Researcher: Sağlam, İsmail Kudret
Loading...
Name Variants
Sağlam, İsmail Kudret
Email Address
Birth Date
5 results
Search Results
Now showing 1 - 5 of 5
Publication Metadata only Phylo-comparative analyses reveal the dual role of drift and selection in reproductive character displacement(Academic Press Inc Elsevier Science, 2019) Miller, Michael R.; O'Rourke, Sean; Çağlar, Selim S.; Department of Molecular Biology and Genetics; Sağlam, İsmail Kudret; Faculty Member; Department of Molecular Biology and Genetics; College of Sciences; 168783When incipient species meet in secondary contact, natural selection can rapidly reduce costly reproductive interactions by directly targeting reproductive traits. This process, called reproductive character displacement (RCD), leaves a characteristic pattern of geographic variation where divergence of traits between species is greater in sympatry than allopatry. However, because other forces can also cause similar patterns, care must be given in separating pattern from process. Here we show how the phylo-comparative method together with genomic data can be used to evaluate evolutionary processes at the population level in closely related species. Using this framework, we WA the role of RCD in speciation of two cricket species endemic to Anatolian mountains by quantifying patterns of character displacement, rates of evolution and adaptive divergence. Our results show differing patterns of character displacement between species for reproductive vs. non-reproductive characters and strong patterns of asymmetric divergence. We demonstrate diversification results from rapid divergence of reproductive traits towards multiple optima under the dual influence of strong drift and selection. These results present the first solid evidence for RCD in Anatolian mountains, quantify the amount of drift and selection necessary for RCD to lead to speciation, and demonstrate the utility of phylo-comparative methods for quantifying evolutionary parameters at the population level.Publication Metadata only Triangulations and quadrangulations of the sphere(World Scientific Publ Co Pte Ltd, 2015) Department of Molecular Biology and Genetics; Sağlam, İsmail Kudret; Faculty Member; Department of Molecular Biology and Genetics; College of Sciences; 168783Thurston proved that the space of non-negatively curved triangulations of the 2-sphere can be parametrized by a quotient of a lattice by a group. We prove his result by a new method. Also we prove similar results for some different families of triangulations and quadrangulations of the 2-sphere.Publication Open Access Genome-wide analysis reveals regional patterns of drift, structure, and gene flow in longfin smelt (Spirinchus thaleichthys) in the northeastern Pacific(Canadian Science Publishing, 2021) Hobbs, James; Baxter, Randall; Lewis, Levi S.; Benjamin, Alyssa; Finger, Amanda J.; Department of Molecular Biology and Genetics; Sağlam, İsmail Kudret; Faculty Member; Department of Molecular Biology and Genetics; College of Sciences; 168783The southernmost stock of longfin smelt (Spirinchus thaleichthys) is approaching extirpation in the San Francisco Estuary (SFE); however, patterns of genetic structure, diversity and gene flow which are vital for management are poorly understood in this species. Here, we use genome-wide data to evaluate population structure of longfin smelt across a broad latitudinal scale across estuaries ranging from the SFE to Yakutat Bay and Lake Washington, and fine scale within the Fraser River and the SFE. Results indicate high genetic structure between major estuaries, fine-scale structure within the Fraser River, and low levels of structure within the SFE. Genetic structure was more pronounced between northern estuaries whereas southern estuaries showed shared ancestry and ongoing gene flow, most notably unidirectional northward migration out of the SFE. Furthermore, we detected signatures of local adaptation within the Fraser River and the Skeena River estuaries. Taken together, our results identify broad patterns of genetic diversity in longfin smelt shaped by co-ancestry, unidirectional migration and local adaptation. Results also suggest that the SFE population is genetically distinct from northernmost populations and an important source for maintaining nearby populations.Publication Open Access Ecological specialization promotes diversity and diversification in the Eastern Mediterranean genus Ricotia (Brassicaceae)(Wiley, 2021) Özüdoğru, B.; Karacaoğlu, Ç.; Akaydı,n G.; Erik, S.; Mummenhoff, K.; Department of Molecular Biology and Genetics; Sağlam, İsmail Kudret; Faculty Member; Department of Molecular Biology and Genetics; College of Sciences; 168783Despite its amazing biodiversity, the Eastern Mediterranean remains a highly understudied region when compared with the Western Mediterranean, restricting our understanding of diversity across the entire Mediterranean. Here we use a combination of molecular markers and presence/absence data from all species of the Eastern Mediterranean genus Ricotia collected across its full geographic range to determine historical, ecological, and evolutionary factors responsible for lineage-specific diversification in the Eastern Mediterranean. Network analysis based on molecular data revealed a high genetic structure within all lineages, and phylogenetic reconstructions based on the multispecies coalescent showed that within-lineage diversification corresponded to the onset of the Mediterranean climate. Reconstruction of ancestral histories indicates that the genus originated within Anatolia and spread across the Eastern Mediterranean and Levant using the Taurus mountains. Ecological niche models suggest that local populations did not go through any major distributional shifts and have persisted in present-day habitats since the Last Glacial Maximum. Furthermore, niche differentiation tests revealed significant differences between closely related species and showed the main variables predicting species limits to be different for each species. Our results give crucial information on the patterns and processes shaping diversity in the Eastern Mediterranean and show the main factors promoting diversification to be local environmental dynamics and ecological specialization and not large-scale latitudinal movements, as often reported for southern Europe. By determining local and regional patterns of diversification in an Eastern Mediterranean genus, we further our understanding of the major trends influencing plant diversity in the Mediterranean basin as a whole.Publication Open Access Broad- and fine-scale structure across the distribution of the relict dace (Relictus solitarius) in the Great Basin desert, USA(Wiley, 2022) Finger, Amanda J.; Benjamin, Alyssa; Crookshanks, Chris; Campbell, Matthew A.; Department of Molecular Biology and Genetics; Sağlam, İsmail Kudret; Faculty Member; Department of Molecular Biology and Genetics; College of Sciences; 168783The Relict Dace is a small cyprinid and the only species in its genus, Relictus. It is naturally distributed in four drainage basins of central Nevada - Butte Valley, Ruby Valley, Steptoe Valley, and Goshute Valley. The species has experienced periods of isolation and connection within these four basins since the late Pliocene, with the last 100 years characterized by anthropogenic disturbance. To better inform conservation actions, we investigated range-wide and intra-basin genetic structure and diversity and conducted F-st outlier tests using RAD-sequencing. We found high levels of genetic structure and four main lineages on a broad scale corresponding primarily to geography, and on a very fine scale (<1 km) within drainage basins. Signatures of selection in the form of outlier loci were documented in multiple locations across the range. Our results provide baseline data for conservation efforts and highlight the degree of fine-scale genetic structuring that may be present in fishes of the Great Basin that are now restricted to small, isolated habitats-particularly wetland complexes. We caution against assuming that geographic distance is a proxy for genetic similarity in Great Basin fishes, encourage thorough genetic sampling, and note that broad-scale genetic surveys can overlook fine-scale genetic structure.