Bacteria Found to Have Symmetrical DNA Signposts

Bacteria contain symmetry in their DNA signals that enable them to be read either forwards or backwards, according to new findings at the University of Birmingham which challenge existing knowledge about gene transcription.

In all living organisms, DNA code is divided into sections which provide information about a specific process. These must be read before the information can be used. Cells identify the start of each section using 'signposts', which scientists first identified in the 1960s.

It has always been assumed that these signposts enable genetic sequences to be read in a single direction. The new paper, published today in Nature Microbiology, however, shows that single-celled organisms have symmetrical DNA signposts. This means that the DNA code can be read in either direction.

"Most of the studies on gene signaling overlook the symmetry, but we think this is incredibly significant and represents a whole new level of regulating genes that has not yet been investigated," lead author Professor David Grainger explained.

The precise reasons for the two-directional reading are not yet clear and will require further investigation. One theory the team is considering is that it helps to avoid reading 'collisions' with other sequences.

Although the current study focuses mainly on bacteria, the team speculate that the signpost symmetry is likely to be found in humans, animals, and other organisms too. The next step for the research will be to investigate the phenomenon in yeast cells which more closely resemble human cells.