Bjørn Østman

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  • December 26, 2008
  • 01:00 AM

Neanderthals outcompeted by humans?

by Bjørn Østman in Pleiotropy

Wouldn't you love it if the Neanderthals hadn't gone extinct, but were still living with us today? I'd give my right arm to see that (but then again, I'd give my right arm to be ambidextrous). It is still hotly debated how they went extinct, but a paper in PLoS ONE [1] concludes that Homo neanderthalensis were outcompeted by humans.... Read more »

William E. Banks, Francesco d'Errico, A. Townsend Peterson, Masa Kageyama, Adriana Sima, & Maria-Fernanda Sánchez-Goñi. (2008) Neanderthal Extinction by Competitive Exclusion. PLoS ONE, 3(12). DOI: 10.1371/journal.pone.0003972  

R GREEN, A MALASPINAS, J KRAUSE, A BRIGGS, P JOHNSON, C UHLER, M MEYER, J GOOD, T MARICIC, & U STENZEL. (2008) A Complete Neandertal Mitochondrial Genome Sequence Determined by High-Throughput Sequencing. Cell, 134(3), 416-426. DOI: 10.1016/j.cell.2008.06.021  

  • December 8, 2008
  • 01:00 AM

Graham's cancer selection is without merit

by Bjørn Østman in Pleiotropy

Via a Google advertisement entitled "Evo-Devo" needs "Onco" I found my way to the website of a James Graham. He wrote a book that he published himself in 1993: Cancer Selection: The New Theory of Evolution.Warning: verbose!On his website he writes of himself in the third person:He postulates that cancer killed uncountable numbers of immature animals and concludes that the resulting accumulation of defenses against the disease enabled the emergence of complexity. In all evolving animal lineages ........ Read more »

  • December 6, 2008
  • 01:00 AM

Efficiency is not what matters most in evolution

by Bjørn Østman in Pleiotropy

A stealthy gait is favored in cat locomotion.... Read more »

Kristin L. Bishop, Anita K. Pai, & Daniel Schmitt. (2008) Whole Body Mechanics of Stealthy Walking in Cats. PLoS ONE, 3(11). DOI: 10.1371/journal.pone.0003808  

  • December 1, 2008
  • 01:00 AM

Success in life is predetermined

by Bjørn Østman in Pleiotropy

If, at age four, you are good at resisting temptation, then you will do better in life than those that aren't.... Read more »

Inge-Marie Eigsti, Vivian Zayas, Walter Mischel, Yuichi Shoda, Ozlem Ayduk, Mamta B. Dadlani, Matthew C. Davidson, J. Lawrence Aber, & B.J. Casey. (2006) Predicting Cognitive Control From Preschool to Late Adolescence and Young Adulthood. Psychological Science, 17(6), 478-484. DOI: 10.1111/j.1467-9280.2006.01732.x  

  • November 30, 2008
  • 01:00 AM

Watching multicellularity evolve before our eyes

by Bjørn Østman in Pleiotropy

Chlorella vulgaris is an asexual, unicellular green alga. It has been observed in the laboratory to maintain unicellularity for thousands of generations. Boraas and his collaborators (1998) kept Chlorella for two decades in this way. Then they decided to add a predator, Ochromonas vallescia, also a unicellular organism. It has a flagellum (a tail with which it can swim about), and it eats Chlorella. This is bad news for the Chlorella population, which thus experiences a shift in selective pressu........ Read more »

  • November 9, 2008
  • 01:00 AM

Head injury as a cause of ADHD

by Bjørn Østman in Pleiotropy

Head injury is not a causative factor of ADHD, but it may be a marker for subsequent diagnosis of ADHD.... Read more »

  • November 5, 2008
  • 01:00 AM

Homosexuality is catholic in the animal kingdom

by Bjørn Østman in Pleiotropy

Beetles, bisons, black swans, bonobos, dolphins, elephants, flamingos, fruit bats, fruit flies, giraffes, lions, lizards, macaques, orangutans, ostriches, penguins, sheep. What do these animals have in common?They are all homosexual. In fact, the list is much, much longer. Here is what Petter Bøckman has to say about it:No species has been found in which homosexual behaviour has not been shown to exist, with the exception of species that never have sex at allWe can thus safely conclude that the........ Read more »

  • October 28, 2008
  • 01:00 AM

Development shapes evolution in silico

by Bjørn Østman in Pleiotropy

Why are there so few extant phyla or basic body-plans? There are only about 35 phyla, and nine of them include 96% of all living species. There used to be many more, back in the early days of the cambrian explosion, so one has to wonder why so many phyla were singled out for extinction, and just a few have gone on to do very well.The usual way to learn about our evolutionary history is to look at fossils. Unfortunately, fossils don't tell us very much about how the organisms developed, and this ........ Read more »

  • October 10, 2008
  • 01:00 AM

Non-functional DNA conserved in evolution

by Bjørn Østman in Pleiotropy

When a stretch of DNA is really important for an organism, natural selection will make sure that it is not changed much from generation to generation. This is termed purifying selection, and whenever it is observed, the conserved DNA is responsible for some function that the organism can't do without.Conversely, when a stretch of DNA is observed to code for an important function in the organism, it is a pretty solid guess that it is highly conserved by purifying selection. Survival and/or reprod........ Read more »

McLean, Bejerano. (2008) Dispensability of mammalian DNA. Genome Research.

  • October 7, 2008
  • 01:00 AM

Evolution and pleiotropy

by Bjørn Østman in Pleiotropy

Pleiotropy is the effect of one gene affecting multiple traits, as when Drosophila genes are expressed in more than one place during embryogenesis. For a bunch of examples of that, seeRepression and loss of gene expression outpaces activation and gain in recently duplicated fly genes, Oakley, Østman, and Wilson, 2006, PNAS, 103, 11637.In my own work on computer simulations of epistatic interactions, it is clear that pleiotropy has the effect of changing the phenotype more per mutation than with........ Read more »

  • October 6, 2008
  • 01:00 AM

Natural Selection Fails to Optimize Mutation Rates

by Bjørn Østman in Pleiotropy

Rich Lenski's group published this paper in PLoS Computational Biology less than two weeks ago:Clune J, Misevic D, Ofria C, Lenski RE, Elena SF, Sanjuán, R. (2008). Natural Selection Fails to Optimize Mutation Rates for Long-Term Adaptation on Rugged Fitness Landscapes. PLoS Comput Biol 4(9). PLoS Computational Biology, 4 (9).In the Ph.D. program I'm in we are required to give a journal club talk once per semester (the result of which is that that's exactly how many we give), and I chose to do ........ Read more »

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