When I was in elementary school, I was told that mammals and reptiles could easily be told apart by their teeth. Mammals had a full, enamel-covered toolkit in their mouths—incisors, canines, premolars, and molars suited to different tasks—while reptiles had only one kind of tooth. The dental differences were presented as one of the ways [...]... Read more »
Reichel, M. (2010) The heterodonty of Albertosaurus sarcophagus and Tyrannosaurus rex: biomechanical implications inferred through 3-D models. Canadian Journal of Earth Sciences, 47(9), 1253-1261. DOI: 10.1139/E10-063
SMITH, J. (2005) HETERODONTY IN TYRANNOSAURUS REX: IMPLICATIONS FOR THE TAXONOMIC AND SYSTEMATIC UTILITY OF THEROPOD DENTITIONS. Journal of Vertebrate Paleontology, 25(4), 865-887. DOI: 10.1671/0272-4634(2005)025[0865:HITRIF]2.0.CO;2
Yay, more vesper bats! The groups we've looked at so far have - in anatomical terms - been pretty conservative. This time round we're looking at a really remarkable group; as is so often the case, their familiarity (relative to so many others of the world's bats) means that we tend to forget or ignore how remarkable they are. Ordinarily, you might balk at the idea of a mammal whose ears are longer than the combined length of its head and body. Yet this is exactly what we have in the long-eared bats (or, in the Plecotus species at least). Yes, welcome to the world of... yeah, long-eared bats, or plecotins...
Read the rest of this post... | Read the comments on this post...... Read more »
Bogdanowicz, W., Kasper, S., Owen, R., & Bogdanowicz, W. (1998) Phylogeny of Plecotine Bats: Reevaluation of Morphological and Chromosomal Data. Journal of Mammalogy, 79(1), 78. DOI: 10.2307/1382843
In a favourite example of the behavioural economists, research participants are offered the choice between one bottle of wine a month from now and two bottles of wine one month and one day from now (alternatively, substitute cake, money or some other pay-off for wine). Most people will choose the two bottles of wine. However, [...]... Read more »
Sozou, P. (1998) On hyperbolic discounting and uncertain hazard rates. Proceedings of the Royal Society B: Biological Sciences, 265(1409), 2015-2020. DOI: 10.1098/rspb.1998.0534
BHD syndrome is caused by small nucleotide alterations in the FLCN gene. A total of 132 different mutations have been identified, which are described in the Folliculin Sequence Variation Database. In a large study of 102 BHD syndrome families, only … Continue reading →... Read more »
Benhammou, J., Vocke, C., Santani, A., Schmidt, L., Baba, M., Seyama, K., Wu, X., Korolevich, S., Nathanson, K., Stolle, C.... (2011) Identification of intragenic deletions and duplication in the FLCN gene in Birt-Hogg-Dubé syndrome. Genes, Chromosomes and Cancer. DOI: 10.1002/gcc.20872
Toro, J., Wei, M., Glenn, G., Weinreich, M., Toure, O., Vocke, C., Turner, M., Choyke, P., Merino, M., Pinto, P.... (2008) BHD mutations, clinical and molecular genetic investigations of Birt-Hogg-Dube syndrome: a new series of 50 families and a review of published reports. Journal of Medical Genetics, 45(6), 321-331. DOI: 10.1136/jmg.2007.054304
“5 Seconds!!!” I don’t know about you, but I have always been a big fan of this rule. If you haven’t heard of it, it’s when you drop some food on the floor or ground or somewhere else that is probably pretty gross, and if you pick it up before 5 seconds have passed, it’s [...]... Read more »
Dawson, P., Han, I., Cox, M., Black, C., & Simmons, L. (2006) Residence time and food contact time effects on transfer of Salmonella Typhimurium from tile, wood and carpet: testing the five-second rule. Journal of Applied Microbiology, 2147483647. DOI: 10.1111/j.1365-2672.2006.03171.x
An older study brought to my attention recently (subscription required, though I also found this link).
