Show simple item record

dc.contributor.advisorYoshioka, Paul M.
dc.contributor.authorPrada-Montoya, Carlos A.
dc.date.accessioned2018-12-15T11:47:48Z
dc.date.available2018-12-15T11:47:48Z
dc.date.issued2007-05
dc.identifier.urihttps://hdl.handle.net/20.500.11801/1632
dc.description.abstractClonal marine organisms exhibit high levels of morphological variation. Morphological variation may be a response to environmental factors but also they can be attributed to genetic factors. In this study, we examined the extensive morphological variation observed in the gorgonian Plexaura flexuosa (Lamouroux, 1821), a widely distributed Caribbean octocoral. We quantified differences in morphological traits in natural populations along depth profiles (shallow <5 m and deep >17 m), degree of protection to water motion and sedimentation rates (from inshore, protected and high sedimentation rates to offshore, exposed and lower sediment loads). Also, transplant experiments and genetic analysis were performed to test for possible ecophenotypic and genetic interactions. Significant differences (P<0.001) in 14 morphological traits were found among colonies inhabiting 12 locations comprising seven reefs in southwest Puerto Rico. Results from principal component analysis indicated the presence of two groups based on depth distribution, suggesting the presence of two discrete morphotypes (i.e. shallow type <5 m and deep type >17 m). A discriminant function analysis based on a priori univariate and multivariate analyses (which separated the colonies in morphotypes) correctly classified 93% of the colonies for each environment. Light, water motion and sediment transport co-varied along the depth profiles and they might influence the distribution of the two morphotypes. However, the study was not designed to separate the contribution of each variable. Reaction norms of morphological characters of colonies that were reciprocally transplanted showed gradual significant changes through the 15 months of transplantation. Sclerites of shallow water colonies became larger when transplanted to deeper environments and vice versa, but, neither of the two transplanted groups overlapped with the residents’ morphology. Genetic analysis of mitochondrial and nuclear genes suggested that such discrete morphology and non-overlapping phenotypic plasticity is correlated with the presence of two independent evolutionary lineages distributed non-randomly in shallow and deep environments. The genetic patterns found in the two sympatrically living morphs may have resulted from 1) secondary contact after populations diverged in allopatry and reproductive isolation machinery developed, 2) by divergence with gene flow through ecological specialization in sympatry or 3) by the poorly understood process of hybridization in anthozoan evolution.en_US
dc.description.abstractLos organismos marinos coloniales presentan una gran variedad de formas pese a su dependencia en la reproducción asexual y por ende baja diversidad genética. Esta variedad de formas les permite mantener sus poblaciones y contribuye a su habilidad para adaptarse a nuevos ambientes. En este trabajo, se cuantificó la variabilidad morfológica en poblaciones naturales a través de gradientes ambientales del común y ampliamente distribuido octocoral Plexaura flexuosa (Lamouroux, 1821). Al mismo tiempo, se estimo la contribución genética y ambiental de dichas variaciones morfológicas y su importancia en procesos de adaptación y evolución de la especie. Se encontraron Diferencias significativas (p<0.001) en los 14 caracteres morfológicos estudiados en las 12 poblaciones analizadas, sugiriendo que hay dos morfologías discretas asociadas a la profundidad (i.e. tipo-somero <5m y tipoprofundo> 20m). Diferencias en el movimiento del agua y el transporte de sedimentos en los diferentes lugares de muestreo pueden estar también asociadas a la variación morfológica. Los dos morfotipos fueron correctamente clasificados (93%) en su propio ambiente en el análisis multivariado discriminate basado en los patrones de profundidad. Las normas de reacción de los caracteres morfológicos en las colonias recíprocamente transplantadas mostraron cambios graduales en su tamaño a través del tiempo (15 meses). El tamaño de las espículas de las colonias someras incremento en el tiempo y viceversa, sin embargo nunca se observo un solape con la morfología de las colonias residentes. La distribución discreta de las características morfológicas, así como un patrón rígido de plasticidad fenotípica están altamente relacionados con diferencias genéticas encontradas en el ADN mitocondrial y nuclear. Aun mas, los dos linajes evolutivos no se distribuyen aleatoriamente en los ambientes naturales y posiblemente han desarrollado mecanismos de adaptación a sus correspondientes habitas, consecuentemente disminuyendo su mortalidad en sus óptimos nichos. El patrón genético encontrado en los dos linajes que viven en sympatria pudo haberse debido a: 1) un contacto secundario después de que las dos formas habían divergido y se había desarrollado maquinaria reproductiva independiente, 2) por divergencia en sympatria a través de especialización ecológica o 3) por el pobremente estudiado proceso de hibridación en la evolución de antozoarios.en_US
dc.description.sponsorshipSigma Xi research-in-aid grant; Sea Grant Seed Money; Restoration of Gorgonian populations from the Sea Grant program of the UPRM; Coral Reef Ecosystem Studies from NOAA; NSF-EPSCOR start up fund; Caribbean Coral reef Institute grant; Departments of Biology and Chemistry teaching assistantship' The National Institute of Health; Society for Integrative and Comparative biology; University of Washington; University of Puerto Rico through the Arts and Sciences Divisionen_US
dc.language.isoenen_US
dc.subjectPlexaura flexuosa - Phenotypic plasticity – Reefs – Puerto Ricoen_US
dc.subjectClones (Plants) Variation – Reefs – Puerto Ricoen_US
dc.subjectPlexaura flexuosa - Plasticity (Physiology)en_US
dc.subject.lcshPlexaura flexuosa.en_US
dc.subject.lcshAlcyonaria--Puerto Rico--Morphology.en_US
dc.subject.lcshGorgonacea--Puerto Rico--Morphology.en_US
dc.titlePhenotypic and genetic variability in the octocoral Plexaura flexuosaen_US
dc.typeThesisen_US
dc.rights.licenseAll rights reserveden_US
dc.rights.holder(c) 2007 Carlos Andrés Prada Montoyaen_US
dc.contributor.committeeSchizas, Nikolaos
dc.contributor.committeeWeil, Ernesto
dc.contributor.committeeAponte, Nilda
dc.contributor.representativeAlmodovar, Wanda
thesis.degree.levelM.S.en_US
thesis.degree.disciplineMarine Sciencesen_US
dc.contributor.collegeCollege of Arts and Sciences - Sciencesen_US
dc.contributor.departmentDepartment of Marine Sciencesen_US
dc.description.graduationSemesterSpringen_US
dc.description.graduationYear2007en_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

  • Theses & Dissertations
    Items included under this collection are theses, dissertations, and project reports submitted as a requirement for completing a degree at UPR-Mayagüez.

Show simple item record

All rights reserved
Except where otherwise noted, this item's license is described as All Rights Reserved