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Pleiotropy
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January 26, 2012
02:38 PM
145 views

Link between political views and physiology

by Bjørn Østman in Pleiotropy

It is becoming more and more clear that political views are in fact not completely decided by rational considerations, as common sense would have us believe. Rather, previous studies have shown a link between emotional (i.e., largely uncontrollable) responses and position on the left/right spectrum: "those on the right are ‘distrustful of differences … fear change, dread disorder, are intolerant of nonconformity, and derogate reason’."*... Read more »

Dodd MD, Balzer A, Jacobs CM, Gruszczynski MW, Smith KB, & Hibbing JR. (2012) The political left rolls with the good and the political right confronts the bad: connecting physiology and cognition to preferences. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 367(1589), 640-9. PMID: 22271780

January 11, 2012
07:08 PM
190 views

What determines rates of ecological speciation?

by Bjørn Østman in Pleiotropy

Speciation models are the most beautiful thing in evolutionary biology. This is widely known, and those who disagree are the crazies. Other models have their place, and empirical evidence for speciation, and insights from there into how speciation takes place are crucial for progress. But real understanding of this question of questions in evolutionary biology only comes once a model is constructed and validated. It is the ultimate goal of scientific work to condense knowledge in terms we can share and peruse, and this we do in models - which you may call theory, but I tend to regard this distinction with distrust.
... Read more »

Birand A, Vose A, & Gavrilets S. (2012) Patterns of species ranges, speciation, and extinction. The American naturalist, 179(1), 1-21. PMID: 22173457

November 22, 2011
10:45 AM
263 views

Reproductive species vs. ecological species

by Bjørn Østman in Pleiotropy

Why are two breeds of dogs who can't mate without human assistance the same species, while two fish species, which can and do have fertile offspring, but which are intermediate in size and therefore not as good at obtaining resources as the parents, are different species?... Read more »

Rice, W., & Hostert, E. (1993) Laboratory Experiments on Speciation: What Have We Learned in 40 Years?. Evolution, 47(6), 1637. DOI: 10.2307/2410209

November 13, 2011
11:50 PM
213 views

Speciation in the virtual social world: Facebook vs. G+

by Bjørn Østman in Pleiotropy

It may just be me and the people I follow, but isn't Google used more for serious stuff that people want others to see, while Facebook is for whatever friends do to each other. That would make sense, I suppose, given that you can't control who follows you on G . But does it mean that G and Facebook are not really competing for the same niche? Even if there are overlapping functions, as there clearly are, are the two so diverged from each other in function that they will continue to coexist side by side in this virtual sympatric habitat of the internet?... Read more »

Nosil P, & Sandoval CP. (2008) Ecological niche dimensionality and the evolutionary diversification of stick insects. PloS one, 3(4). PMID: 18382680

Garant D, Kruuk LE, McCleery RH, & Sheldon BC. (2007) The effects of environmental heterogeneity on multivariate selection on reproductive traits in female great tits. Evolution; international journal of organic evolution, 61(7), 1546-59. PMID: 17598739

Gerhardt HC, & Brooks R. (2009) Experimental analysis of multivariate female choice in gray treefrogs (Hyla versicolor): evidence for directional and stabilizing selection. Evolution; international journal of organic evolution, 63(10), 2504-12. PMID: 19500145

Barrick, J., Yu, D., Yoon, S., Jeong, H., Oh, T., Schneider, D., Lenski, R., & Kim, J. (2009) Genome evolution and adaptation in a long-term experiment with Escherichia coli. Nature, 461(7268), 1243-1247. DOI: 10.1038/nature08480

Østman, B., Hintze, A., & Adami, C. (2011) Impact of epistasis and pleiotropy on evolutionary adaptation. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2011.0870

August 13, 2011
09:46 PM
467 views

Scandinavians have bigger brains for better vision

by Bjørn Østman in Pleiotropy

No matter that this study proposes that people of the north have bigger brains than those at the equator merely to cope with lower levels of sunlight - it would still cause an uproar if the rather large group of people (including scientists) who regularly commit the moralistic fallacy should ever hear about it.We demonstrate a significant positive relationship between absolute latitude and human orbital volume, an index of eyeball size. Owing to tight scaling between visual system components, this will translate into enlarged visual cortices at higher latitudes. Bigger brains, and by usual (though not in this case) inference, higher intelligence ranks at least as high on the list of taboos as race does. Telling someone they are less intelligent is one of the worst things one can say about another. As a consequence, research into intelligence is under more scrutiny than most other disciplines, and freely voicing hypotheticals can get researchers fired.

