It's always good to start the day with sex. Alas, today we were only talking and thinking about it.
One of the big mysteries in evolutionary biology has been how sex evolved. John Maynard Smith pointed out in the 1960s that it really shouldn't have - there's a huge cost to any gene (because with sex it only has a 50% chance of being passed on), so a modifier that stops sex and have a 100% chance of being passed on will be fitter. Since then a lot of people have been worrying about this problem. In her plenary talk, Sally Otto talked about recent work that suggests we are close to a resolution of the problem.
There have been a couple of explanations that have been around for some time. The first is that sex helps evolution because it breaks up bad combinations of genes, particularly when the disadvantages are magnified, so that the cost of carrying two bad genes is more than the cost of carrying one bad gene twice (technically this is called epistasis). This does give sex and advantage, but it's so small, and only occurs in limited and unlikely conditions.
The second explanation is the Red Queen hypothesis, again. A species is being subjected to all sorts of attacks (pathogens, parasites etc.), which are co-evolving with them, so there is a constant arms race (this is the Red Queen bit). A species evolves defences, and sex can help combine them together, to increase the speed at which the species runs away from its enemies. This has some empirical support, but Otto showed that the theoretical results suggested it only worked under a narrow set of circumstances.
She then introduced a third idea - to look at finite populations. All of the previous work she had presented had been done assuming infinite populations. But in a finite population gene combinations can be combined randomly by genetic drift, and also not every combination of genes will be present in the population. Sex can then work to combine gene combinations and give an advantage. Adding the Red Queen improves the advantage (and I suspect that any sort of environmental variation will give an advantage to sex, more work needs to be done etc.).
After the plenary I ran off to the session on integrating evolution and ecology. Lots of different things. Carol Eunmi Lee talked about a lot of work on invasing species (err, were they isopods? Something small and aquatic anyway), and suggested that species that invade tend to live in more variable environments in their core ranges (there was more than this, but I turned off during the physiology). Virpi Lummaa talked about a huge data set on agricultural Finns (the church has kept the records on births marriages and deaths for over 200 years, so they put a few of them in a database), looking at twins. She showed that a female twin is less fit if her sibling was male, and that this was due to conditions in the womb (because it persisted even if the sibling died in the first three months of life).
After the sessions there was the ESEB business meeting. As always with these things, some of it was interesting, some just needed to be said (e.g. the accounts). A couple of interesting things appeared from the meeting - the SSE (our US counterparts) wanted to orgnaise a joint meeting. One option had been to have it in 2011, when there should be an ESEB meeting. Nobody liked that, but the second option was to to have a meeting in 2012 in Canada. This looks like the option that will be followed up, so we'll see what happens. The other thing is that there will be a new journal starting next year called Evolutionary Applications.
Today's the last day, and is followed by the banquet. Tomorrow I have to get an early train to go to Gotland, so there may not be any report for a few days.
Saturday, 25 August 2007
It's always good to start the day with sex. Alas, today we were only talking and thinking about it.
Friday, 24 August 2007
A short day today: there are excursions in the afternoon, as well as several barbequeues (including the one I attended).
But before then we had to "work". The plenary was given by Michael Majerus. He talked about the classic peppered moth example of evolution. The original story is well known, but some of the original work by Kettlewell has been criticised, and a book appeared a few years go which accused Kettlewell of fraud. The book has been panned (and when I read it, I wasn't convinced either), but is used by creationists as the basis of one of their assaults on evolution. Actually, there are some good criticisms of Kettlewell's work, so Majerus decided to re-run the experiments (actually not quite - he would have needed a wood which is still polluted) but redesigning them to take the criticisms into account.
Majerus ran his studies for 6 years in his field site (actually his back garden), and also trapped moths near by to look at the change in the melanic form. The long and the short of it is that he replicated Kettlewell's results (qualitatively - after half a century we would expect some differences). So, it looks like Kettlewell was right after all (to the surprise of nobody in the room). We then had a sermon about how we need to keep faith and belief out of science, and that the peppered moth is such a good example for education that it should be used. Not really controversial for this audience, but good to rally the troops.
