Yesterday was the first day of AbSciCon 2017 in Mesa, Arizona.
Phoenix is not my favorite town; it’s got all the brutal heat (and then some) that Tucson gets, without a tenth of Tucson’s charm. That said, it’s been fairly pleasant so far, only getting into the 80’s yesterday. The hotel restaurant is pretty lame, but there is decent food about a ten-minute walk away.
Yesterday started with a bizarre plenary talk about planetary protection. This is a big deal in the astrobiology community, the concern that sending probes to potentially habitable worlds such as Europa and Enceladus could contaminate them with Earth life. It’s also a harder problem to solve than it sounds like, partly because advanced electronics of the sort that are likely to run a probe don’t get along well with the things we typically use to sterilize equipment: bleach, extreme heat, radiation, and the like. The talk used a real-time interactive system, allowing the speaker to ask a question and display the results on the screen in real time. Multiple choice questions displayed as bar graphs, fill-in-the-blanks as word clouds, both changing from second to second as new answers came in.
It’s a cool technology, but overuse made it a little silly by the end. One problem is that, being the first morning of the conference, most people didn’t yet know the wifi password, so only a subset of the audience could participate. The questions started off interesting but devolved into opinions about other people’s opinions (What one word describes what policy makers think when they hear ‘contamination’?). It reminded me of a `90’s website where the designer got excited about being able to animate text. Kind of fun, especially when someone figured out they could submit emoji in their answers, but I didn’t learn much about planetary protection beyond ‘it’s complicated’ (and nobody knew that, right?).
Yesterday afternoon was the Major Transitions session I hosted with Will Ratcliff and Eric Libby. Topics ranged from origins of life to the evolution of intelligence, covering most of the major transitions (for some reason, eusociality never seems to be represented at these meetings…haven’t astrobiologists read Ender’s Game?).
Harrison Smith talked about a computational model of a non-nucleic acid inheritance system. This system can be studied in laboratory experiments, but such experiments are slow, limiting the number of independent populations and experimental conditions that can reasonably be studied. Computational models largely overcome this limitation, and when they are based on well-understood physical processes, they allow realistic exploration of large parameter spaces.
We had a pair of RNA-world talks, by Andrew Tupper and Ryo Mizuuchi. Both dealt with issues related to cooperation and conflict in prebiotic systems. In both cases, spatial structure is key to preventing the cooperative system from being overwhelmed by cheaters, a familiar theme in studies of the evolution of cooperation.
The best-attended talk was by Dawn Sumner on the origins of photosynthesis. Microbial samples from Lake Vanda in Antarctica included Melainabacteria closely related to cyanobacteria. Their genomes included genes related to phototrophy, suggesting that these bacteria are capable of photosynthetic growth. Phylogenetic reconstructions including the newly identified bacteria shed light on the probable role of horizontal gene transfer in the evolution of photosynthesis.
Kimberly Chen presented her recent results on the genetics underlying the shift to a multicellular life cycle in Chlamydomonas reinhardtii. These algae evolved multicellularity in response to predation by the ciliate Paramecium; being multicellular provides a degree of protection from the predator, probably because the multicellular colonies are too big for the ciliates to eat. Dr. Chen has identified a handful of genes that may be contributing to the multicellular form through a combination of whole genome sequencing and a genome-wide association experiment.
Dinah Davison showed results quantifying within-strain phenotypic variation in several species of volvocine algae. Species with germ-soma differentiation had less variation in cell number, suggesting that a process of canalization has constrained cell number in differentiated species. Davison, a PhD student in my PhD advisor’s (Rick Michod’s) lab, suggested that this reduced phenotypic variability is related to the higher degree of individuality in differentiated algae, long a theme of Dr. Michod’s research.
There is another session on major transitions Thursday afternoon, so stay tuned.