In the world of bats, saying someone has substandard echolocation is not politically correct. Among snails, calling someone fast is frowned upon. Elephants are known to ostracize those claiming to have longer trunks that others. Because if a bat or snail or elephant is substandard in the prime measure of worth, then the fear is that they will be treated badly by those with better echolocation, speed, and trunks.

But luckily (eh?), the study does not suggest any difference in intelligence after all. Just that we Scandinavians have bigger brains because we need to be more sensitive to light, because there is less of it. Phew! Perhaps now we can even use this data to cancel out any differences in intelligence? After all, that there should be any systematic variation in intelligence among human populations is, unlike many other traits, just unthinkable!!!

</sarcasm></exasperation>

Reference:
Pearce, E., & Dunbar, R. (2011). Latitudinal variation in light levels drives human visual system size Biology Letters DOI: 10.1098/rsbl.2011.0570

... Read more »

Pearce, E., & Dunbar, R. (2011) Latitudinal variation in light levels drives human visual system size. Biology Letters. DOI: 10.1098/rsbl.2011.0570

June 30, 2011
03:29 PM
536 views

Using deleterious mutations to cross fitness valleys - as misunderstood by ID creationists

by Bjørn Østman in Pleiotropy

It is fitting that an article I just got published in Proceedings of the Royal Society B [1] has been blogged about on the ID lover's Uncommon Descent: Are Fitness Valleys Too Deep?
... Read more »

Østman, B., Hintze, A., & Adami, C. (2011) Impact of epistasis and pleiotropy on evolutionary adaptation. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2011.0870

Chou, H., Chiu, H., Delaney, N., Segre, D., & Marx, C. (2011) Diminishing Returns Epistasis Among Beneficial Mutations Decelerates Adaptation. Science, 332(6034), 1190-1192. DOI: 10.1126/science.1203799

Khan, A., Dinh, D., Schneider, D., Lenski, R., & Cooper, T. (2011) Negative Epistasis Between Beneficial Mutations in an Evolving Bacterial Population. Science, 332(6034), 1193-1196. DOI: 10.1126/science.1203801

June 15, 2011
04:37 PM
568 views

Homophobes are turned on by homosexuality

by Bjørn Østman in Pleiotropy

Unfortunately I can't access the full length article of this one: Is homophobia associated with homosexual arousal?But it is obviously too good to miss. The abstract reads:The authors investigated the role of homosexual arousal in exclusively heterosexual men who admitted negative affect toward homosexual individuals. Participants consisted of a group of homophobic men (n = 35 ) and a group of nonhomophobic men (n = 29); they were assigned to groups on the basis of their scores on the Index of Homophobia (W. W. Hudson & W. A. Ricketts, 1980). The men were exposed to sexually explicit erotic stimuli consisting of heterosexual, male homosexual, and lesbian videotapes, and changes in penile circumference were monitored. They also completed an Aggression Questionnaire (A. H. Buss & M. Perry, 1992). Both groups exhibited increases in penile circumference to the heterosexual and female homosexual videos. Only the homophobic men showed an increase in penile erection to male homosexual stimuli. The groups did not differ in aggression. Homophobia is apparently associated with homosexual arousal that the homophobic individual is either unaware of or denies.So, homophobic men are aroused by homosexual porn, and either they don't know it (hmmm), or they deny it (looking at you, Fred Phelps).Reference:Adams, H., Wright, L., & Lohr, B. (1996). Is homophobia associated with homosexual arousal? Journal of Abnormal Psychology, 105 (3), 440-445 DOI: 10.1037/0021-843X.105.3.440... Read more »

Adams, H., Wright, L., & Lohr, B. (1996) Is homophobia associated with homosexual arousal?. Journal of Abnormal Psychology, 105(3), 440-445. DOI: 10.1037/0021-843X.105.3.440

