetic data, the results suggest that 19,175 of these RNAs may be functional, hinting that there could be as many, or even more, functional non-coding RNAs than the approximately 20,000 protein-coding genes in the human genome.
Further, nearly 2000 of them had involvement in diseases and other genetic traits.
"There are many elements in our genome that we do not completely understand yet," said study co-author Dr Sebastian Schmeier, of Massey's Institute of Natural and Mathematical Sciences.
"Uncovering what they are exactly doing in our cells will be the next great challenge."
To date, several long, non-coding RNAs have been implicated in many important biological processes as well as diseases, including cancer.
The data generated in this study provides a platform for selecting additional long non-coding RNAs for further targeted studies.
Schmeier and his PhD student and study co-author Elena Denisenko were involved early on to investigate mutations in these genes.
The research was conducted as part of a worldwide collaborative project FANTOM, which aims to identify all functional elements in mammalian genomes.
"The improved gene models and the broad functional hints of human long non-coding RNAs derived from this atlas could serve as a Rosetta Stone for us to experimentally investigate their functional relevance as part of our ongoing work for the upcoming edition of the FANTOM consortium," co-author Dr Piero Carninci said.
"We anticipate that these results could further push the boundary of our understanding of the functions of the non-coding portion of our genome."