Study finds ‘dark matter’ DNA is vital for rice reproduction
Credit: OIST

Researchers from the Okinawa Institute of Science and Technology Graduate University (OIST) have shed light on the reproductive role of ‘dark matter’ DNA – non-coding DNA sequences that previously seemed to have no function.

Their findings, published today in Nature Communications, have revealed that a specific non-coding genomic region is essential for the proper development of the male and female reproductive organs in rice.

“Rice is one of the major global crops and is the staple food in many countries, including Japan,” said Dr. Reina Komiya, senior author of the research paper and associate researcher from the OIST Science and Technology Group. “Further research into how these genomic regions affect plant reproduction could potentially lead to increased productivity and more stable yields of rice.”

Many previous developmental studies have focused on genes – the sections of DNA that provide instructions for making proteins. But in complex creatures like plants and animals, a large fraction of the genome – typically between 90-98% – doesn’t actually code for proteins.

The vast expanse of this ‘junk DNA’ has long puzzled biologists, with many dubbing it the ‘dark matter’ of the genome. But recent research suggests that many of these non-coding genomic regions may have a function after all, giving rise to non-coding RNA.

Scientists have now identified numerous types of non-coding RNA, ranging from small molecules only 20-30 nucleotide bases in length to long molecules of over 200 nucleotides. Although studies show that non-coding RNA plays a vital role in the regulation of gene expression – the process where a gene’s instructions are used to make RNA or protein – the precise function of each specific non-coding RNA remains poorly understood.

Dr. Komiya is particularly interested in reproduction-specific RNAs. “These are non-coding RNAs that are produced as the reproductive system forms. I wanted to uncover what role they play in the development of stamens and pistils, the male and female reproductive organs in plants.”