Wednesday, May 27, 2015

Maternal effects and epigenetics in humans

Elmar Tobi from Leiden University Medical Centre is visiting this week. He will give us an informal overview of his research showing how exposure to poor nutrition during early development affects the epigenome, using the famous longitudinal study of the Dutch hunger winter cohort. In other words, maternal effects, epigenetics, and how they affect health and disease.

The title is: Epigenetic consequences of the Dutch famine

If you want to check out Elmar's papers you can find a list here.

The talk starts at 15.15 on Thursday in Argumentet and will be followed by a trip to the pub later in the afternoon/early evening. There are more good reasons to join because you can also meet Antonio Cordero who just arrived to do a postdoc in Tobias' group. More about him later on this blog.

Friday, May 22, 2015

Coevolution of the sex chromosomes in Drosophila melanogaster

Posted by Jessica Abbott on behalf of Katrine Lund-Hansen

Since I´m leaving next week, I thought I could give a informal talk about why I have been spending so many hours in the lab.
We wanted to quantify coevolution of the two sex chromosomes in Drosophila through intriguing crosses.
Our results have been surprising and we are still trying to understand them, but they seem to have implication for our understanding of sex chromosome evolution,
sexual antagonism, and speciation.
So there is going to be a lot of talk about flies and sex chromosomes.

Same place, same time, I'll bring fika.

Hello and goodbye

Posted by Jessica Abbott

 As anyone who follows this blog will have noticed, we recently gained two new members. However we also lost an old member, Maren Wellenreuther, not too long ago. Maren left EXEB and the Evolutionary Ecology unit a couple of months ago to rejoin MEMEG, as she felt this would be a better fit for her. Although this is of course a loss for us, we respect Maren's decision and wish her the best of luck in her future endeavours!

Monday, May 11, 2015

Introducing new EXEB-members

Last week, two new members started at EXEB in Tobias' group.

Reinder Radersma

I am interested is the dynamic relationship between phenotypes and their environment, and how different solutions have evolved to deal with different levels of variability in the environment. I just started in EXEB to work with Tobias on epigenetic inheritance in water fleas (Daphnia). We will investigate the non-genetic inheritance of tolerance to toxins produced by cyanobacteria. Daphnia have low tolerance in spring, but built up tolerance over the summer. There are studies showing this is non-genetically inherited and there are also indications it might be epigenetic. Before, I worked in Oxford on social behaviour and genetics in great tits. I have looked at the heritability of social network traits and took also a population genetic approach to investigate how space and social structure affect the distribution of genotypes in the population. I did my PhD in Groningen on the ecological and evolutionary consequences of brood sex ratio variation, also in great tits.

Reinder's working on epigenetic inheritance in water fleas (Daphnia)


Hanna Laakkonen

I'm a lab manager in Tobias' group and my tasks vary from general administration to assistance in all the research related things, and also to research itself. I’m defending my PhD on phylogeography of amphi-boreal marine fauna this autumn, in the Finnish Museum of Natural History of Helsinki University. In my doctoral project I studied genetic diversity and phylogeography of boreal and arctic marine fauna, including some thirty invertebrate and thirty fish taxa. Study questions were related to genetic relationships (vicariance, dispersal, cryptic diversity, secondary contacts and introgression) of North Pacific and Atlantic animals, in the timescale from Pliocene to Holocene. In my master’s thesis I studied chronic effects of crude oil to plankton community, and thus I’m also very excited about Reinder’s project. While my background is in phylogeography, especially adaptation to new environments fascinates me, including the ecological drivers and evolutionary mechanisms behind it.

Hanna's a lab manager

Friday, May 8, 2015

Labmeeting: talk on genetics and social behaviour

For next week’s lab meeting I would like to give a presentation of some of the work I have done in the last few years on genetics and social behaviour in great tits.

Two interacting great tits by Shirley Clarke

Title: The interplay between genes and social structure

Many animals regularly engage in interactions with conspecifics. Because those interactions can have fitness consequences, there is scope for selection on social traits. There are however some complications, because individuals change their social environment by interacting and therefore the selection pressures they face change as well. Individuals can also choose their environment by choosing with which individuals they interact. Lastly, social interactions also affect the spatial distribution of genotypes and therefore the local gene pool. I will present work on the great tit population of Wytham Woods (Oxford, UK). We constructed social networks of foraging great tits with automated radio frequency identification techniques. For all years a pedigree was constructed and for some years most individuals were also genotyped on a SNP-chip. I investigated the genetic basis of social behaviour and so-called indirect genetic effects. I also looked at the effect space and social structure had on the distribution of genotypes. I will discuss the results and their broader implications.

