Bacterial flagellum? Never heard of it.

When I wrote about Michael Behe’s shock that any sane person would associate the bacterial flagellum with intelligent design (Michael Behe’s “Secret Obsessions“), I failed to notice something that was staring me right in the face. The masthead for intelligent design blog Uncommon Descent:

UncommonDescentMasthead

Remember, if you meet someone who thinks intelligent design advocates

…think they [bacterial flagella] are examples of “intelligent design”

or that bacterial flagella have

…been at the center of the thinly veiled creationism movement called intelligent design,

you should

back away slowly, smiling, wishing him a nice day…

Volvox by Aeravi

Volvox by Aeravi. Oil on canvas.

Volvox by Aeravi. Acrylic on canvas.

A painting of my favorite critter by my favorite artist. Here’s what she has to say about it:

I am convinced of a connection between arts education and scientific discovery. Also, I love science. Also, science gives artists endless material to play with AND understanding of how things like light work, giving us more tools to play with. Here are some of my paintings inspired by Volvox, a very beautiful algae that lives in freshwater… like Flathead Lake and the Ninepipes Resevoir.

There is lots more good stuff over at her blog…check it out!

Michael Behe’s “secret obsessions”

In his latest post at Evolution News and Views, Michael Behe calls the authors of posts at New Scientist and Genetic Engineering & Biotechnology News ‘crazy’ and ‘clueless’ for associating arguments about the bacterial flagellum with intelligent design (“New Paper on Flagellum Reveals Secret Obsessions“):

Suppose in the course of a pleasant conversation with a colleague you mentioned your vacation last year in Las Vegas. All of a sudden he starts ranting about Area 51 — Vegas is only a few hours away, right? Did you see any lights in the sky? Any military vehicles heading north? You should stay at the Little A’Le’Inn motel like he has six times. You’ll see some funny stuff there.

You’d probably back away slowly, smiling, wishing him a nice day…

[much later] …One crazy person is a coincidence. Two are a trend…What’s more, if you go by what they write, these folks are utterly clueless about what modern ID proponents actually argue. [my emphasis]

The evidence that these authors are crazy and clueless? The New Scientist‘s assertion that the bacterial flagellum is

Loved by creationists, who falsely think they are examples of “intelligent design”

and that of Genetic Engineering & Biotechnology News that

[T]he bacterial flagellum has been at the center of the thinly veiled creationism movement called intelligent design. Subscribers to this belief system have erroneously postulated that the flagellar motor system is “irreducibly complex” and could not have come about through Darwinian evolutionary mechanisms….It is doubtful these findings will sway the opinion of its detractors, yet they do make it extremely more difficult for them to make their case.

Seriously, that is the sum total of the evidence that these authors are ‘crazy’ and ‘clueless’ on the order of UFO true believers. A bit hyperbolic, I think. But where did these clueless authors get their crazy idea to associate the bacterial flagellum with intelligent design?

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Origins of the sexes: Takashi Hamaji on mating type determination

The evolution of sex is one of the big outstanding problems in evolutionary biology. The origin of sex is one of Maynard Smith and Szathmáry’s “Major Transitions,” on which I’m currently teaching a course here at the University of Montana. Our discussion of sex luckily coincided with the visit of the grad-invited Distinguished Speaker, Sally Otto, an important theorist on this topic (among others). Dr. Otto generously agreed to join us for the discussion, which turned out to be one of the best we’ve had.

A related problem to the origin of sex is the origin of males and females. Sexual reproduction doesn’t always involve males and females: lots of species that don’t even have males and females have sex. There are lots of traits that we associate with males and females — fancy plumage, differences in body size and type of genitalia, presence and absence of exaggerated weapons — but what actually defines males and females is differences in gamete size. Animals, plants, and other organisms with males and females are oogamous: males have small, swimming sperm, and females have large, immotile eggs. But lots of single-celled eukaryotes have only one size of gamete. We call these isogamous (‘equal gametes’).

Some volvocine algae are isogamous (such as Chlamydomonas), some are oogamous (such as Volvox), and some (such as Pleodorina) are anisogamous (‘unequal gametes’), meaning that the gametes come in two sizes but both can swim. In spite of not having sexes per seChlamydomonas, like a lot of isogamous organisms, comes in two ‘mating types’, which are arbitrarily called ‘plus’ and ‘minus.’ The mating types are self-incompatible, in other words plus can only mate with minus and vice versa.

All this variation in mating systems makes the volvocine algae a great model system for understanding the evolution of sex and the sexes (see ‘Volvox 2015: all about sex‘). We know from previous work that males evolved from the minus mating type and females from the plus in this lineage. But males and females have evolved from isogamous ancestors many times, and to my knowledge we don’t know which came from which for any other group.

Takashi Hamaji and colleagues have just published an analysis of the genomic region that determines mating type in Gonium pectorale, an isogamous alga more closely related to Volvox than to Chlamydomonas.

Figure 1 from Hamaji et al 2016. A schematic diagram for phylogenetic relationships of selected volvocine species based on Nozaki et al. (2000); Herron and Michod (2008). The top row illustrates gamete type and structure. Tubular mating structures in isogamous gametes are indicated with red bars at the flagellar base. The possession of a MID gene is shown next to the minus mating type or male gametes. The lower row of cartoons depicts vegetative morphology (not to scale) for the indicated species.

Figure 1 from Hamaji et al 2016. A schematic diagram for phylogenetic relationships of selected volvocine species based on Nozaki et al. (2000); Herron and Michod (2008). The top row illustrates gamete type and structure. Tubular mating structures in isogamous gametes are indicated with red bars at the flagellar base. The possession of a MID gene is shown next to the minus mating type or male gametes. The lower row of cartoons depicts vegetative morphology (not to scale) for the indicated species.

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Message from David Kirk

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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Fierce Roller is moving!

cropped-Volvox-tertius2.jpg

I got word Sunday night that my application to join the blogging community at Freethought Blogs was approved, so starting today Fierce Roller will be located at https://freethoughtblogs.com/fierceroller/. I’m trying to figure out how to migrate previous posts to the new platform; meanwhile, this site isn’t going anywhere (it just won’t be updated).

Hello world!

Hi, everyone! I’m excited (and surprised, to be honest) to join the freethoughtblogs community. I’ve been blogging for about ten months over at fierceroller.com, a platform that I initially set up to serve the (pretty small) Volvox community. Volvox, in case you haven’t encountered it before, is a multicellular green alga, just visible to the naked eye, that is an important model system for understanding the evolution of multicellularity. Volvox is Latin for ‘fierce roller,’ a name bestowed by Linnaeus, who was impressed by their ability to move around without limbs.
Volvox aureus. Beautiful, isn't it?

Volvox aureus. Beautiful, isn’t it?

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Controlling contamination in Chlamydomonas cultures

Figure 1 from Wang et al. 2016.  Effects of bactericide/fungicide cocktails on the removal of microbial contaminants from Chlamydomonas reinhardtii cultures.

Figure 1 from Wang et al. 2016. Effects of bactericide/fungicide cocktails on the removal of microbial contaminants from Chlamydomonas reinhardtii cultures. (A) Control plate. (B) Plate with the One-shot Solution cocktail composed of ampicillin, cefotaxime, and carbendazim. (C) Plate with axoxystrobin and nalidixic acid. (D) Plate with tebuconazole and nalidixic acid. 1: uncontaminated cultures; 2–4: contaminated cultures containing fungi and bacteria.

A new paper in BioTechniques describes an improved antibiotic cocktail for controlling bacterial and fungal contamination of Chlamydomonas cultures. This is a problem that has cost our lab many hours, especially when using media that include acetate.

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