Here's proof of how far we've come in science - in a world-first, researchers have recorded up-close footage of a single DNA molecule replicating itself, and it's raising questions about how we assumed the process played out.
The real-time footage has revealed that this fundamental part of life incorporates an unexpected amount of 'randomness', and it could force a major rethink into how genetic replication occurs without mutations.
"It's a real paradigm shift, and undermines a great deal of what's in the textbooks," says one of the team, Stephen Kowalczykowski from the University of California, Davis.
"It's a different way of thinking about replication that raises new questions."
The DNA double helix consists of two intertwining strands of genetic material made up of four different bases - guanine, thymine, cytosine, and adenine (G, T, C and A).
Replication occurs when an enzyme called helicase unwinds and unzips the double helix into two single strands.
A second enzyme called primase attaches a 'primer' to each of these unravelled strands, and a third enzyme called DNA polymerase attaches at this primer, and adds additional bases to form a whole new double helix.
You can watch that process in the new footage below:
The fact that double helices are formed from two stands running in opposite directions means that one of these strands is known as the 'leading strand', which winds around first, and the other is the 'lagging strand', which follows the leader.
The new genetic material that's attached to each one during the replication process is an exact match to what was on its original partner.
More:
http://www.sciencealert.com/dna-replication-has-been-filmed-for-the-first-time-and-it-s-stranger-than-we-thoughtNever did think it was as neat a process as the textbooks say.
