Another week, another batch of new papers. [OA] indicates open access. Feel free to request a detailed look at any of these.
Important, General Interest:
Near the end of my post on tracheae, I mentioned that it would be interesting to use terrestrial isopods as models for investigating the convergent evolution of tracheal systems in all terrestrial arthropods. This paper echoes my thoughts exactly, and goes on to review what we know of their evolutionary history from their fossil record, relationships, and biogeography.
One of the more influential geologists of the 20th century, Dieter Meischner died last year. This great eulogy gives a glimpse of what he was like as a person and researcher.
Those who know me would know that such a paper title hits all of my muttons:deep animal phylogeny has always been one of my major research interests, and the uncritical acceptance of molecular phylogenetics is one of my major pet peeves. Luckily, I’m not the only one with such tastes. This paper is one of several by Gert Wörheide examining the various inconsistencies present in current deep metazoan molecular phylogenetics, and how to fix them. I heard a lecture by him where he explained all of this, and his work is pretty exciting. This paper is an excellent showcase of how critical it is to properly sample your genes: every gene has a different history, and all those genetic stories do not match up to the species history – which is what we want to elucidate.
Some cyanobacteria are already commonly grown for biotechnological purposes. Spirulina platensis is used to produce phycocyanins used in health foods and cosmetics, while Lingbya majuscule is used to produce immune modulators for pharmaceuticals. Nostoc commune and Aphanizomenon flos-aquae are also important species. The review goes through the classification of Cyanobacteria – a bit of a muddled mess – and explains their potential for all sorts of biotechnological and environmental applications.
If you’ve ever wondered about how widespread venoms are in the animal kingdom, how this hunting style evolves, and how we use this knowledge for medicine, then you want to read this review.
If you’ve ever wondered how advanced the science of analysing trace fossils (ichnology) is, go through this paper.
- European origin of placodont marine reptiles and the evolution of crushing dentition in Placodontia.
Placodonts were one of the groups of marine reptiles that radiated in the Triassic, before disappearing at the end of the Triassic. They were most notable for having convergently achieved a turtle-like body plan with a bony covering on their underside. Their teeth were large, flat, and heavily-enameled, hinting at an animal that fed by crushing shells (molluscs, brachiopods). The excellent new fossil described in this paper is of a stem placodont, and shows the transition between the ancestral dentition and the specialised placodont shell-crushing teeth.
- Sequencing of the sea lamprey (Petromyzon marinus) genome provides insights into vertebrate evolution. [OA]
I don’t usually care much for these genome-sequencing projects because they don’t tend to target species I consider important – basal ones that hold important clues to decoding phylogenetic history (the giant panda genome may be cool, but it’s useless to all but people who study pandas). This is an example of a good species to sequence: a lamprey, a basal vertebrate, a vestige of the era before vertebrate jaws evolved. Sequencing its genome holds a lot of promise in the quest to flesh out the events that led to the vertebrate radiation that we can’t tell from the fossil record and developmental biology. This paper already dishes out some answers, underlining the importance of innovations in the nervous system.
I can’t say much about the actual results and their implications, I’m just putting this here so you can see just how advanced aDNA research and the associated technology has come. I was very (pleasantly) surprised when I read the title.
Some (me included) say that Chengjiang and other Chinese localities have eclipsed the Burgess Shale by now, but the old quarry still has treasures to yield, as this paper proves. You can find numerous mentions of an undescribed Burgess Shale enteropneust in Simon Conway Morris’s papers (e.g. 1, 2), and I presume this is its long-overdue description.
Another awesome bit of exceptional preservation, also from this week’s Nature, this time from the Chinese Jehol biota: Preservation of ovarian follicles reveals early evolution of avian reproductive behaviour.
Evolutionary medicine, using evolutionary theory to understand the mechanisms behind diseases, is a pretty exciting field, especially in its potential applications to studying cancers (see here, [OA]). This paper argues for investigating cancers with the tools of experimental evolution – putting cancer cells through the rigours of artificial selection to determine how they evolve, adapt, and their ecological limitations, which would then give us insights into how we can curb their proliferation in the body. I support this kind of framework. Read the rest of this entry »
