For some reason, I have been having difficulty getting through to the latest edition, but at last I have succeeded, and it was worth the effort. Behold, it is Tangled Bank #94!
The University of Oregon and Indiana University have this wonderful Integrated Graduate Education and Research Traineeship in evo-devo that was, unfortunately, established long after I graduated from the UO. I have to say that it is a great idea, and it isn’t their fault I’m a superannuated anachronism. Anyway, the important thing is that they are hosting a symposium on evolution, development, and genomics: “From Patterns to Process:
Bridging Micro-and-Macroevolutionary Concepts through Evo-Devo” on
4-6 April, in beautiful Eugene, Oregon. And look at the speakers they have lined up!
Keynote Speakers
Scheduled Speakers
A springtime meeting in Oregon in which I get to hear the latest in evo-devo from some of its biggest names and a rather significant detractor (Coyne)? Well, that settles it for me — I’m going. This sounds like spectacular fun.
Over the past few days I have been running my trials for experiment that was oh so controversial last time I blogged about it. I have been placing two groups of six fish into two solutions containing 0.5% ethanol and 0.25% ethanol. I place them into the solutions for a few hours then compare grouping behaviors. I compare grouping using a computer program to take a picture of the group every minute for 30 minutes. I then use a different computer program to measure the area of the group. The fish spend approximately 10 hrs. in the ethanol solution. After that I put them in a tank with just water, the “sober tank,” overnight and start all over again in the morning.
I am hoping to observe the development of alcoholic tolerance over the course of this experiment. Other studies that I have found doing this sort of thing exposed the fish to alcohol 24/7. I am hoping to observe similar results, but limiting the exposure time to the alcohol. Whether this will happen or not I do not know. When I crunch all of the numbers next week for my report I will find out how this experiment turned out.
Two big specialty science carnivals are up today: Circus of the Spineless #27
and
Encephalon #37. Take your pick, invertebrates or nervous systems…or read them both.
Since Phil has suggestions for holiday telescope shopping, I have to offer some suggestions for microscope shopping. If you really want to get a kid interested in biology, a microscope is a great gift, but I’ll give you the price tag right up front: $150 is probably the minimum to get a decent, low-end student scope.
Last week, I reported on this new breakthrough in stem cell research, in which scientists have discovered how to trigger the stem cell state in adult somatic cells, like skin cells, producing an induced stem cell, a pluripotent cell that can then be lead down the path to any of a multitude of useful tissue types. I tried to get across the message that this is not the end of embryonic stem cell (ESC) research: the work required ESCs to be developed, the technique being used is unsuitable for therapeutic stem cell work, and there’s a long, long road to follow before we actually have stem cell “cures” in hand. A review on LiveScience emphasized similar reservations. Seizing on this one result as an excuse to end research on ESCs would be a great mistake.
So let’s consider what it takes to turn a stem cell into a medically useful tool. One “simple” (we’ll quickly see that it is anything but) example is finding a cure for type 1 diabetes. We understand that problem very well: people with this disease have lost one specific cell type, the β cells of the pancreas, which manufacture insulin. That’s all we have to do: grow up a dish full of just one cell type, the β cells, and plant them back in the patient’s gut, and presto, no more diabetes (setting aside the chronic difficulty of removing whatever destroyed the patient’s original set of β cells, that is). Sounds easy. It’s not.
Paul Davies has written a curious op-ed that has been blithely published by the New York Times. I’m not sure why the NYT saw fit to publish it, except that Davies does have a reputation as a popularizer of physics, and as something of an apologist for deism; they certainly couldn’t have chosen to print it on its merits. His argument is the tired and familiar claim that science has to be taken on faith, so it’s just like religion. I recall hearing variants on this back in the schoolyard, usually punctuated with “nyaa nyaas” and assertions about each others’ mothers, and while we may not have said much about science, the principle was the same. Citing a false equivalency is a cheap argument, but not very credible.
They discriminate against people with sharp pointy spears!
If you’ve been following Lio lately, you know he has a new arthropod friend, rescued from the dinner pot.
Unfortunately, Lio missed the big news.
The fossil record has yielded various gigantic arthropods, in contrast to their diminutive proportions today. The recent discovery of a 46cm long claw (chelicera) of the pterygotid eurypterid (‘sea scorpion’) Jaekelopterus rhenaniae, from the Early Devonian Willwerath Lagerstätte of Germany, reveals that this form attained a body length of approximately 2.5m–almost half a metre longer than previous estimates of the group, and the largest arthropod ever to have evolved. Gigantism in Late Palaeozoic arthropods is generally attributed to elevated atmospheric oxygen levels, but while this may be applicable to Carboniferous terrestrial taxa, gigantism among aquatic taxa is much more widespread and may be attributed to other extrinsic factors, including environmental resources, predation and competition. A phylogenetic analysis of the pterygotid clade reveals that Jaekelopterus is sister-taxon to the genus Acutiramus, and is among the most derived members of the pterygotids, in contrast to earlier suggestions.
This isn’t some casual graspy sort of claw, either—it’s a great spiky wicked looking claw, with pointy daggery bits sticking out that make it look like some medieval weapon of terror.
This is a much more Lio-like creature than the dainty little bug in the cartoon. I wouldn’t mind having one of these for a pet myself! It’s too bad they’ve all been dead for 390 million years.
Braddy SJ, Poschmann M, Tetlie OE (2007) Giant claw reveals the largest ever arthropod. Biology Letters doi:10.1098/rsbl.2007.0491.
A recent discovery in stem cell research is no minor event: researchers have figured out how to reprogram adult cells into a state that is nearly indistinguishable from that of embryonic, pluripotent stem cells. This is huge news that promises to accelerate the pace of research in the field.
The problem has always been that cells exist in distinct states. A skin cell, for instance, has one set of genes essential for its specific function activated, and other sets of genes turned off; an egg cell has different patterns of gene activation and inactivation. Just taking the DNA from a skin cell and inserting it into the egg cell isn’t necessarily going to create a functional egg cell, because genes essential for egg cells may be switched off in the skin cell DNA, and we don’t know how to specifically switch them on. The process of somatic cell nuclear transfer has been hit or miss for that reason, with very high failure rates—scientists are basically trying to make the right configuration of genes switch on by giving the nucleus a good hard kick, and hoping that something in the cells will reconfigure the pattern of gene activation into something appropriate.
What the discovery by Takahashi et al. accomplishes is to reveal how to specifically switch on the right pattern of genes for a pluripotent stem cell. They have discovered the reset button for mammalian cells: a simple trigger that puts the cells in the right state to become anything else.
