New thesis from the lab by Kristina Karlsson, nailing and next lab-meeting

Probably, the proudest moment in the life of PhD-student advisors is when their students has finished his/her thesis. This has now happened once again in our lab, and I am of course extremely happy that my fourth PhD-student Kristina Karlsson has now gotten her PhD-thesis back from the printer. Before Tina, Jessica Abbott (2006), Tom Gosden (2008) and Fabrice Eroukhmanoff (2009) has previously succesfully finished their theses, and I am of course happy to soon be able to kall Tina Dr. Karlsson.

The second proudest moment in the life of the PhD-student advisors is usually the thesis defence. This will take place on Friday November 26 2010 in the "Blue Hall" (Ecology Building). The external opponent on Tinas thesis will be Professor Nina Wedell (Exeter University, UK), and the thesis defence will start at 09.30.

Prof. Wedell will also give an invited research seminar the day before Tinas thesis dissertation (November 25) with the title: "Sexual selection and selfish genetic elements". This talk will take place in the "Red Room" (Ecology Building) at 14.00 on November 25 2010. Needless to say, both Prof. Wedell's talk on November 25 as well as the dissertation ceremony on November 26 are open to the general public and everybody who is interested.

Tina will "nail" her thesis on the "Oak" outside the Biology Library next Wednesday (November 10, 2010) at 15.00. Drinks will be served after this ceremony, and again, it is open to anyone who wish to attend. The same day, our regular lab-meeting will take place as usual (10.15-12.00 in "Darwin"). Anna Runemark will send out a manuscript of ours about sexual selection in mainland and island populations, with the hope to get some input and criticisms. If you do not receive this manuscript, please send Anna an e-mail and she can send you a copy (anna.runemark@zooekol.lu.se). Fika volunteers are particularly welcome to this meeting.

Lab-meeting about intralocus sexual conflict and seminar by Jessica Abbott

This week's lab-meeting has been moved to Thursday morning (10.00-12.00) and to the seminar room "Fagus" (third floor above "Darwin"), due to the seminar by outside visitor and former lab-member Jessica Abbott in the same day, in the afternoon (14.00, "Blue Hall").

The theme of Jessica's talk will be intralocus sexual conflict and genetic constraints, and that will also be the theme of our lab-meeting. I was thinking that we should discuss a recent review by Jessica in Proc. R. Soc. Lond. B. about how one can study intralocus sexual conflict in hermaphroditic animals. Hopefully, Jessica will arrive in time to comment on this paper as well, her expected arrival time to the Department is about 11.00.

Before we discuss Jessica's interesting review-paper, we will discuss a manuscript that I and Fabrice Eroukhmanoff have written about population variation in intersexual genetic correlations and sexual dimorphism in aquatic isopods (Asellus aquaticus). We have worked on this manuscript for quite a while and we would be interested in getting some input. The results have clear links to the research topic and interests by Jessica. We will send you out this manuscript in a separate e-mail, hopefully today (Monday). Send me an e-mail if you do not get it (erik.svensson@zooekol.lu.se).

After our lab-meeting in "Fagus", there will be opportunity to go for lunch with Jessica, and at 14.00 her seminar starts in the "Blue Hall" in the Ecology Building, entitled:


"Using sex-limited evolution to detect evolutionary constraints"

You can read more about Jessica's research here, and here you can find a list of past and more recent publications. 

New PhD-thesis in the lab: Fabrice Eroukhmanoff

I am pleased to announce that a new PhD-thesis will now be defended in our group: Fabrice Eroukhmanoff's Magnum Opus "The interplay Between Selection and Constraints on adaptive Divergence and Phenotypic Evolution".

This is the third Ph.D.-student that has finished his/her thesis in our lab, the previous two were Jessica Abbott (2006) and Tom Gosden (2008). You can find an abstract and more informaton about the thesis here. Well done Fabrice!

The thesis will be defended on Friday November 20 in the Blue Hall (Ecology Building). The external opponent will be Professor Andrew Hendry from McGill University Canada, and the thesis committé will consist of Professors Anna Qvarnström (Uppsala University), Karin Rengefors (Limnology, Lund University) and Janne S. Kotiaho (University of Jyväskylä, Finland). The thesis defence is open to everyone, and I encourage you to participate in this exciting event.

Lab-meeting on population divergence in isopods and lizards

This coming Wednesday (30 September), we will discuss one manuscript by Fabrice, Anders Hargeby and me on sexual isolation and migration modification in the aquatic isopod (Asellus aquaticus) and another one by Anna, Bengt and me on colour polymorphism divergence and population genetics in Podarcis-lizards. We would like to have the input from as many as possible on these two interesting manuscripts (at least we think they are interesting, but as authors we are of course highly biased!).

We will start with the lizard manuscript at 10.00, and continue with the isopod manuscript after that. I will send out these manuscripts by e-mail to the whole group today (Monday) provided that Anna and Fabrice send me the updated last versions first. If you do not get it by e-mail, please e-mail Anna (anna.runemark@zooekol.lu.se) and Fabrice (fabrice.eroukhmanoff@zooekol.lu.se) so that they can send you the manuscripts.

Time and place as usual: "Darwin" at 10.00 on September 30 (Wednesday). Any fika volunteer?