Thursday, April 30, 2015

Evolution of U/V sex chromosomes

Posted by Jessica Abbott

Homalothecium lutescens, by

For next week's lab meeting I thought it might be interesting to read a paper about the evolution of sex chromosomes in haploid species. I was recently on the examination committee for Frida Rosengren, who has worked on mosses, a typical group with haploid sex chromosomes. These haploid chromosomes are usually called U and V, to distinguish them from diploid ZW and XY system. The fact that they usually exist in a haploid state leads to some interesting predictions, for instance that degeneration of the male V chromosome should not occur. I haven't read this paper yet but I think it sounds interesting!

Title: The evolution of sex chromosomes in organisms with separate haploid sexes

Abstract: The evolution of dimorphic sex chromosomes is driven largely by the evolution of reduced recombination and the subsequent accumulation of deleterious mutations. Although these processes are increasingly well understood in diploid organisms, the evolution of dimorphic sex chromosomes in haploid organisms (U/V) has been virtually unstudied theoretically. We analyze a model to investigate the evolution of linkage between fitness loci and the sex-determining region in U/V species. In a second step, we test how prone nonrecombining regions are to degeneration due to accumulation of deleterious mutations. Our modeling predicts that the decay of recombination on the sex chromosomes and the addition of strata via fusions will be just as much a part of the evolution of haploid sex chromosomes as in diploid sex chromosome systems. Reduced recombination is broadly favored, as long as there is some fitness difference between haploid males and females. The degeneration of the sex-determining region due to the accumulation of deleterious mutations is expected to be slower in haploid organisms because of the absence of masking. Nevertheless, balancing selection often drives greater differentiation between the U/V sex chromosomes than in X/Y and Z/W systems. We summarize empirical evidence for haploid sex chromosome evolution and discuss our predictions in light of these findings.

Immler & Otto (2015) Evolution 69(3):694-708.

Chance and direction in research

This is re-posted from Andrew Hendry's Eco-Evo Evo-Eco blog. By Jessica Abbott.

Since Andrew Hendry was kind enough to write a guest post about his career path to date, I was invited to return the favour. As with most researchers I know, my career path has been considerably influenced by chance events. In fact, now that I think about it, you can see this effect pretty much as far back as you want to go. Andrew started his story with his MSc work, but I’ve decided to put a bit more focus on the things that got me started on the road to research. I regularly give lectures for high school students, and one of the things they’re often interested in is how I decided to become an evolutionary biologist. Besides, all you have to do is look at my CV to get an idea of the things I’ve done during and after my PhD.

Some people you meet in science ended up there despite the fact that it was never their childhood dream. Others always wanted to be researchers. I fall into the second category. Ever since I was a kid I was interested in science, especially biology and astronomy. I first became interested in evolution when I read a book about it in 6th grade. At that time I didn’t really realize that you could be a professional evolutionary biologist, though, so I never really considered it as a possible career.

By the end of high school I had settled on marine biology as an interesting field. But I didn’t want to work with dolphins! At some point I’d seen a lecture by a local researcher from Trent University, who talked about the development of new cancer treatments from naturally-occurring chemicals (for example taxol, which is derived from yew trees and can be used to treat ovarian cancer). She also mentioned marine sponges, and how they might be a promising subject for similar research since they have effective but relatively non-specific immune function. This sparked my interest as a way to combine research in marine biology with some practical applications. I therefore decided to study marine biology at the University of Guelph during my undergraduate degree.

Suberites domuncula, by Guido Picchetti. Charismatic, no?
It was my first-year introductory zoology class that really made me start thinking about evolutionary biology. Ron Brooks taught the class and basically seemed to completely ignore the material that was supposed to be covered in the course, at least judging by the information we covered in the labs. Instead he talked a lot about evolution and told everyone to read The Selfish Gene. I was a good student, so of course I read it. And it made me realize that this was the sort of thing that I really wanted to work with.

I also wanted to broaden my horizons on a personal level, so I applied to go on an international exchange for my third year. My destination, Lund University in Sweden, was pretty random. I had originally applied to go to Aberdeen or Sydney, because they were the only two places that had marine biology programs (at least among the universities that Guelph had a reciprocal exchange agreement with). But because both these locations were highly popular (meaning only one semester abroad was allowed) and I wanted to go for a whole year, the exchange office suggested some other options. Lund seemed to have the most interesting selection of courses, so that’s where I decided to go, despite knowing basically nothing about the country or the university.

