An Ode to Unicellularity

Biosphere 2

Biosphere 2, the site of the First International Volvox Meeting in 2011.

This year’s Volvox meeting, as with the previous two, will feature an image/video/arts competition. Erik Hanschen, a graduate student in the Michod lab, has kindly granted me permission to post the winning entry in the poetry contest at the first Volvox meeting: a sonnet in honor of Chlamydomonas.

An Ode to Unicellularity – Erik Hanschen

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Actin evolution in the Volvocales

Fig. 1 from Kato-Minoura et al. 2015

Fig. 1 from Kato-Minoura et al. 2015: Genomic structure of volvocine actin and NAP genes. For comparison, previously identified sequences are also shown. Filled boxes, putative coding exons; open boxes, putative 5′ and 3′ untranslated regions. Intervening sequences are shown by solid lines. Intron positions are indicated by codon and phase numbers with reference to the three alpha-actins of vertebrates (377 amino acids) (Weber and Kabsch 1994). The conserved intron positions are linked with dotted lines. ATG, translation start codon; TAA or TGA, stop codon.

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Evolution is evidence against evolution (?)

Intelligent Design blog Uncommon Descent thinks Betül Kacar’s microbial evolution experiments somehow support their agenda (“E coli hybrid copes with 700 mya engineered gene“). The post quotes extensively from a recent article in Quanta Magazine, which in turn reports on Dr. Kacar’s presentation at AbSciCon (which I briefly covered here).

I’m really not sure what the logic is here. The blog post quotes extensively from the Quanta article (really the post just is quotes from the article, with two short comments added), including sections that make clear that Dr. Kacar observed evolution in action in these experiments:

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New Scientist article on experimental evolution of multicellularity

On the second day of AbSciCon, members of the Ratcliff lab and I met with a reporter, Bob Holmes, from New Scientist. We had all given our talks on the first day of the meeting. The resulting article came out yesterday.

I’ve dealt with New Scientist before, and I find them among the better science news outlets. They make a real effort to understand the science behind their stories, a refreshing change from sites that slap misleading headlines onto barely reworded university press releases. Aaaand I’m going to wrap this up before it turns into a rant.

Peter Conlin, Jennifer Pentz, Bob Holmes, and Will Ratcliff

Peter Conlin, Jennifer Pentz, Bob Holmes, and Will Ratcliff enjoying some sushi in a Chicago park.

Volvox 2015 poster deadline extended

The deadline for poster abstracts for the Third International Volvox Conference has been extended to July 25th (the website says June 25th, but the organizers assure me that it is July). Registration is open until July 15th, so there is still time if you’d like to join us in Cambridge!

The preliminary program is here.

AbSciCon day 4: Mars, life, and Mars life


I stepped out of my comfort zone a bit this morning and went to a session on Mars (okay, there weren’t any biology talks). This is far outside of my expertise, so if I say something outrageously wrong, feel free to set me straight in the comments (actually, you can always do that). I’ve never really given up on the idea of life on Mars. I remember the Viking missions and the ambiguous* results of their biological experiments, and I’m still surprised that none of the subsequent robotic missions have followed them up. I think there are better candidates further out in the Solar System, but Mars is a lot easier to get to.

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AbSciCon day 3: the tape of life

When I was in my 20’s, out of college and largely floundering, my dad lent me a paperback copy of Stephen Jay Gould’s Wonderful Life. I had occasionally enjoyed Gould’s column in Natural History, but I lacked the background to understand much beyond that (my undergrad was in political science). Wonderful Life got me interested in evolution, and I started reading other popular books, including more of Gould’s, Dawkins, Simon Conway Morris (the anti-Gould), etc., and pretty soon I found myself in Chris Parkinson‘s lab working on a master’s degree. This is all just to say that this particular book had a big influence on my life, and my first year in Montana was punctuated (see what I did there?) by a trip to Yoho National Park to see the Burgess Shale, the nominal topic of Wonderful Life.

One of the central arguments of Wonderful Life (and others of Gould’s works) was that the outcome of evolution is inherently unpredictable. Contingency, which can be interpreted as true randomness, stochasticity, or sensitive dependence on initial conditions, plays a large role in Gould’s view. Rarely at a loss for a good metaphor, Gould claimed that if “life’s tape” were rewound to some arbitrary time in the past and played again, the outcome would almost certainly be different from the first run.

This idea of ‘rewinding the tape of life’ has become a mainstay of discussions about evolutionary processes. Many of these discussions revolve around the question of how contingent and how deterministic are evolutionary outcomes, and this was the topic of two AbSciCon sessions chaired by Betul Kacar and Rika Anderson.

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AbSciCon day 2

I didn’t make it to many talks yesterday, spending a good part of the day in meetings, including a meeting of the NASA Postdoctoral Program fellows and alumni. The plenary by Nicholas Hud and Rachel Whitaker was fascinating. I’m not sure it lived up to the very ambitious title, “The origin and subsequent evolution of life,” but it did give some ideas about the transition from prebiotic chemistry to cellular life.

Betul Kacar and Rika Anderson’s session “Chance and necessity: from molecules and viruses to cells and populations I” was the most interesting to me. James Cleaves asked and (partly) answered the question ‘is the set of biological molecules on Earth the best or even the only possible set?’ For RNA at least, there are a huge number of closely related, stable molecules that, by all appearances, should operate just as well as the canonical ribosides that all life on Earth actually uses. If so, it would suggest that the particular molecules that polymerize into RNA are more of a ‘frozen accident’ than anything inevitable.

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AbSciCon day 1

Jennifer Pentz, Dinah Davison, and Cristian Solari enjoying a glass of wine.

Jennifer Pentz, Dinah Davison, and Cristian Solari enjoying a glass of wine.

I’m in Chicago for the biennial Astrobiology Science Conference (AbSciCon). This is always (well, it’s my second time) a fun one, with topics ranging from origins of life to proposed interplanetary missions. I took the train from Whitefish, Montana, which is a bit of an adventure in itself.

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