I haven’t spent much time outside the confines of the conference – apart from the sun-drenched stroll between the convention centre and another venue, the Sheraton, about a mile away.

So yesterday I thought, enough is enough. I went for a run over the Benjamin Franklin bridge with Neil Gussman, PR guy for the Chemical Heritage Foundation, and US army sergeant.

The run was amazing, the pedestrian bridge is much higher than the cars and the cars are much, much, much higher than the Delaware river. If you need to escape the city, you could do a lot worse than this towering piece of metal engineering.

Today I took another trip to CHF, to check out their new, and very impressive, gallery. It’s still under construction, but the floor-to-ceiling interactive periodic table installment (made in part by he of the Periodic Table Table fame, Theo Gray) is already in place. It is awesome. Videos run for each element, and the whole thing cascades from the huge 2-storey ceiling to the floor on a massive array of TV screens.

The new galleries are also hosting a travelling art exhibit, molecules that matter. This is a collection of artists representations of 10 selected molecules that have influenced society in the past 100 years. Apparently the choice of molecules upset some staunch organic chemists. I can’t see why. You should pop over and see if you’re getting cabin fever in the conference.

I haven’t spent much time outside the confines of the conference – apart from the sun-drenched stroll between the convention centre and another venue, the Sheraton, about a mile away.

So yesterday I thought, enough is enough. I went for a run over the Benjamin Franklin bridge with Neil Gussman, PR guy for the Chemical Heritage Foundation, and US army sergeant.

The run was amazing, the pedestrian bridge is much higher than the cars and the cars are much, much, much higher than the Delaware river. If you need to escape the city, you could do a lot worse than this towering piece of metal engineering.

Today I took another trip to CHF, to check out their new, and very impressive, gallery. It’s still under construction, but the floor-to-ceiling interactive periodic table installment (made in part by he of the Periodic Table Table fame, Theo Gray) is already in place. It is awesome. Videos run for each element, and the whole thing cascades from the huge 2-storey ceiling to the floor on a massive array of TV screens.

The new galleries are also hosting a travelling art exhibit, molecules that matter. This is a collection of artists representations of 10 selected molecules that have influenced society in the past 100 years. Apparently the choice of molecules upset some staunch organic chemists. I can’t see why. You should pop over and see if you’re getting cabin fever in the conference.

I haven’t spent much time outside the confines of the conference – apart from the sun-drenched stroll between the convention centre and another venue, the Sheraton, about a mile away. So yesterday I thought, enough is enough. I went for a run over the Benjamin Franklin bridge with Neil Gussman, PR guy for the Chemical Heritage Foundation, and US army sergeant.

The run was amazing, the pedestrian bridge is much higher than the cars and the cars are much, much, much higher than the Delaware river. If you need to escape the city, you could do a lot worse than this towering piece of metal engineering.

Today I took another trip to CHF, to check out their new, and very impressive, gallery. It’s still under construction, but the floor-to-ceiling interactive periodic table installment (made in part by he of the Periodic Table Table fame, Theo Gray) is already in place. It is awesome. Videos run for each element, and the whole thing cascades from the huge 2-storey ceiling to the floor on a massive array of TV screens.

The new galleries are also hosting a travelling art exhibit, molecules that matter. This is a collection of artists’ representations of 10 selected molecules that have influenced society in the past 100 years. Apparently the choice of molecules upset some staunch organic chemists. I can’t see why. You should pop over and see if you’re getting cabin fever in the conference.

University of Massachusetts, Worcester

A biologist despairs over the difficulty of demonstrating heritability of chromatin states.

Chromatin, the packaged bundles of protein and DNA that make up eukaryotic genomes, is widely believed to be a carrier of ‘epigenetic’ inheritance — that is, heritable information not encoded by DNA. In multicellular organisms, the chromatin of mother and daughter cells is generally of similar shape, exposing similar regions of DNA for expression. And chromatin regulators often seem to be required for epigenetic states to be inherited. But there is a problem. It is possible that some other information carrier is inherited, and then directs chromatin regulators to re-establish a functional state.

One purported example of chromatin inheritance comes from yeast, which seem to ‘remember’ prior growth conditions. Galactose-naive yeast induce genes for Gal enzymes slowly; those whose recent ancestors experienced galactose induce them much faster. Because this ‘memory’ requires certain chromatin regulators, it has been suggested that it provided evidence for a heritable chromatin state.

Zacharioudakis et al. investigate this idea using heterokaryons, fused pairs of yeast cells that have mixed cytoplasmic contents but maintain separate nuclei. By inducing memory in one yeast and seeing speedy GAL1 expression in the other, they show that memory of galactose is transferable through cytoplasm (I. Zacharioudakis et al. Curr. Biol. 17, 2041–2046; 2007). Thus, the chromatin state around the GAL1 gene cannot be the heritable factor, and the authors further identify the probable inheritance factor as a soluble enzyme.

These results demonstrate the difficulty of proving that any example of epigenetic inheritance is due to inheritance of chromatin state per se. One wonders whether any chromatin state will ever be proved to be heritable, given the difficulty of proving the absence of another information carrier.