[{"file":[{"file_size":1986078,"file_id":"22588","checksum":"c29880dd71fcc37f23ac6e2843066ede","access_level":"open_access","success":1,"relation":"main_file","file_name":"Aleksa_Spasic_Thesis_final.pdf","content_type":"application/pdf","date_updated":"2026-07-27T13:00:07Z","creator":"aspasic","date_created":"2026-07-27T13:00:07Z"},{"file_name":"Thesis_final.docx","relation":"source_file","creator":"aspasic","date_updated":"2026-07-27T13:07:23Z","date_created":"2026-07-27T13:00:22Z","content_type":"application/vnd.openxmlformats-officedocument.wordprocessingml.document","file_size":1868853,"file_id":"22589","access_level":"closed","checksum":"4ebe3bd2d833d913c0756343cca5e5f0"}],"doi_confirm":"1","status":"public","year":"2026","file_date_updated":"2026-07-27T13:07:23Z","has_accepted_license":"1","page":"32","_id":"22399","article_processing_charge":"No","alternative_title":["ISTA Master’s Thesis"],"department":[{"_id":"GradSch"},{"_id":"GaTk"},{"_id":"CaGu"}],"title":"Studying the evolutionary systems biology of the lac operon","abstract":[{"text":"Gaining an understanding of how biological regulation evolves is a fundamental research \r\nquestion in both evolutionary biology and molecular genetics. In order to gain more insight \r\ninto this topic, we focus on studying the simple gene regulatory system of the lac operon in \r\nE. coli. We show that simple population genetic models can shed light on evolution \r\nexperiments and that this combined approach of modelling the experimental system gives \r\ninsight to better understand the causes of evolutionary change in the experiment. We also \r\nstudy the natural diversity in the lac operon from 308 publicly available E. coli genomes that \r\ncome from various host species and different regions of the world. Evidence that selection is \r\ngenerally maintaining the function of the lac operon across the sample regardless of host \r\nspecies is provided and we show that different protein coding genes in the operon are under \r\ndifferent selective constraints on protein sequence preservation. A similar frameshift \r\nmutation found in experimental evolution studies is shown to be present in the sample we \r\nanalyzed, indicating that selectively relevant variants in evolution experiments are also \r\npresent in natural populations. We show that there is no simple phylogenetic relationship \r\nbetween host species, geographical location and the lac operon sequence. Finally, we argue \r\nthat a combined approach of comparative genomics, experimental evolution and theoretical \r\nmodelling contributes to a more complete understanding of molecular evolution. ","lang":"eng"}],"type":"dissertation","author":[{"id":"ecee9d38-4040-11ef-8843-b941efb445d6","first_name":"Aleksa","full_name":"Spasić, Aleksa","last_name":"Spasić"}],"oa":1,"ddc":["576"],"month":"07","corr_author":"1","degree_awarded":"MS","doi":"10.15479/AT-ISTA-22399","OA_place":"publisher","supervisor":[{"orcid":"0000-0001-6220-2052","id":"47F8433E-F248-11E8-B48F-1D18A9856A87","first_name":"Calin C","last_name":"Guet","full_name":"Guet, Calin C"},{"last_name":"Tkačik","full_name":"Tkačik, Gašper","first_name":"Gašper","id":"3D494DCA-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-6699-1455"}],"date_published":"2026-07-27T00:00:00Z","date_updated":"2026-07-31T10:52:08Z","oa_version":"Published Version","publication_status":"published","publisher":"Institute of Science and Technology Austria","day":"27","language":[{"iso":"eng"}],"publication_identifier":{"issn":["2791-4585"]},"citation":{"mla":"Spasić, Aleksa. <i>Studying the Evolutionary Systems Biology of the Lac Operon</i>. Institute of Science and Technology Austria, 2026, doi:<a href=\"https://doi.org/10.15479/AT-ISTA-22399\">10.15479/AT-ISTA-22399</a>.","apa":"Spasić, A. (2026). <i>Studying the evolutionary systems biology of the lac operon</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/AT-ISTA-22399\">https://doi.org/10.15479/AT-ISTA-22399</a>","short":"A. Spasić, Studying the Evolutionary Systems Biology of the Lac Operon, Institute of Science and Technology Austria, 2026.","ama":"Spasić A. Studying the evolutionary systems biology of the lac operon. 2026. doi:<a href=\"https://doi.org/10.15479/AT-ISTA-22399\">10.15479/AT-ISTA-22399</a>","ista":"Spasić A. 2026. Studying the evolutionary systems biology of the lac operon. Institute of Science and Technology Austria.","chicago":"Spasić, Aleksa. “Studying the Evolutionary Systems Biology of the Lac Operon.” Institute of Science and Technology Austria, 2026. <a href=\"https://doi.org/10.15479/AT-ISTA-22399\">https://doi.org/10.15479/AT-ISTA-22399</a>.","ieee":"A. Spasić, “Studying the evolutionary systems biology of the lac operon,” Institute of Science and Technology Austria, 2026."},"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","das_tickbox":"0","date_created":"2026-07-25T13:08:32Z"}]