May 13, 2011
01:14 PM
622 views

Keller shows robots evolving altruism - Nowak dismisses simulations

by Bjørn Østman in Pleiotropy

As also reported on Panda's Thumb, Laurent Keller's group have evolved robot behavior in a computer (report in Science). The robots were given the ability to share food with each other, and more related groups quickly evolved altruism, sharing food with other robots they were related to. Classical and unsurprising, at least given our theoretical understanding of the evolution of altruism.However, Martin Nowak, champion of the anti-kin-selection view, in a stunning feat of denial, dismisses the result because they are mere robots.But Harvard University theortician Martin Nowak is more cautious about drawing conclusions based on computer simulations. Virtual robots are not a stand in for real life, he says. "[The work] tells us nothing about whether Hamilton's rule makes a correct prediction for actual biological systems," he says.If you don't think that's ironic, then you don't know much about Nowak's work. Nowak mainly uses mathematics to make inference and draw conclusions about "actual biological systems". In my book, robots that actual do stuff seems much closer to biology than equations.That being said, as I've previously noted, I am personally agnostic about the role of kin-selection in group selection.altruism quickly evolved in the simulation, with greater food-sharing in groups where robots were more related, the researchers report online today in PLoS Biology.Yes, but the fact that individuals groups that are more altruistic are related begs the question of causality. Did altruism evolve because they were related, or did groups of related individuals evolve because they were altruistic? In a situation like the one by Keller's group, these two scenarios may be inseparable. Is there another way to test what comes first, altruism or relatedness? Or rather, can we get altruism in groups of no relatedness?Check out some other cool robots.Waibel, M., Floreano, D., & Keller, L. (2011). A Quantitative Test of Hamilton's Rule for the Evolution of Altruism PLoS Biology, 9 (5) DOI: 10.1371/journal.pbio.1000615... Read more »

Waibel, M., Floreano, D., & Keller, L. (2011) A Quantitative Test of Hamilton's Rule for the Evolution of Altruism. PLoS Biology, 9(5). DOI: 10.1371/journal.pbio.1000615

March 24, 2011
11:59 PM
626 views

The trouble over inclusive fitness theory and eusociality

by Bjørn Østman in Pleiotropy

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 »

Nowak, M., Tarnita, C., & Wilson, E. (2010) The evolution of eusociality. Nature, 466(7310), 1057-1062. DOI: 10.1038/nature09205

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

Nowak, M., Tarnita, C., & Wilson, E. (2011) Nowak et al. reply. Nature, 471(7339). DOI: 10.1038/nature09836

February 9, 2011
05:55 PM
701 views

Loss of anus?

by Bjørn Østman in Pleiotropy

It's nice when we are somewhat certain that evolutionary trees are accurate, so it is unsettling when researchers suggest that they aren't. This time it's Acoels, which are thought to be older than both Protostomes (mouth develops before the anus) and Deuterostomes (anus first). But now a team of evolutionary biologists is suggesting that Acoles belong within the group of Deuterostomes. This even though Acoles don't have a separate mouth and anus at all, but an opening that serves both functions.... Read more »

Philippe, H., Brinkmann, H., Copley, R., Moroz, L., Nakano, H., Poustka, A., Wallberg, A., Peterson, K., & Telford, M. (2011) Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature, 470(7333), 255-258. DOI: 10.1038/nature09676

February 4, 2011
12:18 PM
659 views

Culturomics does not exist

by Bjørn Østman in Pleiotropy

'Culturomics' does not exist. As far as I'm concerned, if it isn't on Wikipedia, it doesn't exist. However, it is listed on Wikipedia's Word of the year for 2010 under the designation 'Least likely to succeed'. As an amusing side note, it also says this: Most Unnecessary: refudiate (Blend of refute and repudiate used by Sarah Palin on Twitter. The laughs.... Read more »

Michel, J., Shen, Y., Aiden, A., Veres, A., Gray, M., , ., Pickett, J., Hoiberg, D., Clancy, D., Norvig, P.... (2010) Quantitative Analysis of Culture Using Millions of Digitized Books. Science, 331(6014), 176-182. DOI: 10.1126/science.1199644

January 30, 2011
05:30 PM
441 views

Selection is random

by Bjørn Østman in Pleiotropy

When is the effect of a mutation neutral?