This is strictly to avoid a dong
being the lead in picture on FoS
The authors want to test some ideas regarding behaviors and adaptations human males may have to ensure paternity. As I heard about this research, my skeptic meter went off and I whipped out my critical thinking tool box to look at this problem and research more closely. The colleague telling me about this research seemed to think I was being a bit of an asshole, but Im used to it.
First, we have to consider the central hypothesis that there is a fitness cost associated with human males not being sure of paternity. Obviously, raising children takes a bazillion resources so from that perspective a dad doesn't want to waste his time and energy raising Chet's kid. That explanation jives with our sense of selves in our current society, but what about 4000 years ago? Prehistorically (and historically for most of the planet) people lived as hunter-gatherers, in family units. Not being an expert in anthropology (maybe Dr. Laden will comment if he sees this post), but my understanding is that a given male in the tribe spends less time raising one specific child. Resources are acquired and distributed amongst the members, fucking socialists. So under most of human evolution, what were the selective pressures that would promote the behaviors the authors take as givens?
Even today, while there are reasons to want to ensure paternity, if paternity were a major part of male behavioral make up, presumably we would all have a dozen mistresses on the side to maximize our chances to get some paternity. Of course, while we were visiting our mistresses, our mates could use that time to help the local studmuffin with his paternity issues.
Basically, I don't like these behavioral rationales because it is trivial to argue them any way you like. We could look at the animal kingdom to gain some potential insights, but that's a clusterfuck as well. Chimpanzees, gorillas, and bonobos all have extremely different sexual behaviors. Lions kill their step children, eagles mate for life, cuckoos force surrogates, seahorse males exclusively care for the young, penguins mate for a season raise a chick then trade up or at least out. So whatever human behavior you want to rationalize, there will be an example in the animal kingdom you can use.
Modified from paper
Ok, so let's take the behavioral rationales off the table and simply look at what the authors did. One thing they wanted to test was the semen displacement hypothesis. What? You don't know what the semen displacement hypothesis is? Well, its the idea that the shape of the penis allows it to act like a scoop to remove another dudes semen if said other dude recently had sex with the woman you were currently copulating with.
The authors acquired some artificial penises (commonly known as dildos) and an artificial vagina (commonly referred to as damned if I know) and made artificial semen (cornstarch and water). The authors put the "semen" in the "vagina" and then "copulated" using the "penis". (If ever a sentence needed scare-quotes.) Then the amount of "semen" remaining was then measured to come up with the following data set.
These are the phallus types
So both dildo penis B and D, which have scoops displaced 85-90% of the cornstarch. Whereas VibroMaxxx penis C displaced 30-40% of the cornstarch. It looks like the hypothesis is supported. However, I have some concerns. First, cornstarch isnt semen. For one thing, semen contains spermatozoa that swim, like towards an egg cell. The authors removed that variable by making the "vagina" a closed orifice. By sealing one end, there's no place for anything else to go but stay still or be pulled out. In the real world, maybe the act of secondary copulation pushes more semen and sperm of the first guy deeper into the vagina closer to the cervix and the ultimate prize the egg. That was not an option here.
