Two intertidal invertebrate species, M galloprovincialis and Balanus glandula, were collected from seven different bay sites along the Southern California coast to test if environmental contamination is associated with the decrease of genetic diversity at the population level. Collections were made at three relatively pristine \"clean\" sites and four \"impacted\" sites which were exposed to heavy industrial or boating activity and which had previously, been identified as having measurable levels of pollution. The \"Comet\" assay (Single Cell Gel electrophoresis) was performed to measure single-strand DNA breaks in mussels at several of the sites in order to confirm differing impacts of pollution on the animals at the different sites. In this assay, cells in impacted populations with increased DNA damage displayed increased migration from the nuclear region towards the anode during electrophoresis. Genetic diversity at the different sites was assessed by comparing fragment polymorphisms generated from genomic DNA by RAPD-PCR (Randomly Amplified Polymorphic DNA - Polymerase Chain Reaction). All populations exhibited a large amount of genetic diversity and were genetically similar to each other. However, several different measures of diversity indicated that for most primers, the populations of both species from impacted sites had lower genetic diversity compared to populations from clean sites. Individuals at impacted sites were more likely to share the same haplotypes than were those from clean sites. Few bands seen in the clean populations were absent from the impacted populations or vice versa, but a number of bands which were common in the clean site populations were significantly less common in the impacted populations. Together, these results suggest that pollution at the impacted sites may act as a selection force decreasing genetic diversity among the resident invertebrate populations.
","abstract_html":"<p>Two intertidal invertebrate species, <em>M galloprovincialis</em> and <em>Balanus glandula</em>, were collected from seven different bay sites along the Southern California coast to test if environmental contamination is associated with the decrease of genetic diversity at the population level. Collections were made at three relatively pristine "clean" sites and four "impacted" sites which were exposed to heavy industrial or boating activity and which had previously, been identified as having measurable levels of pollution. The "Comet" assay (Single Cell Gel electrophoresis) was performed to measure single-strand DNA breaks in mussels at several of the sites in order to confirm differing impacts of pollution on the animals at the different sites. In this assay, cells in impacted populations with increased DNA damage displayed increased migration from the nuclear region towards the anode during electrophoresis. Genetic diversity at the different sites was assessed by comparing fragment polymorphisms generated from genomic DNA by RAPD-PCR (Randomly Amplified Polymorphic DNA - Polymerase Chain Reaction). All populations exhibited a large amount of genetic diversity and were genetically similar to each other. However, several different measures of diversity indicated that for most primers, the populations of both species from impacted sites had lower genetic diversity compared to populations from clean sites. Individuals at impacted sites were more likely to share the same haplotypes than were those from clean sites. Few bands seen in the clean populations were absent from the impacted populations or vice versa, but a number of bands which were common in the clean site populations were significantly less common in the impacted populations. Together, these results suggest that pollution at the impacted sites may act as a selection force decreasing genetic diversity among the resident invertebrate populations.</p>","abstract_has_math":false,"creators":["Ma, Xiao Li"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation","degree_discipline":"Biology","degree_department":null,"school":null,"contributors":["David L. Cowles","Leonard Brand","Ronald L. Carter","E. Clifford Herrmann","George T. Javor"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1999,"date_issued":"1999-12-01T08:00:00Z","date_published":"1999-12-01T08:00:00Z","updated_at":"2026-07-24T02:53:08Z","subjects":["Marine Biology","Variation (Biology) -- Effect of pollution on -- Southern California Bight (Calif. and Mexico); Mytilus galloprovincialis -- Effect of pollution on; Balanidae -- Effect of pollution on; ntertidal ecology -- Southern California Bight (Calif. and Mexico)."],"languages":["English"],"rights":["This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsrepository.llu.edu/etd/721","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["David L. Cowles","Leonard Brand","Ronald L. Carter","E. Clifford Herrmann","George T. Javor"]},{"key":"dc:creator","label":"Author","values":["Ma, Xiao Li"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Marine Biology","Variation (Biology) -- Effect of pollution on -- Southern California Bight (Calif. and Mexico); Mytilus galloprovincialis -- Effect of pollution on; Balanidae -- Effect of pollution on; ntertidal ecology -- Southern California Bight (Calif. and Mexico)."]