Thursday, April 25, 2013

Lab-meeting on multiple adaptive peaks and predator-mediated natural selection




Posted by Erik Svensson

On Tuesday (April 30, 10.30) I was thinking that we should discuss a short paper that was recently published in Science, showing an empirical example and application of the Adaptive Landscape concept. I choose this paper to demonstrate that the idéa of the adaptive landscape is not just a theoretical construct, but could actually stimulate empirical and experimental studies. This was also the main rationale for the publication of our book on the topic last year, which is cited in the current paper. You will find the Abstract below, and the paper can be reached here. 

As another example of how "landscape thinking" and fitness surfaces can guide empirical work, I will also send around a manucript draft about predator-mediated natural selection in Calopteryx-demoiselles, that stems from the field work former postdoc Shawn Kuchta did in our lab between 2007 and 2009. We would both love to get some input on this manuscript, short or long, either during the lab-meeting or before or after (if you cannot attend). I will send you an e-mail with this paper attached well before the lab-meeting, but if you do not receive it and wish to have a copy, please do not hesitate to send me an e-mail (erik.svensson@biol.lu.se).

Any fika-volunteer?


Science
Vol. 339 no. 6116 pp. 208-211 
DOI: 10.1126/science.1227710
  • REPORT

Multiple Fitness Peaks on the Adaptive Landscape Drive Adaptive Radiation in the Wild

The relationship between phenotype and fitness can be visualized as a rugged landscape. Multiple fitness peaks on this landscape are predicted to drive early bursts of niche diversification during adaptive radiation. We measured the adaptive landscape in a nascent adaptive radiation ofCyprinodon pupfishes endemic to San Salvador Island, Bahamas, and found multiple coexisting high-fitness regions driven by increased competition at high densities, supporting the early burst model. Hybrids resembling the generalist phenotype were isolated on a local fitness peak separated by a valley from a higher-fitness region corresponding to trophic specialization. This complex landscape could explain both the rarity of specialists across many similar environments due to stabilizing selection on generalists and the rapid morphological diversification rate of specialists due to their higher fitness.

Sunday, April 21, 2013

"The Adaptive Landscape is dead - long live the Adaptive Landscape!" Review of our OUP-volume in TREE

Posted by Erik Svensson

In a forthcoming review in Trends in Ecology & Evolution, Andrew MacColl (University of Nottingham, UK), has an entertaining, albeit short, review of our edited volume "The Adaptive Landscape in Evolutionary Biology"

The review is quite favorable, but will not be quoted in its entire length, but can be read here.  But I still want to cite one of the most entertaining part:

"A history of vicious power struggles in mediaeval Europe led to a desperate need to avoid interregna on the death of a monarch and, hence, the instantaneous proclamation of an heir's succession. The adaptive landscape, a king among metaphors, has been declared dead many times. Yet its dynasty continues; the power of its simple evocation supplantable only by a parliament of similar ideas that risks becoming all things to all people. A surprising aspect of The Adaptive Landscape in Evolutionary Biology (no criticism this, it could hardly have been otherwise) is that it cannot, even after the 80 years of academic endeavour that it celebrates, deliver a unified verdict on so apparently simple a concept. Instead, it does an excellent job of showcasing the radiation of ideas that has diverged from Wright's original [1]."

P.S.: You can order your copy here and if you are interested in reading the volume in a group of graduate students, postdocs or faculty members, there is an excellent study plan here. 

Friday, April 19, 2013

Lab Meeting Tuesday April 23: Human personality and genetics

In keeping with the human theme from this week, I suggest we read Verweij et al.'s recent Evolution paper on the genetics of human personality for lab meeting next week. The title/abstract and link to the article can be found below. In their article, they have chosen to use Cloninger's 4 dimensions of temperament as their personality measure.

Here is a wikipedia article with a bit of background about this measure of personality: http://en.wikipedia.org/wiki/C._Robert_Cloninger, including some of the controversies surrounding these particular indices. Temperament is determined via a 240-question questionnaire, as described here: http://en.wikipedia.org/wiki/Temperament_and_Character_Inventory.

And for those of you interested in finding out your own temperament dimensions, you can take the Temperament and Character Inventory for free at this website: http://www.anthropediafoundation.org/site/PageServer?pagename=wwd_TCI. It would be interesting to discuss some of our own results, for anyone who has the time to take it!

In addition to the article discussion, Anna Norden will start the lab meeting by giving us a presentation of her Master's work on assortative mating in Calopteryx (demoiselle) damselflies.

I will provide fika! See you there...