Second, where have all the good sperm gone? During ejaculation, the sperm come out with a fair bit of thrust (yes, I know). While much of the semen remains within the vaginal cavity, I wonder how quickly sperm that most likely fertilize an egg leave the vagina? The vaginal cavity is not a hospitab... Read more »
On one side we have the majority of evolutionary biologists who think kin selection and inclusive fitness theory as described by Hamilton and Price explain a lot of phenomena in biology, notably eusociality. Some of the more famous people squarely in this group are Jerry Coyne, Richard Dawkins, and Stuart West, but there are many more (at least 137*).... Read more »
Abbot, P., Abe, J., Alcock, J., Alizon, S., Alpedrinha, J., Andersson, M., Andre, J., van Baalen, M., Balloux, F., Balshine, S.... (2011) Inclusive fitness theory and eusociality. Nature, 471(7339). DOI: 10.1038/nature09831
A "science brief today" featuring a very brief overview of the new in vitro sperm cell line.... Read more »
Sato T, Katagiri K, Gohbara A, Inoue K, Ogonuki N, Ogura A, Kubota Y, & Ogawa T. (2011) In vitro production of functional sperm in cultured neonatal mouse testes. Nature, 471(7339), 504-7. PMID: 21430778
A 45 year old female teacher had a history of severe obsessive-compulsive disorder, along with other problems including ADHD. Her daughter, and many other people in her family, had suffered the same problems and in a few cases had Tourette's Syndrome.But all that changed - when she suffered a stroke. This is according to a brief case report from Drs. Diamond and Ondo of Texas:[she] had a long history of constant intrusive and obsessive thoughts that interrupted her daily activities and sleep. She had constant unfounded fears that something bad would happen to her family and had persistent violent thoughts of using knives to harm family members. She would check the door locks up to 15 times a day. In addition to her OCD symptoms, she had ... inattention, poor concentration, and difficulty sitting still.She had never been treated for the OCD, despite how it interfered with her life, because she feared losing her job as a teacher if she sought psychiatric help. But then... Nine months before approaching us, she developed the acute onset of paresthesia [weird sensations] and weakness in the left upper extremity and face, associated with slurred speech. Initially, she was unable to lift her arm against gravity. These are classic signs of a stroke, but it was a very mild one, because the symptoms only lasted a few minutes and were pretty much gone even before she arrived at the emergency room. She made a full recovery. More than a full recovery in fact:Within weeks of her stroke, she realized that her obsessive and intrusive thoughts, fears, rituals, and impulsive behavior had completely resolved. In addition, there was some improvement in her temperament. There was no improvement in attention or concentration. Owing to her improvement in neuropsychiatric symptoms, she strongly felt that her stroke was beneficial. These benefits have persisted for 24 months.Most medical case reports concern patients who died, or got really sick, in a particularly interesting fashion, but this one has a happy ending. Strokes can be devastating, of course, although people also make full recoveries - it all depends on the severity of the stroke, and whether they get prompt treatment.There have been a few other cases of brain damage which brought unexpectedly beneficial effects. In Vietnam veterans, for example, people with damage to the vmPFC due to combat trauma seemed to be protected from depression.Whether the stroke really cured her, or whether it was some kind of psychological "placebo" effect, we'll never know. It's hard to see why a stroke would have a placebo effect, but on the other hand, an MRI scan revealed that the stroke occured in an area of the brain - the right frontoparietal cortex - which is fairly low down on the list of "OCD-ish" areas.The authors make some vague comments about "modulation of the cortical–subcortical circuits" but this is really the neuroscientific equivalent of saying "We guess it did something", because the entire brain is made of cortical-subcortical circuits, given that the cortex is at the top and everything else is, by definition, the sub-cortex. It's quite possible. But we really can't tell.Diamond A, & Ondo WG (2011). Resolution of Severe Obsessive-Compulsive Disorder After a Small Unilateral Nondominant Frontoparietal Infarct. The International journal of neuroscience PMID: 21426244... Read more »
Diamond A, & Ondo WG. (2011) Resolution of Severe Obsessive-Compulsive Disorder After a Small Unilateral Nondominant Frontoparietal Infarct. The International journal of neuroscience. PMID: 21426244
Imagine if your comfortable existence was suddenly and traumatically disrupted by a disaster. Your home is destroyed, food becomes scarce, and social structures suddenly break down. Even the most civilized people would respond to this situation with desperation, doing whatever it takes to survive in the short-term without the usual considerations for the long term.
