This week scientists synthesize a chunk of the yeast genome.

I wasn't sure whether it would be feasible, but sometimes a project is just so exciting that you say,

yeah, I want to be part of this.

And researchers flying behind planes to measure emissions report a turbulent ride.

The most dominant indicator that we were in the plume was you could feel it in the seedier pants.

Plus tracking down HIV hidden in cells.

This is the Nature Podcast for March the 16th, 2017.

I'm Kerry Smith.

And I'm Adam Levy.

Okay. Over the past century, aviation has changed the way people travel around the world.

Unfortunately, it's also changing the world itself.

Flying is currently responsible for about 2% of all carbon dioxide emissions, and it's only expected to increase over the coming few decades. But carbon dioxide emissions only tell part of the

story. David Lee runs the Centre for Aviation, Transport and the Environment at Manchester Metropolitan University.

He explains that the particles planes emit can also have big effects.

First of all, at ground level, particles are obviously a big issue to do with local air quality

and human health. But at altitude, particles are involved in the formation of

contrails. Contrails are the white stripes of ice crystal clouds that you can sometimes see behind

aircraft. Sometimes they remain and they spread out and they form an ice crystal cloud formation called contral cirrus.

And we know that that formation of contral cirrus has a warming effect.

And on putting that in context with the other effects of aviation,

it's about the same order of magnitude of effect, the control series effect,

as the cumulative CO2 effect from the global fleet.

...