Did Venter create life? Not really, say experts

Amit Bhattacharya | TNN

New Delhi: Are the bacterial cells created in J Craig Venter’s laboratories in the US actually synthetic life? After the hype and hoopla over the announcement of the world’s first “manmade living cells”, scientists are getting down to answering that question. And this is what most of them have to say: Venter’s team has achieved a stupendous technical feat, but the cells cannot be called synthetic.

Using an analogy from everyday life, what the team did is akin to completely reprogramming a computer, but not building one from scratch. Here’s why.

As the first step in the decadelong work, Venter and his researchers mapped the genome of a simple bacteria, Mycoplasma mycoides. Genome is the ‘brain’ of any cell and contains sequences of DNA which carry all the genetic information needed for the cell — and by extension, the organism — to function.

Like all living matter, the genome is made of chemicals. What Venter’s team did next is being hailed as a tour de force. It manufactured the M mycoides’ genome, step by step in the lab, using, in Venter’s words, “four bottles of chemicals”. This synthetic genome, identical in every way to the ‘original’ except for certain harmless ‘signatures’ the team put in to mark it as a builtin-the-lab version, was then inserted into another type of bacteria after the bacteria’s own genome had been sucked out.

Venter describes what happened next: “As soon as the genome goes into the cell, it starts making new proteins encoded in its DNA and converts it into a new synthetic species. It’s a completely synthetic cell now, it has replicated over a billion times. The only DNA it has now is the synthetic one that we made.”

In other words, the once the synthetic M mycoides genome is introduced in the bacterial cell, it transforms into an M mycoides. When it replicates, the off-springs too are M mycoides, carrying copies of the man-made genome. Venter believes, for all practical purposes, this is synthetic life. But other experts are saying that though the cell’s control station is artificial, the cell itself isn’t. Neither is it a new form of life —the artificial genome is an exact replica of a M mycoides genome.

Says Delhi University Vice-Chancellor Deepak Pental, himself a biotechnologist, “In this case, the bacterial cell is being seen as a shell, an envelope into which man-made genome is inserted. But the shell is much more than an envelope.” Nobel-winning British biologist Paul Nurse elaborates the point. In an conversation with BBC, he says, “Venter’s work is a major advance. But it’s not a creation of synthetic life...Creation of synthetic life would be to make an entire bacterial cell through chemicals.”

Nurse, Venter’s rival, believes creating an entirely new cell from scratch, though theoretically possible, would require a level of technology likely to be reached “long after we are dead”. He points out that in Venter’s method, there’s very little scope of deviating from nature’s script. “In an earlier attempt, Venter’s team got just one genetic ‘letter’ wrong — out of a million — and this cell simply didn’t function,” he says.

THESE CELLS AREN’T SYNTHETIC

Craig Venter's team created the genome of an M mycoides bacteria in the lab and inserted it into another type of bacteria

The recipient bacteria started behaving like an M mycoides. Its offspring too carried copies of the man-made genome

Venter says the cells are synthetic since they are controlled by genes made in lab
Other experts say that for any cell to be called synthetic, all its components should’ve been created artificially — perhaps possible in theory, but as yet technically impossible