Lund is lovely in the spring.
Once I got to Lund, I really liked it. The classes were small and the material was interesting. Swedes were hard to get to know, but nice once you knew them. It was fun learning a new language. And of course I met my future husband. So rather than go back to Guelph I registered as a student in Sweden for the next year. And near the end of my second academic year in Lund I started a master’s project with Erik Svensson. My choice of project was also somewhat random. Because I was interested in evolutionary questions in general, I wasn’t so picky about the type of study organism. I asked around to find out who had a project that needed a student, and just went with the one that sounded most interesting. That’s how I ended up working on Ischnura elegans. When the opportunity arose to continue working with Erik in the same system, I took it.

As I neared the end of my PhD I started thinking about what to do next. I was never especially enamoured with field work, so I thought it would be fun to try working with a lab-based system. I was interested in the evolution of sexual dimorphism (I’d done a bit of work on sexual dimorphism during my PhD), but also in genetic conflicts. I’d run across Bill Rice’s work on intralocus sexual conflict (then often called ontogenetic sexual conflict) which combined both of these things, but at that point there weren’t so many people working in that area, so it wasn’t really on my radar. Then I went to ESEB in 2005 and saw a talk by Russell Bonduriansky about intralocus sexual conflict. It made me realize that this could be a viable option after all. I therefore got in touch with Adam Chippindale to see about doing a postdoc with him.

Adam’s response was a pretty typical one – he’d love to have me as a postdoc but didn’t have the money to hire me himself. But he was happy to help me out in designing a project so that I could apply for my own funding to go to Queen’s University. I applied to both NSERC and the Swedish Research Council (VR), and was successful with VR. That’s how I got started working on experimental evolution, and Drosophila, a method and a system which I still use today.

When we moved to Kingston we had hoped to stay longer than the two years of my VR fellowship, but when I applied for an NSERC postdoc again (my last chance) I wasn’t successful. The choice was between returning to Sweden with a new repatriation fellowship from VR, or being unemployed and living in my parents’ basement. I think you can guess which was the more attractive choice. That’s how I ended up in Uppsala, working with Ted Morrow. I took my fly populations with me and continued the stuff that I’d done at Queen’s in Uppsala.

I liked the fact that there were a bunch of sexual conflict people in Uppsala, and I liked working with Ted. When my one-year repatriation grant was up, I was lucky enough to be offered a one-year postdoctoral stipend by Klaus Reinhardt, funded by the Volkswagen Foundation. During that period I continued to work in Uppsala, but on a collaborative project with Ted and Klaus. The stipend kept me going until I was successful in obtaining a Junior Researcher Project grant from VR.

Macrostomum lignano mating, by Lukas Schärer.
The Junior Researcher grant let me start up my own small group, and start work on a new study organism, Macrostomum lignano. (The story of how I decided to do a project on Macrostomum is also interesting and much influenced by chance events, but I won’t go into details here. This post is long enough already.) Although I considered staying in Uppsala, in the end I decided to move back to Lund, both for personal and professional reasons. I liked having a lot of people that shared my interest in sexual conflict in Uppsala, but the downside was that it meant that I was just one of many, and that I wouldn’t necessarily bring anything new to the department. Lund was also closer to old friends and my husband’s family. I’ve been working here since 2012.
Looking back, it’s clear that both chance and direction have played a role in my career path. In many ways, I’m exactly where I had hoped I would be at this stage, when I imagined my future as a teenager. I imagined myself working at a good research university (preferably abroad), in a good relationship (maybe kids – not essential), combining research, teaching, and popular science in an enjoyable mix. These things are all true (that’s where the direction part comes in). However exactly what I’m working on and where I am are different than what I expected (that’s where the chance part comes in).
It’s also been a lot harder than I had expected it to be. It’s not like I thought being a researcher would be easy. But being a postdoc with no option to plan long-term, no job security, and a family, was much harder than I had expected. A common theme when senior scientists talk about their career paths is “I just worked on whatever I thought was most interesting, I never tried to think strategically”. I know that PhD students and postdocs can find this a bit frustrating – even if this approach is perhaps a necessary condition for success, it’s probably not sufficient. There’s probably just as many people out there (or more!) who followed their hearts but didn’t get that tenure-track job or key big grant, as the ones who did. I can understand this frustration, because “just do what you think is fun” is not very helpful advice. However, one can also look at it another way. It’s good to have long-term goals in mind (direction), so that you can take the right opportunities as they come up (chance). But if you’re not really enjoying your work while you’re working on it, what’s the point? Don’t spend a lot of time doing things you don’t like just because you think they’re strategic. You might get hit by a bus tomorrow.