Linking micro- and macroevolution: do genetic constraints predict phenotypic divergence?
(National Science Center UMO-2015/18/E/NZ8/00716)
The goal of this project is to contribute towards the understanding of how genetic architecture (the structure of the mapping from genotype to phenotype) affects the evolution of quantitative traits. According to quantitative genetics theory, the evolution of phenotypic traits depends on the strength of selection and the amount of genetic variation. However, part of this variation maybe constrained by correlations with other traits that are under conflicting selection regimes. In consequence, the ability to respond to selection (evolvability) may be limited, even if a trait has high heritability. However, the extent to which genetic architecture limits phenotypic evolution remains an open question. Likewise, it is unknown whether it affects only evolution on the short time scale and is easily overcome by selection, or if the genetic architecture is an important long-term determinant of the direction of evolution. In this project we aim to answer these questions using two plant species from the family Apiaceae, Daucus carota and Ferula communis, as a model system. If genetic architecture influences the direction of evolution, the differences between populations should conform to the directions of the highest evolvability. Both species are characterized by different distributions and contrasting levels of phenotypic variation. This disparity will be used to test whether our hypothesis can be generalized to organisms with very different patterns of trait divergence. We intend to apply comparative phylogenetic methods based on Ornstein-Uhlenbeck models to verify if the genetic architecture is reflected in the history of the group. We assume that traits should adapt faster to changing conditions if they exhibit high evolvability. These analyses will be done on a dated phylogeny of Daucus (<10 million years) and Ferula (<6 Ma), and on the entire tribe Scandiceae (<35 Ma) to which both genera belong. This will determine the time frame in which the impact of genetic architecture is the most influential. However, phylogenetic comparative methods based on Ornstein-Uhlenbeck models are under-developed both theoretically and practically. Therefore, we also intend to improve existing models.
Next-generation systematics for challenging taxa: unravelling phylogeny and species delimitation in the subfamily Miltogramminae (Diptera: Sarcophagidae).
(National Science Center UMO-2015/17/B/NZ8/02453)
Despite the rapid development of molecular methods, morphological criteria remain the main tool for species delimitation in many groups of organisms. However, morphology-based delimitation may omit real evolutionary processes (e.g. convergence, cryptic diversity). Recently, methods based on coalescent models have been applied for identification of independently evolving lineages. In addition, molecular identification based on easy-to-obtain mtDNA markers (DNA barcoding) is widely used. In this project, we will test whether morphological and coalescent methods provide congruent results and compare these with species delimitation based on barcode sequences. These issues will be tested using members of three genera from the subfamily Miltogramminae (Diptera: Sarcophagidae). These flies are an example of recent rapid radiation. The members of Miltogramminae are defined exclusively based on morphology; species among and between genera differ by subtle characters, likely under strong natural selection. The exclusively morphology-oriented approach to taxonomy in this group has resulted in alternative taxonomic systems, each with different species concepts. The highest species diversity of our chosen genera is in Middle East and Central Asia, where dozens of morpho-species occur sympatrically. Hence, this area is an ideal natural laboratory for testing species boundaries and gene flow between different morphotypes. In this project we will answer the following specific questions: (1) Is coalescent-based species delimitation congruent with morphological delimitation of species? (2) Are delimitation results similar when alternative methods are employed using competing software tools? (3) Which traits are most informative for species delimitation and shared across the three studied genera? (4) Is there cryptic diversity in Miltogrammine genera which can be detected with morphological markers? (5) Is the COI barcode inference concordant with results based on the nuDNA species tree and comparative morphology? If not, what is a source of this incongruence (e.g. hybridization, incomplete lineage sorting).
Community assembly across temporal and spatial scales: unifying colonization and competition approaches.
(National Science Center 2014/13/B/NZ8/04681)
This proposal deals with a long standing and still unresolved question in community ecology: How do ecological communities assemble?
Recently developed analytical techniques now allow to study and reconcile contrasting hypotheses about patterns of species occurrences predicted by assembly rule theory and the principle of competitive exclusion.
The present application intends to deal with highly resolved local and regional data on species co-occurrences, environmental correlates and species interactions. It has three main tasks. The first task aims at developing a theoretical framework that predicts patterns of species co-occurrences and dominance distributions from habitat features to result in precise and consistent starting hypothesis about spatial distributions and diversity. The second task intends to map understorey forest plant communities quantitatively on replicated plots and to compile necessary data on soil and microclimate conditions, ecological traits, phylogeny, pool sizes, and, as far as possible, colonisation abilities. These data allow to test the hypotheses derived from task 1. Task 3 intends to analyse four global and one local data set to test our hypotheses at different spatial scales.
This project is caried out in collaboration with Werner Ulrich