Lab-meeting on G-matrix divergence i isopods

This coming Wednesday (16 September), we will discuss genetic correlations and G-matrices in aquatic isopods (Asellus aquaticus). It is a manuscript that Fabrice and I have worked on for quite a while now, and which is one of the papers in his Ph.D.-thesis that he will defend on November 20. Naturally, we would appreciate all constructive input and criticisms so that we can incorporate these before Fabrice will handle in his thesis to the printer on October 20.

This manuscript which deals with morphological variation and quantiative genetics of morphology, should also be of interest to Tina and Sanna, who have been working recently on phenotypic and genetic correlations of behavioural traits in these isopods.

You can get this manuscript by e-mailing me (erik.svensson@zooekol.lu.se) or Fabrice (fabrice.eroukhmanoff@zooekol.lu.se). If Fabrice sends me the last version, I will also send out this manuscript to the group tomorrow (Monday).

Time and place as usual: "Darwin-room" at 10.00 on Wednesday 16 September. Any fika volunteer?

Adaptation driven by novel mutations or from selection on standing genetic variation?

Our collegue Hopi Hoekstra at Harvard University in the US, who visited us in August last year, has a paper in one of the last issues of Science. You can read a brief report on the website Science Daily here.

At first I was not very excited about this paper, as it appears to be the usual story about the melanocortin receptor (MC1R) and how it affects coat colour patterns in various mice populations, a story that by know is sufficiently wellknown and established so one wonders what remains to be discovered.

MC1R is responsible for dark coat colour in mice that occur in dark habitats (see above), e. g. on the dark lava flows in Arizona, that Hopi Hoekstra has previously studied together with her colleague Michael Nachmann.

However, this new paper has a new twist: it appears as if selection has acted on a novel mutant in deer mice in Nebraska, and this novel that apparently appeared in the population shortly after the last Ice Age, about 8 000 years ago.

Catherine Linnen and Hopi have analyzed genetic variation among these different mice populations and estimated the age of the allele that causes light coat colour in the mice. Light coloured mice carry a certain allele at a gene called Agouti, and this allele is quite young as it shows evidence of a selective sweep through reduction in DNA sequence diversity around that particular allele. Linnen and Hoekstra have thus used the well-known statistical approach of coalescense analysis to infer the age of the novel mutation at the Agouti locus that is causing light coat colour.

This result is important, as it provides some contrast to recent suggestions that novel mutations might not be that important in cases of rapid evolutionary change, which have instead emphasize selection on standing genetic variation in rapid evolutionary change. For instance, rapid evolutionary change need not always to rely on standing genetic variation as suggested by the findings from other systems like sticklebacks. The alternative is instead that rapid adaptive change is driven by a process by which selection in novel environments "picks up" and favours alleles that already segregated in the ancestral population, rather than "waiting" for the emergence of rare novel beneficial mutations (that might take long time to appear).

This process is sometimes also called phenotype sorting, referring to how a polymorphic and variable base populations might become transformed in to a new (monomorphic and less variable) population through the selective increase and selective loss of already existing phenotypes, which are then "filtered" by selection in the novel environment. Something along these lines appears to also be the case in the freshwater isopods that we have studied in our group, and we discussed this earlier this year in a paper published in Journal of Evolutionary Biology, which you can find here.

In summary, the relative importance of selection acting on novel mutations vs. standing genetic variation is probably something that will be discussed a lot the coming years in evolutionary biology and ecology.

On isopod antipredator adaptations in PLoS ONE

This week, Fabrice Eroukhmanoff and I have a paper about antipredator adaptations and phenotypic integration in the famous aquatic isopod (Asells aquaticus), the main study organism in Fabrice's Ph.D.-thesis work. The paper is published in the popular and fast growing "Open Acess"-journal PLoS ONE, which despite some initial skepticism, has rapidly emerged as a major scientific publisher.

I would encourage you to read this paper and if you have time and have registered as a user at PLoS, feell free to comment upon it. This is one of the major strength of publishing in PLoS-journals: the interactivity between readers and published articles.

Here is the abstract for those who are interested:

Fabrice Eroukhmanoff, Erik I. Svensson

Abstract

"It is increasingly being recognized that predation can be a strong diversifying agent promoting ecological divergence. Adaptations against different predatory regimes can emerge over short periods of time and include many different traits. We studied antipredator adaptations in two ecotypes of an isopod (Asellus aquaticus) that have, diverged in parallel in two Swedish lakes over the last two decades. We quantified differences in escape speed, morphology and behavior for isopods from different ecotypes present in these lakes. Isopods from the source habitat (reed) coexist with mainly invertebrate predators. They are more stream-profiled and have higher escape speeds than isopods in the newly colonized stonewort habitat, which has higher density of fish predators. Stonewort isopods also show more cautious behaviors and had higher levels of phenotypic integration between coloration and morphological traits than the reed isopods. Colonization of a novel habitat with a different predation regime has thus strengthened the correlations between pigmentation and morphology and weakened escape performance. The strong signature of parallelism for these phenotypic traits indicates that divergence is likely to be adaptive and is likely to have been driven by differences in predatory regimes. Furthermore, our results indicate that physical performance, behavior and morphology can change rapidly and in concert as new habitats are colonized."