Lab-meeting on gene expression and sexual conflict + WIP-genetics

Posted by Erik Svensson

Next week's lab-meeting will take place in the afternoon, due to some conflicting activites, and we will be in "Darwin", rather than the usual "Argumentet". We will discuss the paper about gene expression differences and sexual conflict in Nature Communications that we did not have time to digest last week, and this will be followed by a short summary by Jessica about our work in progress regarding the molecular genetic basis of Wing Interference Patterns (WIPs) in Drosophila melanogaster.

When: Tuesday, April 8, 13.30 (NOTE: Changed time!)
Where: "Darwin", 2nd floor, Ecology Building

"Entomology Futures" - Minisymposium on insect ecology and evolution

  Posted by Erik Svensson

Next week EXEB will co-organize a Minisymposium together with The Pheromone Group at the Biology Department in Lund entitled "Entomology Futures", which will focus on insect ecology and evolution.

This symposium is organized in conjunction with the visit by Dr. Niklas Wahlberg from University of Turkku in Finland to our department. Wahlberg is a leading phylogeneticist and systematist who mainly works on butterflies, but has broad ranging research interests in evolutionary biology and entomology.

The symposium is open for everyone interested, although the locality is small and can only take 20-25 attendants, meaning that you should aim to arrive early.

When: Wednesday March 5 2014, 14.00-16.00
Where: Seminar room "Tanken", 1st floor, Ecology Building

Scientific Program

14.00 - 14.30 Niklas Wahlberg: The 215 million years of Lepidoptera diversification: lessons from an ever changing world

14.30 - 15.00 Jadranka Rota: Behavioural ecology and systematics of metalmark moths (Lepidoptera: Choreutidae)

15.00 - 15.20 Coffee break

15.20 - 15.40 Machteld Verzijden: Courtship and mate preference functions are jointly shaped by geographic variation in developmental plasticity and interspecific interactions

15.40 - 16.00 Jessica Abbott: G x E effects of diet on male fitness in Drosophila melanogaster: phenotypic plasticity, or genetic robustness?

Does sexual and natural selection operate against each other or in the same direction?

Posted by Erik Svensson

During last week's lab-meeting we talked a little about the relationship between natural and sexual selection, and to what extent these processes are opposed to each other vs. operate in the same direction and favours the same phenotypic trait values. Next week we will continue discussing this theme based on a recent article about sexual and natural selection in fruitflies (Drosophila melanogaster) in Current Biology. This article by Long, Agrawal and Rowe does also have some important implications for what kind of inferences that can be made to natural populations based on studies in laboratory settings, with a cautionary tale.

Time and place as usual: "Argumentet "(2nd floor, Ecology Building) at 10.30, Tuesday, February 5.

Below, you will find Abstract and link to the article.

The Effect of Sexual Selection on Offspring Fitness Depends on the Nature of Genetic Variation

• Tristan A.F. Long^1, 2, , , 
• Aneil F. Agrawal¹, 
• Locke Rowe¹

• ¹ Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
• ² Department of Biology, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada

• http://dx.doi.org.ludwig.lub.lu.se/10.1016/j.cub.2011.12.020, How to Cite or Link Using DOI

• Permissions & Reprints

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Summary

Whether the changes brought about by sexual selection are, on the whole, congruent or incongruent with the changes favored by natural selection is a fundamentally important question in evolutionary biology. Although a number of theoretical models have assumed that sexual selection reinforces natural selection [1 and 2], others assume these forces are in opposition [3, 4 and 5]. Empirical results have been mixed (see reviews in [1, 6, 7 and 8]) and the reasons for the differences among studies are unclear. Variable outcomes are expected if populations differ in their evolutionary histories and therefore harbor different amounts and types of segregating genetic variation. Here, we constructed populations of Drosophila melanogaster that differed in this regard to directly test this hypothesis. In well-adapted populations, sexually successful males sired unfit daughters, indicating sexual and natural selection are in conflict. However, in populations containing an influx of maladaptive alleles, attractive males sired offspring of high fitness, suggesting that sexual selection reinforces natural selection. Taken together, these results emphasize the importance of evolutionary history on the outcome of sexual selection. Consequently, studies based on laboratory populations, cultured for prolonged periods under homogeneous conditions, may provide a skewed perspective on the relationship between sexual and natural selection.

Lab-meeting about developmental biology and our ongoing Drosophila-research

This coming Tuesday (November 6 2012), we will listen to an informal research presentation by our Japanese postdoc Natsu, who will tell us about her research progress on the genetics and function of Wing Interference Patterns (WIP:s) in Drosophila melanogaster. This is a collaborative project, involving Natsu, Jessica, Jostein Kjaerandsen and myself. Above, you see three of us and Yuma working in the laboratory, trying to get matings between males from inbred lines that differ in their WIP:s and wild-type females. Below that, you see some of the test vials where mate choice is taking place, in this case against black background, which is though to increase perception of the signal (WIP:s).

Time and place for lab-meeting as usual: "Argumentet" at 10.30 (Wednesday, November 6). Natsu will also tell us a little about her PhD-work on plant developmental biology, that took place in Japan, before she came to Lund for her postdoc to work on Drosophila. It should be very interesting, I hope. I also hope that Natsu can bring some unusual "fika", hopefully with Japanese touch :).

Most welcome!

Happy Easter!

