Posts by ullergroup

Winter is coming!

Winter is not really the best time of year in Skåne, unless you really enjoy all those different shades of grey. To get a feeling of a proper Swedish winter, the group packed their warmest clothes (and triple pairs of socks) and headed up to Sunne, where Tobias was born and raised. Winter in Värmland is the real thing – snow-covered forests, ice-covered lakes and the hope of a rare wolf spotting.

Tobias’ parents opened up their whole house for us, and his brother served as the cross-country skiing coach and ‘vallachef’. People from eight nationalities put on their skis – some for the very first time – and headed out to the tracks. Everybody had healthy rosy cheeks and slightly frozen toes by the end, and incredibly nobody was injured! In fact, Yang and Mara both proved to be natural talents at skiing, despite the limited snow cover in Chengdu and Murcia. This was extra impressive considering that Yang broke his ‘low Celsius record’ two days in a row and had only once seen this much snow before – an occasion he described as “catastrophic”!

Ice-fishing released a lot of creative forces in the group. Pumping up a groovy atmosphere in the glorious sunshine, Illiam and Alfredo managed to pull up several perch while the others skied across the lake. Back at the house, an old snow racer could of course not be resisted. The greatest daredevil and air-time record-setter was Reinder, perhaps due to limited childhood experience of what happens when you go down hills really fast…

After these lovely but chilly outdoor activities we enjoyed cosy evenings around the fireplace with games and wine. Alex turned out to have the best strategic skills whereas Illiam proved to have the gift of storytelling (a.k.a. lying). Nathalie turned out to be an amazing air pilot, Hanna a master of skull-drumming and Tobias – well, he was still the real Harry even when everyone else had lost track.

Many thanks to the Uller family for an amazing weekend. We’ll see you again next time… ;-)!

 

 

 

 

 

 

 

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Live bearing promotes the evolution of sociality

Some lizards and snakes tend to hang out in family groups, not unlike the more familiar social groups of birds and mammals. Our recent study, headed by Ben Halliwell and Geoff While and published in Nature Communications, show that the evolution of social grouping is much more likely to have happened in lizards and snakes that give birth to live young. There could be a number of reasons that transitions to sociality are more common for live bearing species.

The most obvious one – and the theoretical rationale behind this study – is that giving birth to live young makes interactions between parents and offspring more likely than in species that lay eggs. And interaction among kin, in turn, is what causes natural selection for group living.

(C) Dale Burzacott

Some lizards – in particular the Egernia – in fact have quite complex kin-based social structures. As expected, such groups have almost exclusively evolved in live-bearing lineages. Interestingly, egg guarding does not seem to have the same positive effect on the evolution of sociality. Maybe this is because the ecology needs to be right as well to select for delayed dispersal and parental tolerance of offspring. For the full story, please download the paper here.

 

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Evolutionary adaptation to climate: same same, but different

A new study published in Evolution – headed by Nathalie – reveals how embryonic gene expression patterns change as non-native lizards adapt to cool climate.

Populations adapting independently to the same environment provide important insights into the repeatability of evolution. In the 20th century, common wall lizards (Podarcis muralis) from southern and western Europe were introduced to England, north of their native range. We have previously shown that non-native populations of both lineages have adapted to the shorter season and lower egg incubation temperature by increasing the absolute rate of embryonic development.

In this new study, we show that embryos from non-native populations exhibit gene expression profiles consistent with directional selection following introduction. However, different genes are affected in lizards from France and Italy. The biological function of these genes are quite similar, though, and consistent with mechanisms that should speed up development. These results indicate that small populations are able to adapt to new climatic regimes, but the means by which they do so may largely be determined by founder effects and other sources of genetic drift.

 

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Heredity in Evolutionary Theory

It may not have escaped your attention that biologists are taking a more inclusive view on heredity these days, regularly referring to epigenetic or behavioural inheritance, for instance. It is often difficult to understand what this means, however, or why it matters. Tobias and Heikki Helanterä take a closer look at heredity in evolutionary theory in a new book from Oxford University Press – Challenging the Modern Synthesis: Adaptation, Development & Inheritance, edited by philosophers of biology Philippe Huneman and Denis Walsh. A pre-print version of the chapter can be found here.

In evolutionary biology, there are arguably four main ways to think of heredity:  as transmission of genes and other ‘particles’, as a phenotypic covariance, as transmission of information, and as the outcome of developmental processes. These are not mutually exclusive, and which one that is adopted or emphasized is partly a pragmatic decision based on the research question at hand (e.g., Tobias regularly makes use of all four), and partly a reflection of one’s conceptual framework (e.g., in some people’s minds heredity can only be genetic and strictly separated from development, and if you think otherwise you are either an idiot or, worse, a Lysenkoist in disguise).

 

When empirical research reveals new mechanisms by which parents influence their offspring – like the persistence of DNA methylation from mother to offspring or offspring learning how to forage from their father – researchers naturally accommodate these findings according to how they think of heredity. But it also leads the odd biologist (and non-biologists) to question the coherence of her current conceptual framework, which is why ‘extra-genetic inheritance’ can be perceived as a challenge to the traditional view of evolution (i.e., the ‘modern synthesis’ – if you do not like this term, just think of a colleague who thinks that all fundamental problems in phenotypic evolution can/should be answered without referring to development). And, as we know, conceptual change can make some new research questions appear more interesting or relevant than they did before, whereas others may fade into oblivion.

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Illiam Jackson joins the group

Target of illiams PhD work – Agnostus pisiformis fossil. Scalebar is 2 mm.

It is often pointed out that there is a strange gap between evolutionary biology and palaeontology. Particularly considering that it is hard to find something so obviously relevant to evolution as the fossil record… Anyway, we now hope to reduce this gap thanks to Illiam Jackson. Illiam did his PhD in palaeobiology in Uppsala under the supervision of Graham Budd (although he likes to point out that his first degree was in Biology). He joins us with a passion for morphometrics, and for making development relevant also to the study of fossils. Illiam will continue his work on plasticity and evolution of trilobite-ish arthropods here at Lund, but he will also – together with Nathalie Feiner – explore if developmental plasticity shapes adaptive radiation of lizards. Welcome Illiam!

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