MAINTENANCE OF GENETIC VARIATION IN HUMAN PERSONALITY: TESTING EVOLUTIONARY MODELS BY ESTIMATING HERITABILITY DUE TO COMMON CAUSAL VARIANTS AND INVESTIGATING THE EFFECT OF DISTANT INBREEDING


  1. Karin J.H. Verweij1,2,3
  2. Jian Yang1
  3. Jari Lahti4
  4. Juha Veijola5
  5. Mirka Hintsanen6,
  6. Laura Pulkki-Råback6
  7. Kati Heinonen4,
  8. Anneli Pouta7
  9. Anu-Katriina Pesonen4,
  10. Elisabeth Widen8
  11. Anja Taanila9
  12. Matti Isohanni4
  13. Jouko Miettunen5
  14. Aarno Palotie8,10,11
  15. Lars Penke12
  16. Susan K. Service13
  17. Andrew C. Heath14
  18. Grant W. Montgomery1
  19. Olli Raitakari15
  20. Mika Kähönen16
  21. Jorma Viikari17
  22. Katri Räikkönen4
  23. Johan G Eriksson7,18,19,20,21
  24. Liisa Keltikangas-Järvinen6
  25. Terho Lehtimäki22
  26. Nicholas G. Martin1
  27. Marjo-Riitta Järvelin9,23,24,25
  28. Peter M. Visscher1,
  29. Matthew C. Keller26,27
  30. Brendan P. Zietsch1,2,3,28
Personality traits are basic dimensions of behavioral variation, and twin, family, and adoption studies show that around 30% of the between-individual variation is due to genetic variation. There is rapidly growing interest in understanding the evolutionary basis of this genetic variation. Several evolutionary mechanisms could explain how genetic variation is maintained in traits, and each of these makes predictions in terms of the relative contribution of rare and common genetic variants to personality variation, the magnitude of nonadditive genetic influences, and whether personality is affected by inbreeding. Using genome-wide single nucleotide polymorphism (SNP) data from > 8000 individuals, we estimated that little variation in the Cloninger personality dimensions (7.2% on average) is due to the combined effect of common, additive genetic variants across the genome, suggesting that most heritable variation in personality is due to rare variant effects and/or a combination of dominance and epistasis. Furthermore, higher levels of inbreeding were associated with less socially desirable personality trait levels in three of the four personality dimensions. These findings are consistent with genetic variation in personality traits having been maintained by mutation–selection balance.

Thursday, April 11, 2013

Praise for our book "The Adaptive Landscape in Evolutionary Biology"

As you hopefully remember, last year Ryan Calsbeek at Dartmouth College and I published an edited volume entitled "The Adaptive Landscape in Evolutionary Biology" (Oxford University Press 2012). Although we have generally gotten positive feedback and responses when talking research colleagues at meetings, relatively few reviews have yet appeared, probably because it is a relatively recent publication. Here is one very flattering review, however, published on the blog "Nothing in biology makes sense".

I thank the blog author for his kind words, and have to cite some of the nice formulations on a very long and thorough review:

"Unlike a recent book addressing aspects of the modern synthesis, Evolution: The Extendend Synthesis (Pigliucci and Müller, 2010) which called for a revolution, Svensson and Calsbeek have assembled authors that explore the innovations and contributions that build upon the fundamental ideas of population genetics and seek to grow the field. Early in this book, Pigliucci asks about the utility of the Adaptive Landscape metaphors, even titling his chapter with the question, “what are they good for?” I think the rest of the book provides a more than sufficient answer to his question."

and:

"Over the course of this semester, my colleagues and I read and discussed each of the chapters. Our group consisted of a diversity of backgrounds spanning evolution, ecology, and behavior. We included a range of experience from first and second year graduate students to postdocs as well as junior and senior faculty. While we read the book in the sequential order it was published in, each part could certainly be pulled out and read as a separately. Some of the chapters make cross references to each other but not enough that reading them independently would be impossible. While some chapters certainly provided more challenges to some, this forced our discussion to flesh out explanations that the text just didn’t have time to go into. I think that the first two parts might make particularly good set of readings to supplement an upper level Evolution or Population Genetics course."

and:

"My recommendationThis is a book ideally suited for a graduate level seminar in any Biology department. While it may be good to read a few chapters on your own, the book benefits from an active discussion of the content. We took 14 weeks to go through the entire book, reading one chapter most weeks occasionally two (or three). This pace allowed everyone to casually complete the readings. Going slowly through the book also allowed us to digest the material and make connections among the chapters without getting too overwhelmed with new information each week. You can follow this link to see the schedule we followed. If you are not convinced about the utility of this book yet, below I highlight some of the excellent contributions contained within the different parts."

and finally:

"CONCLUSION: I would strongly encourage students of population genetics to pick up this excellent volume and spend some contemplative weeks reading through the chapters. Better yet, grab a group of your department colleagues and argue about the 80 years of interpretation of the Adaptive Landscape. I personally cannot wait to see where this excellent metaphor leads us."


Wednesday, April 10, 2013

Lack of Support for the Association between Facial Shape and Agression: no more violence, no more reproductive success

Posted by Jessica Abbott on behalf of Anais Rivas Torres

The Dr. Spurzheim phrenology chart


For the next lab meeting, we will discuss the following paper:


The study provides new scientific evidence to reject the hypothesis that facial features are associated with antisocial and criminal behaviour, an idea that had much influence in the mid-nineteenth century and has recently returned in force. To conduct the research, the authors used a sample of 4960 individuals from 94 populations around the world.  This has allowed them to have an overview of facial shape and be able to make a much more accurate analysis, taking into consideration the variation in different forms.

