{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/108725"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/108725","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Comparative antifreeze trait analyses of Antarctic and temperate sister species pairs shed light on tempo of adaptive trait loss under relaxed selection","abstract":"Antarctic notothenioid fishes endemic to the ice-laden, freezing (-1.9°C) Southern Ocean survive by having evolved antifreeze glycoproteins (AFGP). Over evolutionary time several lineages have escaped the isolated frigid Southern Ocean to north of the Antarctic Polar Front and successfully colonized temperate sub-Antarctic waters. This study investigates the predicted reduction or loss of the prior adaptive AFGP trait in select secondarily temperate notothenioid species when selective pressure no longer exists. The magnitude of the change in AFGP trait expression could inform on the evolutionary history of these species since the AFGP gene evolved only once in notothenioids. We determined the evolutionary status of the AFGP trait in the South American notothenioid Harpagifer bispinis and compared it with its Antarctic sister species Harpagifer antarcticus at the genotypic and phenotypic levels. We found the AFGP trait persists at considerable levels in H. bispinis. AFGP coding sequences remained in its DNA and are transcribed and expressed into functional AFGP proteins. We contrasted this AFGP trait status with another sister notothenioid species pair, the S. American icefish Champsocephalus esox and its Antarctic sister C. gunnari. C. esox co-occurs geographically with H. bispinis, and while AFGP coding sequences also persist in its genome, they are not transcribed or expressed into protein. We constructed a time calibrated Bayesian inferred phylogeny and estimated similar divergence times of H. bispinis/H. antarcticus and C. esox/C. gunnari. Thus, the disparate tempo of AFGP trait change in these two species pairs indicates that alteration of a prior adaptive trait must involve other factors in addition to time in the absence of the apparent selective modality.","abstract_html":"Antarctic notothenioid fishes endemic to the ice-laden, freezing (-1.9°C) Southern Ocean survive by having evolved antifreeze glycoproteins (AFGP). Over evolutionary time several lineages have escaped the isolated frigid Southern Ocean to north of the Antarctic Polar Front and successfully colonized temperate sub-Antarctic waters. This study investigates the predicted reduction or loss of the prior adaptive AFGP trait in select secondarily temperate notothenioid species when selective pressure no longer exists. The magnitude of the change in AFGP trait expression could inform on the evolutionary history of these species since the AFGP gene evolved only once in notothenioids. We determined the evolutionary status of the AFGP trait in the South American notothenioid Harpagifer bispinis and compared it with its Antarctic sister species Harpagifer antarcticus at the genotypic and phenotypic levels. We found the AFGP trait persists at considerable levels in H. bispinis. AFGP coding sequences remained in its DNA and are transcribed and expressed into functional AFGP proteins. We contrasted this AFGP trait status with another sister notothenioid species pair, the S. American icefish Champsocephalus esox and its Antarctic sister C. gunnari. C. esox co-occurs geographically with H. bispinis, and while AFGP coding sequences also persist in its genome, they are not transcribed or expressed into protein. We constructed a time calibrated Bayesian inferred phylogeny and estimated similar divergence times of H. bispinis/H. antarcticus and C. esox/C. gunnari. Thus, the disparate tempo of AFGP trait change in these two species pairs indicates that alteration of a prior adaptive trait must involve other factors in addition to time in the absence of the apparent selective modality.","abstract_has_math":false,"creators":["Wilson, Loralee"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Biology","degree_department":null,"school":null,"contributors":["Cheng-DeVries, Chi-Hing Christina","Fuller, Becky","Catchen, Julian","Tan, Milton"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-10-07T22:50:07Z","date_published":"2020-10-07T22:50:07Z","updated_at":"2026-07-22T22:24:48Z","subjects":["notothenioid","antifreeze glycoprotein","Antarctic","secondarily temperate","relaxed selection","Harpagifer","Champsocephalus"],"languages":["en"],"rights":["Copyright 2020 Loralee Wilson"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/108725","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Cheng-DeVries, Chi-Hing Christina","Fuller, Becky","Catchen, Julian","Tan, Milton"]},{"key":"dc:creator","label":"Author","values":["Wilson, Loralee"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-10-07T22:50:07Z","2022-10-07T22:50:13Z","2020-07-21","2020-08"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["notothenioid","antifreeze glycoprotein","Antarctic","secondarily temperate","relaxed selection","Harpagifer","Champsocephalus"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2020 Loralee Wilson"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/108725"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Antarctic notothenioid fishes endemic to the ice-laden, freezing (-1.9°C) Southern Ocean survive by having evolved antifreeze glycoproteins (AFGP). Over evolutionary time several lineages have escaped the isolated frigid Southern Ocean to north of the Antarctic Polar Front and successfully colonized temperate sub-Antarctic waters. This study investigates the