Now [...]... Read more »
Wu L, Estrada O, Zaborina O, Bains M, Shen L, Kohler JE, Patel N, Musch MW, Chang EB, Fu YX.... (2005) Recognition of host immune activation by Pseudomonas aeruginosa. Science (New York, N.Y.), 309(5735), 774-7. PMID: 16051797
Zaborin A, Romanowski K, Gerdes S, Holbrook C, Lepine F, Long J, Poroyko V, Diggle SP, Wilke A, Righetti K.... (2009) Red death in Caenorhabditis elegans caused by Pseudomonas aeruginosa PAO1. Proceedings of the National Academy of Sciences of the United States of America, 106(15), 6327-32. PMID: 19369215
Seal JB, Morowitz M, Zaborina O, An G, & Alverdy JC. (2010) The molecular Koch's postulates and surgical infection: a view forward. Surgery, 147(6), 757-65. PMID: 20494210
Giant bunnies are not scary. MGM learned that the hard way with the 1972 schlock film Night of the Lepus. No amount of fake blood or artificial saliva could turn those rabbits into real monsters, and the brief moments when actors in bunny suits attacked their co-stars looked like some kind of “Meet the Easter [...]... Read more »
Quintanaa, J.; Köhler, M.; Moyà-Solà, S. (2011) Nuralagus rex, gen. et sp. nov., an endemic insular giant rabbit from the Neogene of Minorca (Balearic Islands, Spain). Journal of Vertebrate Paleontology, 31(2), 231-240. info:/10.1080/02724634.2011.550367
So, have you spend all day looking for a comic that integrates Red Queen evolutionary dynamics, commentary on the application of parsimony arguments in biology, and Newt Gingrich's recent flip-flopping on Libya? No? Well, hopefully you'll enjoy this anyway. For a more viewable image, see the original at Darwin Eats Cake.
URL for hotlinking or embedding: http://www.darwineatscake.com/img/comic/11.jpg
For more on the flip-flop check out Think Progress or Weigel.
Van Valen, L (1973). A New Evolutionary Law Evolutionary Theory, 1, 1-30
... Read more »
Van Valen, L. (1973) A New Evolutionary Law. Evolutionary Theory, 1-30. info:/
A study published yesterday in the Journal of Clinical Investigation reports the whole-genome sequencing of a mouse acute promyelocytic leukemia (APL) genome. This is a subtype of AML, characterized by the presence of a t(15;17) translocation that creates the PML-RARA fusion oncoprotein. In mice, you can induce expression of PML-RARA transgenically, and they’ll develop APL [...]... Read more »
Wartman, L., Larson, D., Xiang, Z., Ding, L., Chen, K., Lin, L., Cahan, P., Klco, J., Welch, J., Li, C.... (2011) Sequencing a mouse acute promyelocytic leukemia genome reveals genetic events relevant for disease progression. Journal of Clinical Investigation. DOI: 10.1172/JCI45284
Rampal, R., & Levine, R. (2011) Finding a needle in a haystack: whole genome sequencing and mutation discovery in murine models. Journal of Clinical Investigation. DOI: 10.1172/JCI57200
Recently, I watched The King's Speech , the Academy Award-winning biopic starri...... Read more »
Ross, E. (1984) Right hemisphere's role in language, affective behavior, and emotion. Trends in Neurosciences, 342-346. DOI: 10.1016/S0166-2236(84)80085-5
Bryngelson, B., & Clark, T. (1933) Left-handedness and stuttering. Journal of Heredity, 387-390. info:/
Humanity’s great scourges had a rough century after their victims finally armed themselves with germ theory, vaccines, and antibiotics. Smallpox was suppressed into extinction. Tuberculosis is tamed. The plague is no longer a death sentence. Cancer remains, but we are making strides against it and starting to figure out new ways to fight it. But [...]... Read more »
Metzger, V., Lloyd-Smith, J., & Weinberger, L. (2011) Autonomous Targeting of Infectious Superspreaders Using Engineered Transmissible Therapies. PLoS Computational Biology, 7(3). DOI: 10.1371/journal.pcbi.1002015
There is a provocative article in this week’s New England Journal of Medicine asking whether the accelerated approval process should be used for more cancer drugs: “The striking results of recent phase 1 trials of targeted cancer drugs have provoked … Continue reading →
... Read more »
Chabner, B. (2011) Early Accelerated Approval for Highly Targeted Cancer Drugs. New England Journal of Medicine, 364(12), 1087-1089. DOI: 10.1056/NEJMp1100548
