Peer review isn’t magic

In response to Tom Sheldon’s dire warnings of the dangers of preprints, “Preprints could promote confusion and distortion,” I’ve suggested that what really promotes confusion and distortion is credulous reporters failing to apply basic journalistic standards:

Peer review isn’t a magic wand that guarantees that only solid work gets published, and it isn’t a substitute for skepticism. Reporters have a responsibility to evaluate the evidence in a paper whether it is peer reviewed or not.

A couple of recent examples are relevant. First, the claim by mathematician Michael Atiyah to have proven the Riemann Hypothesis, an immensely important number theory problem related to the distribution of prime numbers. Remember, along with promoting “confusion and distortion,” Sheldon had warned that preprints could rob journalists of “time and breathing space,” pressuring them to rush to sensationalize bad science. Reporting on Atiyah’s claim shows what utter nonsense this is.

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Ulvophyte multicellularity: the sea lettuce genome


Sea lettuce (Ulva sp.), Jericho Beach, Vancouver, BC, February 28, 2011.

David Kirk called the Chlorophyte green algae “master colony-formers” because multicellularity has evolved so many times within this class:

Although members of most chlorophycean genera and species are unicellular flagellates, multicellular forms are present in 9 of the 11 chlorophycean orders (Melkonian 1990). Multicellularity is believed to have arisen independently in each of these orders, and in some orders more than once.

In contrast, multicellularity has probably only evolved once or twice in the probable sister group of the Chlorophyceae, the Ulvophyceae. So when numbers like 25 get thrown around for the number of times multicellularity has evolved, something like half of those times were in the green algae.

We know a lot less about how multicellularity evolved in the Ulvophyceae than we do in the volvocine algae within the Chlorophyceae. A big step forward in understanding ulvophyte multicellularity happened last week, though, with the publication of the Ulva mutabilis genome.

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In defense of preprints

At the end of July, I criticized an opinion piece that Tom Sheldon published in Nature, “Preprints could promote confusion and distortion“:

While the article casts preprints, preprint servers, and scientists who post their work to preprint servers as potential sources of misinformation, its arguments better support the case that science reporters should act more responsibly…What irks me is that I can’t find any hint in the article that Sheldon thinks journalists share the blame when they sensationalize bad science.

The latest issue of Nature includes three more critical responses to Sheldon’s nonsense.

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Volvox inversion review

Alexey Desnitskiy from St. Petersburg State University has published a short review of the process of embryonic inversion in the genus Volvox. It is a translation, by the author, of his Russian-language paper in the journal Ontogenez (Desnitskiy, AG. 2018. Ontogenez 49:147-152). The article, in the Russian Journal of Developmental Biology, isn’t listed as open access, but it also doesn’t seem to be paywalled.

Inversion occurs during the development of all known species in the family Volvocaceae (Colemanosphaera, Eudorina, Pandorina, Platydorina, Pleodorina, Volvox, Volvulina, and Yamagishiella), where it serves to turn the embryo inside-out and get the flagella on the outer surface of the colony. The paper discusses the two distinct inversion processes found in different Volvox species:

…the inversion of “type A” and the inversion of “type B,” represented by the two species most thoroughly studied, respectively V. carteri f. nagariensis and V. globator (Hallmann, 2006; Höhn and Hallmann, 2011). The principal difference between these two types of inversion is that this process begins at the anterior pole of the embryo in the first case, while in its posterior hemisphere in the second case. Coordinated displacements of cells relative to the system of intercellular cytoplasmic bridges play, along with changes of the cell shape, an important role in the inversion process in embryos of both Volvox species. In V. globator, though, the spindle-shaped cells could be observed not in the entire embryo but only in the posterior hemisphere at the stage of its compression.

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