Ádám Kun
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- Evolution of cooperation in a heterogeneous environment
- The evolution of the RNA world
- Metabolic networks analysis, the evolution of metabolism
Overview of former research rojects
- By a comparative study of two real ribozymes we have shown that the critizal error rate above witch information could not be maintained is an order of magnitude higher that assumed for nearly 30 years. Accordingly, a per base copying fidelity of 0,999 would allow the maintenance of a genome of 7000 nucleotides, which could consist of 100 genes of the length of a tRNA. This would be long enough for a ribo-organism to have a rich metabolism. (Kun, Santos, Szathmáry 2005).
- We have shown that the middle letter of the genetic codes strongly correlates with the catalytic activity of the amino acids, with those having A (His, Lys, Asp, Glu) or G (Arg) in the middle of their triplet being the most active. This finding hints at the order of amino acid incorporation to the code. (Kun et al. 2007)
- We have we investigate the asynchronous version of the Snowdrift (or Chicken) game in which, contrary to the rather unrealistic assumption of simultaneous moves, one of the players acts first, and the other responds by knowing its decision. The Snowdrift game adequately describes many situations, e.g. cooperative hunting, group foraging, territorial defence, predator watching or parental care. We found that both a synergistic effect of cooperation (i.e. cooperative effort is better than the sum of the individual efforts) and population structure (low dispersal, spatial confinement or group formation) are crucial for mutual cooperation to emerge. Otherwise, only one of the players will carry the burden of cooperation. (Kun Á., Boza G. and Scheuring I. 2006)
- We have shown that random changes in the interaction structure of individuals are detrimental for the evolution of cooperation. This detrimental effect is the smallest if the interaction network is a scale-free network. If individuals could actively end association with those that exploited them, then cooperation evolves more readily. Such assortative partner choice can counterbalance the unavoidable fluctuation in network. (Kun and Scheuring 2009, 2010)
- We have studied multi-tiered primate societies from the view point of cooperation. A simple model of group living primates that can cooperate to defend mates and territory is presented. Depending mostly on the cost of cooperation, the strength of intergroup selection and strength difference between dominant and subordinate individuals different social structures emerge, such as loose groups, cooperative breeders / helpers, multi-tiered societies and multi-male multi-female societies. (Kun and Scheuing (invited to the International Journal of Primatology))
- Based on a novel discrete mathematical method we have proposed new metrics for the comparison of vegetation patterns than could detect characteristic areas better than established methods. (Ittzés et al. 2005).
- We have shown that there are sequence features that are specific to the class I and class II tRNAs, a classification, which is based on the aminoacyl tRNA synthetases. Traditional techniques had looked for similarities in sequences, but very few if any exist. We have demonstrated that there are nucleotides that are strictly absent at certain positions. This information is the class-specific tRNA sequence feature. (Jakó et al. 2007)
- Based on existing bioinformatical data, we have shown that intermediate metabolism is autocatalytic for the analyzed 7 Eubacteria, one Archaea and one Eucaryote. Metabolism was autocatalytic with respect to ATP in all cases. We have proved that other organism and environment specific autocatalytic molecules also exist in the form of conenzymes (NAD, CoA, THF quinones) and sugars. These results help us to understand the limits of artificial cell synthesis and the prebiotic evolution of metabolism. (Kun, Papp, Szathmáry 2008).
- I have studied during my PhD studies the advantage of physiological integration among modules (ramets) of clonally (vegetativelly) reproducing plants. I have employed state-of-art spatially explicit modelling techniques. I have shown that none of the heterogeneity components (grain, contrast, frequency of favourable sites, patch size, frequency of patch quality change) in itself could explain the outcome. This shows that the determination of heterogeneity components is key to understand ecological processes. Physiological integration (i.e. resource sharing) is advantageous in changing, coarse grained with high contras and either very poor or very rich habitat (Oborny et al. 2000,2001; Oborny, Kun 2002).
- In static environment with parse distribution of favourable patches the strategy that does not share its resource among their modules (splitter) cannot spread in the environment, which can be explained by percolation theory. A small amount of environmental change alleviates this barrier to spread (Kun, Oborny 2003).
- We have developed a general framework of studying division of labour among clonal plants in environments, in which experimental studies are practically unfeasible. We have shown that phenotypic plasticity in allocating to shoot or root is advantageous in a very wide range of habitat (Magyar et al. 2009).
- I have shown in a spatial metapopulation model that intermediate frequencies of landscape change maximize metapopulation size. This result has relevance for conservation ecology and management. (Kun, Oborny, Dieckmann 2009)
- While most papers in theoretical landscape ecology study the properties of static landscapes, I have shown that the introduction of temporal change is not difficult. In particular, I have studied the dynamics of the most basic of artificial landscapes, the percolation map. Using this model, I have shown that a habitat gets fragmented at a maximal rate when only about 40% of it remains. (Kun Á., Oborny B. and Dieckmann, U. Toward a neutral model in fluctuating landscapes (in prep.))
- Spatially explicit models of population dynamics even if they consider environmental heterogeneity at all, focused only on spatial heterogeneity, albeit experimental and theoretical investigations show that temporal heterogeneity is also very important. In a methodological paper I have described algorithms for the generation of heterogeneous landscapes that can couple these two aspects of heterogeneity within the same framework. (Kun 2007)
- Dispersal is advantageous in many different ecological situations. However, the key question what kind of dispersal strategy is optimal in a particular situation has remained unanswered. We studied the evolution of density-dependent dispersal in a coupled map lattice model, where the population dynamics are perturbed by external environmental noise. We used a very flexible dispersal function to enable evolution to select from practically all possible types of monotonous density-dependent dispersal functions. We treated the parameters of the dispersal function as continuously changing phenotypic traits. We found that irrespective of the cost of dispersal and the strength of environmental noise, this strategy leads to a very weak dispersal below a threshold density, and dispersal rate increases in an accelerating manner above this threshold. (Kun Á. and Scheuring I. 2006.)