Cancer cells have taught biologists about a lot of wacky things that can happen when things don’t go merrily along for a cell. Entosis is a process in which a living cell is internalized into a neighboring cell, and has been found to occur in some tumors. A recent paper describes exactly what can go wrong here.Aneuploidy refers to a cell having an incorrect number of chromosomes, and is a feature of many cancers. Typically, aneuploidy occurs from a failure in cytokinesis, the physical division of a cell after mitosis, due to misregulation or mutation of genes involved in cell division. Sometimes, however, aneuploidy can occur from a non-genetic failure of cytokinesis, according to a recent paper. In this paper, Krajcovic and colleagues look at cytokinesis failures due to entosis, a process in which living cells are internalized by their neighboring cells. These cell-in-cell structures are found in some tumors, and the outer “host” cell is frequently aneuploid. This aneuploidy occurs when the internalized cell physically disrupts the constriction required to cleave two cells during cytokinesis, as seen in the images above. Cytokinesis of the cell-in-cell structure (left) is not going well compared with a normal cell (right). Red labels (and in black and white insets) mark active constriction during cytokinesis, and should be symmetric around the cells. The mitotic spindle is labeled in green, and chromosomes in blue. BONUS!! Movie of above cell, attempting cytokinesis, can be found here. More cool movies from this paper can be found here.Krajcovic, M., Johnson, N., Sun, Q., Normand, G., Hoover, N., Yao, E., Richardson, A., King, R., Cibas, E., Schnitt, S., Brugge, J., & Overholtzer, M. (2011). A non-genetic route to aneuploidy in human cancers Nature Cell Biology, 13 (3), 324-330 DOI: 10.1038/ncb2174Adapted by permission from Macmillan Publishers Ltd, copyright 2011... Read more »
Krajcovic, M., Johnson, N., Sun, Q., Normand, G., Hoover, N., Yao, E., Richardson, A., King, R., Cibas, E., Schnitt, S.... (2011) A non-genetic route to aneuploidy in human cancers. Nature Cell Biology, 13(3), 324-330. DOI: 10.1038/ncb2174
Another dispatch from the outer reaches of GISland. Yesterday’s post on the likely consequences of climate change around my mother-in-law’s farm in Kenya got me thinking that it would be nice to see where that locality fits in the global vulnerability scene. One can actually do that thanks to a recent paper in Global Ecology [...]... Read more »
Samson, J., Berteaux, D., McGill, B., & Humphries, M. (2011) Geographic disparities and moral hazards in the predicted impacts of climate change on human populations. Global Ecology and Biogeography. DOI: 10.1111/j.1466-8238.2010.00632.x
It's one of the most persistent problems in camouflage: how do you hide your eyes?
Skin is not that difficult to disguise. You can change its color, cover it up, match it to your environment. But eyes are tricky. You have to be able to see out of them. And unfortunately, predators are extremely good at looking for eyeballs.
I'm not a predator, but I am a marine biologist, which is kind of the same thing. I've done my time searching through plankton soup for squid larvae--and I can tell you the best way to search is to look for the eyes. They're just so recognizable!
read more... Read more »
Holt AL, Sweeney AM, Johnsen S, & Morse DE. (2011) A highly distributed Bragg stack with unique geometry provides effective camouflage for Loliginid squid eyes. Journal of the Royal Society, Interface / the Royal Society. PMID: 21325315
It is time I introduce a bit the research I am doing for my PhD, here at the Pompeu Fabra-CSIC university The main area of our research is to study whether there is correlation between the position of a gene … Continue reading →
Related posts:a discussion about node centralities with G.Scardoni Last week we hosted the visit of G.Scardoni, the author...
scripting Cytoscape to plot different Node Centrality measures Finally I have made it: scripting and automatizing Cytoscape with...
a resume on the Workshop on Evolutionary Systems Biology, Edinburgh 2010 This is a resume of the workshop on Evolutionary Systems...
Related posts brought to you by Yet Another Related Posts Plugin.... Read more »
Montanucci L, Laayouni H, Dall'Olio GM, & Bertranpetit J. (2011) Molecular evolution and network-level analysis of the N-glycosylation metabolic pathway across primates. Molecular biology and evolution, 28(1), 813-23. PMID: 20924085
Do you write about peer-reviewed research in your blog? Use ResearchBlogging.org to make it easy for your readers — and others from around the world — to find your serious posts about academic research.
If you don't have a blog, you can still use our site to learn about fascinating developments in cutting-edge research from around the world.
Research Blogging is powered by SMG Technology.
To learn more, visit seedmediagroup.com.