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsrepository.llu.edu/etd/721"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Two intertidal invertebrate species, M galloprovincialis and Balanus glandula, were collected from seven different bay sites along the Southern California coast to test if environmental contamination is associated with the decrease of genetic diversity at the population level. Collections were made at three relatively pristine \"clean\" sites and four \"impacted\" sites which were exposed to heavy industrial or boating activity and which had previously, been identified as having measurable levels of pollution. The \"Comet\" assay (Single Cell Gel electrophoresis) was performed to measure single-strand DNA breaks in mussels at several of the sites in order to confirm differing impacts of pollution on the animals at the different sites. In this assay, cells in impacted populations with increased DNA damage displayed increased migration from the nuclear region towards the anode during electrophoresis. Genetic diversity at the different sites was assessed by comparing fragment polymorphisms generated from genomic DNA by RAPD-PCR (Randomly Amplified Polymorphic DNA - Polymerase Chain Reaction). All populations exhibited a large amount of genetic diversity and were genetically similar to each other. However, several different measures of diversity indicated that for most primers, the populations of both species from impacted sites had lower genetic diversity compared to populations from clean sites. Individuals at impacted sites were more likely to share the same haplotypes than were those from clean sites. Few bands seen in the clean populations were absent from the impacted populations or vice versa, but a number of bands which were common in the clean site populations were significantly less common in the impacted populations. Together, these results suggest that pollution at the impacted sites may act as a selection force decreasing genetic diversity among the resident invertebrate populations.
"]},{"key":"dc:title","label":"Title","values":["Effect of Pollution on Genetic Diversity in the Southern California Bight"]}]}],"canonical_facts":{"dc:contributor":["David L. Cowles","Leonard Brand","Ronald L. Carter","E. Clifford Herrmann","George T. Javor"],"dc:creator":["Ma, Xiao Li"],"dc:description.abstract":["Two intertidal invertebrate species, M galloprovincialis and Balanus glandula, were collected from seven different bay sites along the Southern California coast to test if environmental contamination is associated with the decrease of genetic diversity at the population level. Collections were made at three relatively pristine \"clean\" sites and four \"impacted\" sites which were exposed to heavy industrial or boating activity and which had previously, been identified as having measurable levels of pollution. The \"Comet\" assay (Single Cell Gel electrophoresis) was performed to measure single-strand DNA breaks in mussels at several of the sites in order to confirm differing impacts of pollution on the animals at the different sites. In this assay, cells in impacted populations with increased DNA damage displayed increased migration from the nuclear region towards the anode during electrophoresis. Genetic diversity at the different sites was assessed by comparing fragment polymorphisms generated from genomic DNA by RAPD-PCR (Randomly Amplified Polymorphic DNA - Polymerase Chain Reaction). All populations exhibited a large amount of genetic diversity and were genetically similar to each other. However, several different measures of diversity indicated that for most primers, the populations of both species from impacted sites had lower genetic diversity compared to populations from clean sites. Individuals at impacted sites were more likely to share the same haplotypes than were those from clean sites. Few bands seen in the clean populations were absent from the impacted populations or vice versa, but a number of bands which were common in the clean site populations were significantly less common in the impacted populations. Together, these results suggest that pollution at the impacted sites may act as a selection force decreasing genetic diversity among the resident invertebrate populations.
"],"dc:identifier":["https://scholarsrepository.llu.edu/etd/721"],"dc:language":["English"],"dc:rights":["This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights."],"dc:subject":["Marine Biology","Variation (Biology) -- Effect of pollution on -- Southern California Bight (Calif. and Mexico); Mytilus galloprovincialis -- Effect of pollution on; Balanidae -- Effect of pollution on; ntertidal ecology -- Southern California Bight (Calif. and Mexico)."],"dc:title":["Effect of Pollution on Genetic Diversity in the Southern California Bight"],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T02:53:08Z"}