predicted reduction or loss of the prior adaptive AFGP trait in select secondarily temperate notothenioid species when selective pressure no longer exists. The magnitude of the change in AFGP trait expression could inform on the evolutionary history of these species since the AFGP gene evolved only once in notothenioids. We determined the evolutionary status of the AFGP trait in the South American notothenioid Harpagifer bispinis and compared it with its Antarctic sister species Harpagifer antarcticus at the genotypic and phenotypic levels. We found the AFGP trait persists at considerable levels in H. bispinis. AFGP coding sequences remained in its DNA and are transcribed and expressed into functional AFGP proteins. We contrasted this AFGP trait status with another sister notothenioid species pair, the S. American icefish Champsocephalus esox and its Antarctic sister C. gunnari. C. esox co-occurs geographically with H. bispinis, and while AFGP coding sequences also persist in its genome, they are not transcribed or expressed into protein. We constructed a time calibrated Bayesian inferred phylogeny and estimated similar divergence times of H. bispinis/H. antarcticus and C. esox/C. gunnari. Thus, the disparate tempo of AFGP trait change in these two species pairs indicates that alteration of a prior adaptive trait must involve other factors in addition to time in the absence of the apparent selective modality.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-08-01","The student, Loralee Wilson, accepted the attached license on 2020-07-20 at 19:24.","The student, Loralee Wilson, submitted this Thesis for approval on 2020-07-20 at 19:59.","This Thesis was approved for publication on 2020-07-21 at 08:01.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15703 on 2020-10-02 at 15:52:12","Made available in DSpace on 2020-10-07T22:50:07Z (GMT). No. of bitstreams: 2 WILSON-THESIS-2020.pdf: 2988344 bytes, checksum: b4c504f9b64430cd3273a83ae5ccd470 (MD5) LICENSE.txt: 4211 bytes, checksum: cfb12119f57ae3a3c7277cde5b0754f5 (MD5) Previous issue date: 2020-07-21","Embargo set by: Seth Robbins for item 116354 Lift date: 2022-10-07T22:50:13Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Comparative antifreeze trait analyses of Antarctic and temperate sister species pairs shed light on tempo of adaptive trait loss under relaxed selection"]}]}],"canonical_facts":{"dc:contributor":["Cheng-DeVries, Chi-Hing Christina","Fuller, Becky","Catchen, Julian","Tan, Milton"],"dc:creator":["Wilson, Loralee"],"dc:date":["2020-10-07T22:50:07Z","2022-10-07T22:50:13Z","2020-07-21","2020-08"],"dc:description":["Antarctic notothenioid fishes endemic to the ice-laden, freezing (-1.9°C) Southern Ocean survive by having evolved antifreeze glycoproteins (AFGP). Over evolutionary time several lineages have escaped the isolated frigid Southern Ocean to north of the Antarctic Polar Front and successfully colonized temperate sub-Antarctic waters. This study investigates the predicted reduction or loss of the prior adaptive AFGP trait in select secondarily temperate notothenioid species when selective pressure no longer exists. The magnitude of the change in AFGP trait expression could inform on the evolutionary history of these species since the AFGP gene evolved only once in notothenioids. We determined the evolutionary status of the AFGP trait in the South American notothenioid Harpagifer bispinis and compared it with its Antarctic sister species Harpagifer antarcticus at the genotypic and phenotypic levels. We found the AFGP trait persists at considerable levels in H. bispinis. AFGP coding sequences remained in its DNA and are transcribed and expressed into functional AFGP proteins. We contrasted this AFGP trait status with another sister notothenioid species pair, the S. American icefish Champsocephalus esox and its Antarctic sister C. gunnari. C. esox co-occurs geographically with H. bispinis, and while AFGP coding sequences also persist in its genome, they are not transcribed or expressed into protein. We constructed a time calibrated Bayesian inferred phylogeny and estimated similar divergence times of H. bispinis/H. antarcticus and C. esox/C. gunnari. Thus, the disparate tempo of AFGP trait change in these two species pairs indicates that alteration of a prior adaptive trait must involve other factors in addition to time in the absence of the apparent selective modality.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-08-01","The student, Loralee Wilson, accepted the attached license on 2020-07-20 at 19:24.","The student, Loralee Wilson, submitted this Thesis for approval on 2020-07-20 at 19:59.","This Thesis was approved for publication on 2020-07-21 at 08:01.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15703 on 2020-10-02 at 15:52:12","Made available in DSpace on 2020-10-07T22:50:07Z (GMT). No. of bitstreams: 2 WILSON-THESIS-2020.pdf: 2988344 bytes, checksum: b4c504f9b64430cd3273a83ae5ccd470 (MD5) LICENSE.txt: 4211 bytes, checksum: cfb12119f57ae3a3c7277cde5b0754f5 (MD5) Previous issue date: 2020-07-21","Embargo set by: Seth Robbins for item 116354 Lift date: 2022-10-07T22:50:13Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/108725"],"dc:language":["en"],"dc:rights":["Copyright 2020 Loralee Wilson"],"dc:subject":["notothenioid","antifreeze glycoprotein","Antarctic","secondarily temperate","relaxed selection","Harpagifer","Champsocephalus"],"dc:title":["Comparative antifreeze trait analyses of Antarctic and temperate sister species pairs shed light on tempo of adaptive trait loss under relaxed selection"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:48Z"}