A mutation (by this I mean any change to the genotype/genome of an organism) is neutral when it does not change the fitness of the organism. This can happen in different ways:

1) A mutation (SNP) that changes one nucleotide in the protein coding sequence, but does not change the amino acid. These are known as synonymous substitutions, and (mostly*) do not affect fitness.
2) When the mutation does not change fitness, just because the genomic change makes no difference for how well the cell/organism functions.
3) ... (See comments?)... Read more »

Watson, R., Weinreich, D., & Wakeley, J. (2011) GENOME STRUCTURE AND THE BENEFIT OF SEX. Evolution, 65(2), 523-536. DOI: 10.1111/j.1558-5646.2010.01144.x

December 29, 2010
05:36 PM
816 views

Pleiotropy is 100 years old

by Bjørn Østman in Pleiotropy

This year, the term pleiotropy was defined 100 years ago, and Frank Stearns, graduate student at the University of Maryland biology graduate program has written a perspective in Genetics, which I highly recommend.... Read more »

Stearns, F. (2010) One Hundred Years of Pleiotropy: A Retrospective. Genetics, 186(3), 767-773. DOI: 10.1534/genetics.110.122549

Wang, Z., Liao, B., & Zhang, J. (2010) From the Cover: Genomic patterns of pleiotropy and the evolution of complexity. Proceedings of the National Academy of Sciences, 107(42), 18034-18039. DOI: 10.1073/pnas.1004666107

December 19, 2010
11:17 PM
537 views

Not possible to absorb alcohol through feet (of course)

by Bjørn Østman in Pleiotropy

Being from Denmark myself, this Danish study caught my eye. It examines what is apparently an urban legend (they call it urban myth, though) in Denmark, namely that one can get drunk by submersing one's feet in alcohol.... Read more »

Hansen, C., Faerch, L., & Kristensen, P. (2010) Testing the validity of the Danish urban myth that alcohol can be absorbed through feet: open labelled self experimental study. BMJ, 341(dec14 2). DOI: 10.1136/bmj.c6812

October 26, 2010
11:21 AM
619 views

Time Tree rocks

by Bjørn Østman in Pleiotropy

I've just learned of a new online application, Time Tree, with which you can search on two species/taxa and get the time since they diverged from each other.... Read more »

Hedges SB, Dudley J, & Kumar S. (2006) TimeTree: a public knowledge-base of divergence times among organisms. Bioinformatics (Oxford, England), 22(23), 2971-2. PMID: 17021158

September 28, 2010
10:09 AM
819 views

Pivar's pure fantasy published

by Bjørn Østman in Pleiotropy

Bogus paper published in serious journal... Read more »

Pivar, S. (2010) The origin of the vertebrate skeleton. International Journal of Astrobiology, 1-21. DOI: 10.1017/S147355041000025X

August 21, 2010
05:39 AM
445 views

Report from Alife XII: life's origin, and its evolution

by Bjørn Østman in Pleiotropy

When I say 'artificial life', what do you think of? I think of life-like systems in computers, mainly, but at the Alife 12 conference in Odense, Denmark that I am currently at, a large part of the presentation are really about chemistry. Many people might be surprise if they knew just how many people are working on the problem of getting chemicals to behave like life. That is, work on the origin of life is booming. ... Read more »

Costanzo, M., Baryshnikova, A., Bellay, J., Kim, Y., Spear, E., Sevier, C., Ding, H., Koh, J., Toufighi, K., Mostafavi, S.... (2010) The Genetic Landscape of a Cell. Science, 327(5964), 425-431. DOI: 10.1126/science.1180823

August 3, 2010
06:36 PM
769 views

The tragedy of the commons

by Bjørn Østman in Pleiotropy

While working on the last bits of my thesis, "Genetic and Ecological Models of Adaptive Evolution", I came upon Garrett Hardin's 1968 article [1], The Tragedy of the Commons (Wikipedia). It's really a great piece, which coined the term that is now an established and important notion in biology and elsewhere.... Read more »

Garrett Hardin. (1968) The Tragedy of the Commons. Science, 162(3859), 1243-1248. DOI: 10.1126/science.162.3859.1243

West, S., Diggle, S., Buckling, A., Gardner, A., & Griffin, A. (2007) The Social Lives of Microbes. Annual Review of Ecology, Evolution, and Systematics, 38(1), 53-77. DOI: 10.1146/annurev.ecolsys.38.091206.095740

July 29, 2010
09:36 PM
863 views

Phytoplankton are disappearing, so we're all going to suffocate

by Bjørn Østman in Pleiotropy

Phytoplankton is responsible for about half of the total amount of oxygen produced by all plant life. That would make a 1% yearly reduction of phytoplankton a really negative outcome of global warming, don't you think?... Read more »

Boyce, D., Lewis, M., & Worm, B. (2010) Global phytoplankton decline over the past century. Nature, 466(7306), 591-596. DOI: 10.1038/nature09268

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