Person: Pennings, Pleuni
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Pennings
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Pleuni
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Pennings, Pleuni
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Publication Evidence of Adaptation from Ancestral Variation in Young Populations of Beach Mice(Wiley-Blackwell, 2012) Domingues, Vera S.; Poh, Yu-Ping; Peterson, Brant K.; Pennings, Pleuni; Jensen, Jeffrey D.; Hoekstra, HopiTo understand how organisms adapt to novel habitats, which involves both demographic and selective events, we require knowledge of the evolutionary history of populations and also selected alleles. There are still few cases in which the precise mutations (and hence, defined alleles) that contribute to adaptive change have been identified in nature; one exception is the genetic basis of camouflaging pigmentation of oldfield mice (Peromyscus polionotus) that have colonized the sandy dunes of Florida's Gulf Coast. To quantify the genomic impact of colonization as well as the signature of selection, we resequenced 5000 1.5-kb noncoding loci as well as a 160-kb genomic region surrounding the melanocortin-1 receptor (Mc1r), a gene that contributes to pigmentation differences, in beach and mainland populations. Using a genome-wide phylogenetic approach, we recovered a single monophyletic group comprised of beach mice, consistent with a single colonization event of the Gulf Coast. We also found evidence of a severe founder event, estimated to have occurred less than 3000 years ago. In this demographic context, we show that all beach subspecies share a single derived light Mc1r allele, which was likely selected from standing genetic variation that originated in the mainland. Surprisingly, we were unable to identify a clear signature of selection in the Mc1r region, despite independent evidence that this locus contributes to adaptive coloration. Nonetheless, these data allow us to reconstruct and compare the evolutionary history of populations and alleles to better understand how adaptive evolution, following the colonization of a novel habitat, proceeds in nature.Publication Geographic distribution of the anti-parasite trait “slave rebellion”(Springer Nature, 2012) Pamminger, Tobias; Leingärtner, Annette; Achenbach, Alexandra; Kleeberg, Isabelle; Pennings, Pleuni; Foitzik, SusanneSocial parasites exploit the brood care behavior of other species and can exert strong selection pressures on their hosts. As a consequence, hosts have developed defenses to circumvent or to lower the costs of parasitism. Recently, a novel, indirect defense trait, termed slave rebellion, has been described for hosts of a slave-making ant: Enslaved Temnothorax longispinosus workers reduce local parasite pressure by regularly killing pupae of their obligatory slavemaking parasite Protomognathus americanus. Subsequently, growth of social parasite nests is reduced, which leads to fewer raids and likely increases fitness of neighboring related host colonies. In this study, we investigate the presence and expression the slave rebellion trait in four communities. We report its presence in all parasitized communities, document strong variation in its expression between different geographic sites and discuss potential explanations for this observed variation.Publication Raiders from the sky: slavemaker founding queens select for aggressive host colonies(The Royal Society, 2012) Pamminger, T.; Modlmeier, A. P.; Suette, S.; Pennings, Pleuni; Foitzik, S.Reciprocal selection pressures in host-parasite systems drive coevolutionary arms races that lead to advanced adaptations in both opponents. In the interactions between social parasites and their hosts, aggression is one of the major behavioural traits under selection. In a field manipulation, we aimed to disentangle the impact of slavemaking ants and nest density on aggression of Temnothorax longispinosus ants. An early slavemaker mating flight provided us with the unique opportunity to study the influence of host aggression and demography on founding decisions and success. We discovered that parasite queens avoided colony foundation in parasitized areas and were able to capture more brood from less aggressive host colonies. Host colony aggression remained consistent over the two months experiment, but did not respond to our manipulation. However, as a fifth of all host colonies were successfully invaded by parasite queens, slavemaker nest foundation acts as a strong selection event selecting for high aggression in host colonies.Publication Standing Genetic Variation and the Evolution of Drug Resistance in HIV(Public Library of Science, 2012) Pennings, PleuniDrug due to mutations that were present before treatment starts or due to mutations that occur during treatment. The relative importance of these two sources is unknown. Resistance can also be transmitted between patients, but this process is not considered in the current study. We study three different situations in which HIV drug resistance may evolve: starting triple- drug therapy, treatment with a single dose of nevirapine and interruption of treatment. For each of these three cases good data are available from literature, which allows us to estimate the probability that resistance evolves from standing genetic variation. Depending on the treatment we find probabilities of the evolution of drug resistance due to standing genetic variation between 0 and 39%. For patients who start triple-drug combination therapy, we find that drug resistance evolves from standing genetic variation in approximately 6% of the patients. We use a population-dynamic and population-genetic model to understand the observations and to estimate important evolutionary parameters under the assumption that resistance remains a major problem for the treatment of HIV. Resistance can occur treatment failure is caused by the fixation of a single drug resistance mutation. We find that both, the effective population size of the virus before treatment, and the fitness of the resistant mutant during treatment, are key-parameters which determine the probability that resistance evolves from standing genetic variation. Importantly, clinical data indicate that both of these parameters can be manipulated by the kind of treatment that is used.