The parallel sessions weren't too interesting for me, but I went to Jim Mallet's talk on mimicry in Heliconius and other butterflies. This is a story that's been going on for years, and I look in on it when I'm at meetings. The latest thing is that they are thinking about how mimicry can affect speciation - mimicking a distasteful species means you don't get eaten, and different populations mimic different species in different areas. But wing colouration also affects mating behaviour (quite simply, the male can't recognise the female that's the 'wrong' mimic), so that could lead to reproductive separation and speciation. SO, they're now looking for hybrids between species, and also into the genetics and development of wing colour. More next time.....
In the afternoon I didn't go on an excursion, instead we had a barbaqueue in the house I'm staying (err, actually outside the house). Lots of beer drunk, a new wealth index invented, and just after a pregnant lady sat down next to her, Vilppu asking "So, how do you get the sperm?"
Thursday, 23 August 2007
Now we're seriously into the conference: the first full day of talks (without poster sessions, excursions etc.).
We kicked off with Douglas Schemske talking about evolution in the tropics. It's well known that the amount of diversity in the tropics is huge compared to the more temperate parts of the world. People have surveyed forest plots a few hectares large, and found a huge number of tree species - more than in the whole of North America. This has puzzled people, and there are several theories being kicked round. Schemske was arguing that the diversity is driven by biotic interactions - i.e. predators eating prey, plants living in a mutualistic interaction with ants, pathogens living off hosts etc. His claim is that in colder regions, the main threats come from abiotic conditions (cold, frost, drought etc.), so species invest in reactions to those.
In the tropics, the environment isn't from inclement weather, but from other species, so a species has to adapt to overcome its predators, pathogens etc. This leads to an arms race - the predators and pathogens are also evolving as well. This sort of interaction is called the Red Queen hypothesis, from Alice Through the Looking Glass, where the Red Queen says
Now, here, you see, it takes all the running you can do, to keep in the same place.
Species have to keep evolving to keep half a step ahead of their competitors. In different parts of a species' range, the populations will be assailed by slightly different competitors, so will evolve in different ways (mimicry rings are a great example, wander around Jim Mallet's pages for a bit and you'll see why). This can then lead to speciation.
This sounds all well and good - more biodiversity leads to more biodiversity, but how does it get started? Schemske didn't address this problem. He did mention an alternative hypothesis to his, which is that the World has been tropical for most of the time there has been life, so the tropics may just be older, and hence had more time to produce more biodiversity, which has then exploded.
After the plenary, I spent most of my day listening to talks about mapping genes. A lot of them were "I got some DNA from a cross/several crosses, made a linkage map, compared it to once from a model species, and then mapped some genes". The quality of the maps improved over the day, and people found genes (a couple I wasn't convinced about, but hopefully they'll check further). One interesting point came from Hopi Hoekstra. She has been looking at genes for coat colour in a mouse, and found a locus affecting variation in the trait, and then found out that it wasn't in the protein sequence, it was in the regulatory region (i.e. the part of the genome that controls when a gene is switched on and off). I liked this, as I've been wondering if regulatory sequences will appear in these sorts of analyses.
The non-mapping talk I went to was by Leonard Nunney. He has been working on Haldane's dilemma, which sets a limit on the rate at which a population can evolve in a worstening population. He put this into the context of the Red Queen, because her full reply to Alice is:
Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!
So, not only does one have to run as fast as you can to stay in the same place, but if the environment is changing, you have to run even quicker. Actually, this was the point of the original Red Queen paper (by Van Valen): that extinctions occur at roughly a constant rate, which suggests that species aren't adapting any better to the environment, presumably because the environment keeps on changing.
The evening presentation was by Steve Stearns (now of Yale) on how the ESEB was set up. Basically, a publisher wanted him to start a journal, but wanted a society behind it. So, he had to set up a society too...
Wednesday, 22 August 2007
Below the fold is the best poster ever seen at an evolutionary biology meeting.