As the basis of the study protocol, the authors have studied the index fWHR - that is, the relationship between facial width and facial height - as a possible predictor of aggressive behavior in populations of men.

The meeting will be at the usual place and time.  Jessica will bring fika.

Monday, April 8, 2013

New lab member for EXEB: Alice Evans

Alice Evans  started last week as a new Masters student at the lab and will be working on the genetics of the colour polymorphism of the blue tailed damselfly Ischnura elegans under the supervision of Maren Wellenreuther and Elin Videvall.

Below you can find a photo of the study species and Alice, and a description by Alice of her project.

 

Research Interests

I am broadly interested in all topics of molecular ecology, but particularly in conservation genetics, evolution and population genetics. I am currently undertaking a project on the genetics of colour polymorphism, using the damselfly Ischnura elegans as a model organism. I hope to isolate the gene region associated with colour polymorphism, and analyse the statistical differences between the three allele pools of different colour morphs, to improve our understanding of this phenomena in a mostly genetically unstudied organism.

Publication

Graeme R. Gillespie, Eddie Ahmad, Berjaya Elahan, Alice Evans, Marc Ancrenaz,
Benoit Goossens, Michael P. Scroggie. Conservation of amphibians in Borneo: Relative value of secondary tropical forest and non-forest habitats. 2012. Biological Conservation.

Friday, April 5, 2013

Updated information about lab-meeting on April 9: ERC, phylogenies and tropical diversification

This is an update about the coming lab-meeting on Tuesday April (10.30), as there was some mis-communication, and it turns out Lesley will not be able to attend the meeting due to a course in landscape genetics, and this is probably also the case for Rachel and Maren. The lab-meeting on Tuesday will start with  Jessica presenting her ERC-talk for the coming interview in Brussels, and she can then get final feedback from the lab-members that attend. Our new student Anais from Cataluna has also promised to bring some catalunian "fika", and we can try out the red wine she brought last week.

Then, we should discuss this paper that I originally suggested which deals with how the use of multiple phylogenies can be used to answer basic ecological and evolutionary questions about the niche conservatism and range expansions and test the classical "tropical conservatism" hypothesis. This paper is in press in Evolution, and is quite long, but in case you have time you can also read the shorter paper Lesley suggested that was published in Ecology Letters

Both these papers are thematically similar and demonstrate the power of a phylogenetic perspective and modern comparative methods to address fundamental problems and general processes in ecology and evolution. The titles and abstracts of both papers are posted below. Enjoy!

WHAT CAN MULTIPLE PHYLOGENIES SAY ABOUT THE LATITUDINAL DIVERSITY GRADIENT? A NEW LOOK AT THE TROPICAL CONSERVATISM, OUT OF THE TROPICS, AND DIVERSIFICATION RATE HYPOTHESES



We reviewed published phylogenies and selected 111 phylogenetic studies representing mammals, birds, insects, and flowering plants. We then mapped the latitudinal range of all taxa to test the relative importance of the tropical conservatism, out of the tropics, and diversification rate hypotheses in generating latitudinal diversity gradients. Most clades originated in the tropics, with diversity peaking in the zone of origin. Transitions of lineages between latitudinal zones occurred at 16–22% of the tree nodes. The most common type of transition was range expansions of tropical lineages to encompass also temperate latitudes. Thus, adaptation to new climatic conditions may not represent a major obstacle for many clades. These results contradict predictions of the tropical conservatism hypothesis (i.e., few clades colonizing extratropical latitudes), but support the out-of-the-tropics model (i.e., tropical originations and subsequent latitudinal range expansions). Our results suggest no difference in diversification between tropical and temperate sister lineages; thus, diversity of tropical clades was not explained by higher diversification rates in this zone. Moreover, lineages with latitudinal stasis diversified more compared to sister lineages entering a new latitudinal zone. This preserved preexisting diversity differences between latitudinal zones and can be considered a new mechanism for why diversity tends to peak in the zone of origin.




  • Alex L. Pigot*
  • Joseph A. Tobias



  • Whether biotic interactions limit geographic ranges has long been controversial, and traditional analyses of static distribution patterns have made little progress towards resolving this debate. Here, we use a novel phylogenetic approach to test whether biotic interactions constrain the transition to secondary sympatry following speciation. Applying this temporal framework to a diverse clade of passerine birds (Furnariidae), we reject models of geographic range overlap limited purely by dispersal or environmental constraints, and instead show that rates of secondary sympatry are positively associated with both the phylogenetic and morphological distance between species. Thus, transition rates to sympatry increase with time since divergence and accelerate as the ecological differences between species accumulate. Taken together, these results provide strong empirical evidence that biotic interactions – and primarily ecological competition – limit species distributions across large spatial and temporal scales. They also offer phylogenetic and trait-based metrics by which these interactions can be incorporated into ecological forecasting models.