Posted by Erik Svensson

I wish all of you, readers and lab-members alike and whereever you are, a Happy Easter. For those of you who are spending part of the holidays in finishing your VR-applications, I hope you can take a few hours break from work.

As for next week, lab-meeting will take place on Wednesday April 11 at 13.30 in "Argumentet". Postdoc Miriam Henze from the "Vision Group" in the Biology Department will tell us a little bit about her ongoing work, progress and recent research results on sensory physiology of the fascinating model organism: the damselfly Ischnura elegans, and how males perceive the three different female colour morphs in this species.

After this, Jessica Abbott wants to have some input on a manuscript she is working on which is about epigenetic inheritance (or the lack thereof) in the charismatic fruitfly Drosophila melanogaster. Jessica will send out a copy of her manuscript later, so that we all can read it well before the meeting and give valuable input to Jessica. 

Lab-meeting on intralocus sexual conflict and transcriptomics

It is time for the fall's first lab-meeting, and what could possibly be a better start than to discuss a paper about how intralocus sexual conflict might (or might not!) leave a transcriptomic signature in the organism? The study I wish to discuss is a relatively new paper in PLoS Biology by Paulo Innocenti and Ted Morrow. The authors combined quantitative-genetic fitness assays in the fruitfly (Drosophila melanogaster) to investigate sex-biased gene expression and its links to intralocus sexual conflict, i. e. the developmental conflict that arises between male and female phenotypes, that arises due to the fact that both sexes share a common gene pool.

We have discussed intralocus sexual conflict and its consequences in previous lab-meetings, and some of our recent lab-publications that are relevant to this topic can be found here (lizards) and here (damselflies). The authors of the current study used microarrays to study sex-specific transcripts, a technique which is now rapidly replaced by "454-sequencing" and other methods in this rapidly moving field of molecular biology.

The time and place for the lab-meeting is as usual: Wednesday August 15 at 10.15 in the "Darwin Room" (2nd floor, Ecology Building). Fika volunteers are encouraged to step forward. Below, I have put an abstract to the paper which can be downloaded here, and you can also find an interesting short comment by Robin Meadows, also published in PLoS Biology.

Abstract 

When selective pressures differ between males and females, the genes experiencing these conflicting evolutionary forces are said to be sexually antagonistic. Although the phenotypic effect of these genes has been documented in both wild and laboratory populations, their identity, number, and location remains unknown. Here, by combining data on sex-specific fitness and genome-wide transcript abundance in a quantitative genetic framework, we identified a group of candidate genes experiencing sexually antagonistic selection in the adult, which correspond to 8% of Drosophila melanogaster genes. As predicted, the X chromosome is enriched for these genes, but surprisingly they represent only a small proportion of the total number of sex-biased transcripts, indicating that the latter is a poor predictor of sexual antagonism. Furthermore, the majority of genes whose expression profiles showed a significant relationship with either male or female adult fitness are also sexually antagonistic. These results provide a first insight into the genetic basis of intralocus sexual conflict and indicate that genetic variation for fitness is dominated and maintained by sexual antagonism, potentially neutralizing any indirect genetic benefits of sexual selection.

Author's summary

Males and females of many species are different: many of these differences are thought to have evolved because the sexes often have needs and strategies that do not coincide. For example, in fruit-flies, females may do best by concentrating their efforts in acquiring resources to be able to lay more eggs, while males would benefit most from increasing their mating and fertilization success. Such differences generate a sexual “conflict of interests”, and since as a general rule each behavioural, morphological or physiological characteristic is regulated by the same set of genes in the two sexes, this conflict takes place ultimately at the genetic level. In our study, we combined data on the reproductive success of different lines of fruit-flies with their gene expression profiles. We show that a large proportion of genes that contribute to male fertilization success are detrimental for female fecundity, and vice-versa. These results indicate that an optimal genotype for both sexes does not exist: many genes maintain different variants because they have opposite effects in males and females, perhaps helping to explain how genetic diversity is maintained in the face of selection.

Citation: Innocenti P, Morrow EH (2010) The Sexually Antagonistic Genes of Drosophila melanogaster. PLoS Biol 8(3): e1000335. doi:10.1371/journal.pbio.1000335

Lab-meeting about gene expression, sexual dimorphism, sexual selection and condition dependence

This week, I was thinking that we should discuss sexual dimorphism from two different perspectives: a "G-matrix" perspective and a gene expression perspective. The two different papers I have chosen hopefully shed different light on sexual selection and the process of sexual selection. The two papers show how sexual selection might leave a signature, either on the molecular level (the first paper) or on the trait-level (the second paper).

The first paper I would like to discuss is from Locke Rowe's group at University of Ontario (Canada), and you can download it here. I heard Locke give a talk about this at the European Evolutionary Biology Meeting ("ESEB") in Italy in August last year, and I already then thought that this was a very interesting subject.

In particular since most of us (at least me!) are not particularly interested in these novel molecular tools per se, but rather wish to understand how they can be used to illuminate problems and processes in phenotypic evolution, at the whole-organism level, I was thinking that we could get some idéa of how transcriptomics might be used to achieve this goal. Hopefully, we will have a good discussion about this on this coming lab-meeting.

The second paper is a more tradition quantitative-genetic study of intersexual genetic correlations by Steve Arnold's group, and this other paper can be downloaded here.

We meet at the usual time and place, i. e.:

Where: "Darwin" room, 2nd floor (Ecology Building)
When: Wednesday, May 5, at 10.15.