Email Chris and tell him you saw the poster on the web, and think it's brilliant (but don't tell him where you found it. Please).
Today the conference started for real. We kicked off with a plenary talk by Sean Carroll (of Endless Forms Most Wonderful fame), talking about evo-devo, and how what's important is the regulation of genes involved in development, not their actual protein product. I've read about some evo-devo, but now I feel I understand the point (I might blog more on this later).
After the plenary there were parllel session. Of course, there are always more than one that look interesting, so I started in the evolution in complex environments session. This kicked off with a nifty talk by Graham Bell, talking about adapation in bacteria. His starting argument was that the classic experiments of bacterial dynamics set up simple environments - one or two substrates, one or two clones etc. But this isn't the sort of environment the bacteria live in. He then talked about some experiments with many clones, in more complex environments (lots of substrate etc.).
Classically, we might expect to see trade-offs and specialisation in the use of different substrates, so that a clone that prefers glucose will be worse at using fructose, for example. But they didn't see this - instead everything just adapted equally. His conclusion was that the bacteria were "overlapping incomplete generalists": they could use a wide variety of resources reasonably well. The rest of the sesion was less interesting - playing with models and drawing pairwise invasability plots (beloved of adaptive dynamicists, obscure to everyone else).
After coffee (during wich I explained Genetics 101 to a senior professor), I went to the evolutionary epidemiology session. I missed the first half of the first talk because I didn't realise it was in another building (but did have a fascinating chat with a physchiatrist). The talk that was mostly interesting for me was Anna-Liisa Laine's. She's in Helsinki, she works on powdery mildew, but most of the times I see her, we discuss something else. So this was a good chance to find out what she's been doing.
Lunch was in a variety of restaurants - I was in Il Forno, where we didn't fornicate (perhaps they had better luck in Hörs).
After lunch, more epidemiology. The final talk was about where food poisoning comes from: using molecular tools to compare bacteria from food poisoning to samples from the environment and from animals (chickens, sheep, cows etc.). They threw some neat statistics at the problem, and could show that most of the poisoning came from meat, and not the environment. So, no need to wash your hands after playing with pigeon shit, then!
After this was the first poster session. This is hell if you're a student. You stand by a poster that you've sent two weeks on as people walk past thinking "can't be bothered - too much text on it". I don't have a poser (ha!), so I wondered round looking for the two or three interesting ones. I found a few - one using a really simple model for mating strategies - number of mates, variation in mating success etc. (a Dirichlet-multinomial. OK, simple if you're a statistician). There was also another poster that deserves its own entry....
That was the end of the official session - it was followed by the informal session, chatting to people, having lunch with the folks from Jyväskylä. For once I avoided the pub.
So, more today - looks like QTLs and conservation genetics. Read more!
Tuesday, 21 August 2007
Well, I got here.
Typically for a conference, I met a bunch of other people going to the conference as well. Some I knew, some were rather obvious because they were carrying long plastic tubes (for posters). Monday was just for registration and a reception, so I did a bit of networking - catching up with old friends, meeting people who send me blank emails, that sort of thing. There are 1300 people here, so I guess I won't see everyone.
The conference abstract book is huge, about 600 pages of A4.
This is just silly: they have had to print out 390 000 sheets of paper (anyone know how much forest that is?). If they were piled one on top of another, they would be 55m high (that's as tall as, err, a very high building. For reference, Uppsala cathedral is 118m high).
So, today we start with the talks etc. We kick off with a plenary (Sean Carroll), and then 5 parallel sessions. Of course, I want to go to two of them.
Oh, and we also found the pub.
Sunday, 19 August 2007
Tomorrow I'm off to Uppsala to the ESEB meeting, after which I'll be in Gotland for another (smaller) meeting. I'll try and blog (the place I'm staying in Uppsala has wireless), but I might be too busy working on my comparative study of Nordic beers.
So all three of you regular readers should expect an even less regular service. And if anyone's in Uppsala as well, then say hello if you see me!