Volvox newsletter

Volvox newsletter cover

As David Kirk pointed out, what we normally call the First through Fourth International Volvox Meetings are really about the fifth through eighth, as they were preceded by several meetings in the ’70s. The very first meeting was hosted by David and Marilyn Kirk at Washington University in St. Louis. Richard Starr, then at Indiana University, reported on the meeting in the first Volvox Newsletter (Dr. Starr would later move to the University of Texas, and his strains would form the beginning of the UTEX Culture Collection, which is still in operation).

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More Volvox correspondence

I previously corresponded with a science teacher in India, who wrote me with some questions about Volvox. After our initial exchange, my correspondent wrote

Can you please name if there is any unicellular colonial microorganism found?

I asked for clarification and received this reply:

I read about colonial organisms being unicellular and multicellular. Few people think Volvox as colonial organism which is unicellular while Phylum Bryozoa has colonial organisms which are multicellular. The confusion started here. What are colonial microorganisms really? If they are unicellular and multicellular why are they called as colonial then? Bacteria being unicellular which form colonies thought Can bacteria be called as colonial organism? I tried to look for the same but I have not found something solid which says bacteria can be called as colonial organisms. I want to explain colonial organisms to children and don’t want to provide wrong information.

Can you please help in understanding do colonial unicellular microorganism exist? I asked one of the microbiologist I know in here she is also not clear with the concept or probably I might have read something wrong. Need guidance.

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Mary Agard Pocock

Alexey Desnitskiy, Stuart Sym, and Pierre Durand have published a new paper in Transactions of the Royal Society of South Africa recounting the contributions of South African phycologist Mary Agard Pocock to Volvox research [full disclosure: Pierre Durand and I were labmates in Rick Michod’s lab at the University of Arizona for a time, and Alexey Desnitskiy is a friend and collaborator].

Pocock, who defended her Ph.D. in 1932, made careful observations of both sexual and asexual development in several species of Volvox that she collected in southern Africa: V. africanus, V. capensis,V. rousseletii, and V. gigas (which she originally described). For some of these species, hers are still the only detailed descriptions of their ontogeny:

Pocock studied almost all aspects of asexual and sexual development in several African Volvox species, with the exception of sexual differentiation control…Pocock’s data on embryonic inversion in V. africanus, V. capensis, V. gigas and V. rousseletii retain their importance today. Her description of inversion during asexual development in V. africanus and V. capensis remains the only detailed study of this process in these two species and her observations of embryonic inversion in V. gigas and V. rousseletii were corroborated almost 40 years later. [references omitted]

Pocock 1933 Fig. 2L-O

Figure 2L-O from Pocock 1933. Inversion in Volvox gigas.

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I was in Canada

I have been disloyal to the fierce roller. After grad school, I stepped away from Volvox for a couple of years to do a postdoc with Michael Doebeli at the University of British Columbia. I thought I was going to transition to mathematical modeling, and Dr. Doebeli and I did do a bit of that together. I also got my first exposure to next-generation sequencing in his lab. I eventually returned to the fold, but during my time in Canada I wasn’t paying much attention to the Volvox world.

As a result, I missed Jerry Coyne’s coverage of the Volvox genome, which was published in 2010, just as I was discovering Jericho Beach, enjoying cheap sushi, and struggling to understand adaptive dynamics.

What does it take to become multicellular?

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CRISPR/Cas9 mutagenesis in Volvox

Researchers in Stephen Miller’s lab at the University of Maryland, Baltimore County have successfully used CRISPR/Cas9 to knock out several developmentally important genes in Volvox carteri. CRISPR/Cas9 is a relatively new technology that allows heritable mutations to be introduced into living cells at specific locations within the genome.

This advance was announced in a new paper in The Plant Journal by José A. Ortega-Escalante, Robyn Jasper, and Stephen M. Miller (Jasper and Ortega-Escalante are listed as equal contributors). They were able to transform wild-type V. carteri with inversion-deficient and somatic-regenerator mutations, and they transformed somatic regenerator mutants with a gonidialess (no specialized reproductive cells) mutation.

I have never used CRISPR/Cas9, and I don’t know as much about it as I should, so I’m sure any explanation I gave would be riddled with errors. Here’s someone who seems to know what she’s talking about:

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Convergence part 6: the deepest of deep homologies

You are more closely related to a mushroom than a kelp is to a plant. It’s strange to think about, but it’s true. Kelps seem very plant-like, with their root-like holdfasts, stalk-like stipes, and leaf-like blades. But kelps are brown algae, part of the stramenopile (or heterokont) lineage of eukaryotes, which are very distant from the land plants and their green algal relatives, all of which are within the archaeplastida (the direct descendants of the primary origin of chloroplasts). Mushrooms (fungi) and humans (animals), on the other hand, are both opisthokonts, practically cousins at the scale we’re talking about.

Pawlowski 2013 Fig. 1

Figure 1 from Pawlowski 2013. Deep phylogeny of eukaryotes showing the position of small eukaryotic lineages that branch outside the seven supergroups (modified after Burki et al. 2009; drawings S Chraiti). You are represented by a fish, which at this scale you might as well be.

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Volvox email

I got an email from a science teacher in India. This is the internet being what we thought it would be in the 1990s. I did my best to answer, but feel free to weigh in in the comments.

Dear Matthew,

This is Subhashini, I am a science teacher and a content writer for higher secondary school in India. I have gone through your research papers about Volvox. I still have few questions about Volvox. As I do not want children to get confused need some clarification. I would appreciate if you can help me in answering few questions regarding the same.

Q.1 Is Volvox unicellular, multicellular or colonial organism? Why? (I understand the evolutionary process and the relation of the same but need the explanation about specific cellularity.)

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David Kirk obituary from WUStL

David Kirk

David Kirk. Image from

Washington University in St. Louis’s The Source has published an obituary of Dr. David Kirk, who died November 1, by Myra Lopez:

Kirk, who was an active and passionate member of the university community for nearly 50 years, spent a lifetime teaching developmental biology and researching the evolutionary origins of multicellular organisms. He was internationally known for his research on the spherical green alga known as Volvox carteri.

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Convergence part 5: an embarrassment of riches

In parts onetwo, and three of this series, I showed that some intelligent design proponents have created an alternate history of biological thought, in which evolutionary biologists have only recently discovered that similar traits often appear in distantly related species. I showed that this picture is false, and I gave a sampling of quotes–from Jean-Baptiste Lamarck, Charles Darwin, Ernst Mayr, George Gaylord Simpson, Willi Hennig, and others–demonstrating that evolutionary biologists have recognized that this phenomenon is common for as long as there can reasonably be said to have been evolutionary biologists. In part four I explained why widespread convergence is not evidence against common descent, as some ID proponents have claimed.

Mivart Cover

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