Okinawa Integrative Biology Course
Date
Location
Description
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5/26 (Sun) 9:00-12:00 |
University of Texas at Austin
Application of meta-analysis to the study of biological impacts of climate change Ever-increasing strength of anthropogenic global warming has motivated study of responses in biological systems to rapid climate change. There has been a pressing need to develop and identify methodologies that ensure scientific rigor in the detection of biological responses and correct attribution of those responses to climate change vs. other possible anthropogenic or intrinsic factors. However, long-term field data on wild species and ecosystem properties provide, of necessity, only a correlational relationship with between biological changes and diverse potential drivers. Likewise, standard meta-analysis methodologies are designed for analyzing data from controlled experiments. Therefore, methodological innovations have been developed to increase scientific rigor in identifying and setting standards for conducting field studies of climate change impacts and interpreting long-term historical biological data. The constraints and benefits of applying meta-analysis to these questions will be presented, and some additional approaches using biological fingerprints (or signatures) of responses uniquely attributable to climate change impacts will be discussed. |
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5/26 (Sun) 13:00-16:00 |
Kyusyu University
Modeling adaptation in evolutionary ecology In evolutionary ecology, there are many tools to understand the adaptation of organisms, ranging from the optimization, dynamic optimization, game, stochastic decision making, to quantitative genetics and adaptive dynamics. After reviewing some of these, I will talk on the following two systems in more detail.
[1] Evolution of masting -- synchronized and intermittent reproduction of trees. Trees in mature forests often show intermittent reproduction (masting), synchronized over a long distance. According to the dynamics of the resource reserve of individuals, trees can show a large between-year fluctuation in the seed crop even in a constant environment. Reproduction of different trees may be synchronized if fruit production is limited by the availability of outcross pollen. We study conditions for masting to evolve. Based on the analysis of invasibility of mutants, we confirm that for the evolution of masting, the seedlings (young plants) need to survive for multiple years. In addition, specialist seed predators promote the evolution of masting.
[2] Evolution of stalk/spore ratio in a social amoeba: cell-to-cell interaction via a signaling chemical shaped by cheating risk.
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5/27 (Mon) 9:00-12:00 |
University of Texas at Austin
Patterns of species' association in space and time: an example from butterflies and plants Evolution of microbes can be readily studied by experiment; that of larger organisms with longer generation times is mostly studied by inference. However, a persistent researcher who is not easily bored can study evolution of macro-organisms by applying a combination of observation and experiment and gathering large quantities of data at diverse spatial scales across several decades. I have used this approach for the past 45 years to document a diversity of evolutionary and ecological changes in the associations between a single insect species, a butterfly, and its host plants, working at the scales of metapopulations occupying tens of square kilometers and across a landscape of 1,000 x 300 km. By this means I and my collaborators have been able to document a diversity of evolutionary and ecological changes in the associations between the insect and its hosts.
My principal interest is in understanding the mechanisms by which insects come to be distributed across landscapes on particular plants and the processes by which these patterns change over time. The choice of plants by herbivorous insects is of practical interest in two ways. First, because we compete with insects for food and, second, because we choose insects as agents of biological control, to deal with exotic weeds. In the first case evolution of insect diet creates problematic novel pests and in the second, it risks thwarting our intentions, since we have to hope that the introduced insects will show neither the behavioural plasticity nor the evolutionary agility to eat plants that we don't intend them to eat. Host choice by insects also has conceptual interest as a driver of natural evolutionary and ecological patterns and processes. |
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5/28 (Tue) 9:00-12:00 |
Indiana University
MUTATION, DRIFT, AND THE ORIGIN OF SUBCELLULAR FEATURES Understanding the mechanisms of evolution and the degree to which phylogenetic generalities exist requires information on the rate at which mutations arise and their effects at the molecular and phenotypic levels. Although procuring such data has been technically challenging, high-throughput genomic sequencing is rapidly expanding our knowledge in this area. Most notably, information on spontaneous mutations, now available in a wide variety of organisms, implies an inverse scaling of the mutation rate (per nucleotide site) with the effective population size of a lineage. The mutation rate also appears to be inversely related to the amount of the genome allocated to cellular functions. The argument will be made that this pattern naturally arises as natural selection pushes the mutation rate down to a lower limit set by the power of random genetic drift rather than by intrinsic molecular limitations on repair mechanisms.
This drift-barrier hypothesis has general implications for all aspects of evolution, including the performance of enzymes and the stability of proteins. The fundamental assumption is that as molecular adaptations become more and more refined, the room for subsequent improvement becomes diminishingly small. If this hypothesis is correct, the population-genetic environment imposes a fundamental constraint on the level of perfection that can be achieved by any molecular adaptation.
Additional examples consistent with this hypothesis will be drawn from recent observations on the transcription error rate and on the evolutionary of the oligomeric states of proteins. We have recently developed a novel technique for estimating the rate of base misincorporations into transcripts, showing that this error rate is up to 105 times higher than the replication-error rate in several prokaryotic and eukaryotic taxa. In addition, we have recently developed the hypothesis that the complexity of protein architecture (specifically, the numbers of subunits contained with multimers) evolves as an effectively neutral trait, with species often carrying out the same tasks with substantially different quaternary structures of proteins.
Finally, in the above context, I will discuss the evolution of layers of surveillance mechanisms within cells, demonstrating that the emergence of what might seem like robust cellular features endow the organism with no long-term selective advantage, while also increasing the cost of maintaining overly complex features. The general theory presented, in combination with empirical observations, exemplifies the type of work that is necessary for the development of a meaningful field of evolutionary cell biology.
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This workshop is open to OIST students and staff. Please contact Sasha for more information, and see our web site for more details.
Intra-Group Category
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