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 schoolpartnership.wustl.edu.

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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Travel grants for Volvox 2019

Volvox 2019 logo

The Fifth International Volvox Conference will be July 26-29, 2019 at the University of Tokyo Hongo campus. For past meetings, generous support from organizations such as the American Genetic Association, the Company of Biologists, Wellcome Trust, and the Phycological Society of America has allowed the organizing committee to award travel fellowships to students and postdocs. It’s not yet clear if that will be the case for next year’s meeting.

Stephanie Höhn has helpfully put together a list of outside travel grants available to students and/or postdocs, along with their deadlines and membership requirements:

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Repost: Message from David Kirk

After last week’s sad news that one of the founding fathers of Volvox research, David Kirk, had passed away, I thought it would be relevant to repost a message he sent a couple of years ago. The modern series of Volvox meetings started in 2011 in Arizona, and we’ve been calling them the First through Fourth International Volvox Conferences, with the Fifth scheduled for July 26-29, 2019. Dr. Kirk wrote in with some interesting historical insight about Volvox meetings that long preceded the current series:

I got an email out of the blue from David Kirk, and I thought some of it would be of interest. Dr. Kirk is one of the biggest names in Volvox research: he carried out much of the developmental genetics that forms the foundation of our field, he literally wrote the book on Volvox evo-devo, and my impression is that most of the PIs currently studying Volvox spent time in his lab as students and postdocs.

VolvoxBookCover

The email was prompted by the meeting review from the 2015 meeting in Cambridge (he liked it, whew! :-D), and he said that he’s looking forward to the 2017 meeting in St. Louis. The email also had a footnote with some interesting information, which I quote here with Dr. Kirk’s permission:

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This awkward condition

I’ve written several times about the process of inversion that occurs during the development of algae in the family Volvocaceae. Today I was going through a paper I’d read (and even written about) before, and I came across a turn of phrase I appreciated regarding inversion:

The fully cleaved embryo contains all of the cells of both types that will be present in an adult but it is inside out with respect to the adult configuration. This awkward condition is quickly corrected by a gastrulation-like inversion process.

The quote is from Benjamin Klein, Daniel Wibberg, and Armin Hallmann’s 2017 paper, “Whole transcriptome RNA-Seq analysis reveals extensive cell type-specific compartmentalization in Volvox carteri.” Setting aside that animal gastrulation and Volvox inversion may not be as similar as they are often portrayed, I love the description of inside-out colonies as “awkward”. As if they just realized they left the house with their shirt half tucked in and inversion is their way of saying “Excuse me while I get myself sorted out here.”

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