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dc.contributor.advisorSchizas, Nikolaos
dc.contributor.authorRojas, Monica L.
dc.description.abstractEchinoderms display a wide array of life histories, which can have a profound effect in the dispersal potential and population structure of species. The brittle stars Ophiocoma echinata and Amphipholis squamata are commonly found in the shallow waters of the Caribbean Sea. The two species exhibit differing modes of development: O. echinata is a spawning species having asynchronous breeding cycles and A. squamata is a brooding species, viviparous and selffertilizing hermaphrodite. Their overlapping geographic range offers the opportunity to compare their genetic population structure as brooders are expected to exhibit higher population subdivision than spawners. Mitochondrial (16S) and ribosomal nuclear DNA sequences (ITS-1) were recovered from 16 populations of O. echinata and five populations of A. squamata around the Caribbean and Western Atlantic. Results indicate that the spawning O. echinata harbors moderate levels of genetic variability in the 16S gene (163 specimens, 66 haplotypes). There is no significant population structure (16S; FST = 0.00236; P = 0.38319) in this wide geographic area. This pattern is further supported by the ITS-1 gene. A. squamata however, harbors high levels of genetic variability (63 specimens, 45 haplotypes) with two well supported lineages. One of these is a newly discovered lineage of A. squamata around the world. Significant population structure (16S; FST = 0.63867; P = 0.0000) was observed between Puerto Rico and Florida, a result supported by the ITS-1 data. At a finer geographic scale in southwestern Puerto Rico, population differentiation was observed in A. squamata (FST = 0.14845; p<0.01369). These data provide compelling evidence that life history traits influence the connectivity of geographically distant populations. The spawner O. echinata showed no population structure from samples as far as Bermuda, Curaçao, Panama and Belize whereas the brooder A. squamata is potentially a complex of at least 2 cryptic species with partially overlapping geographic distributions.en_US
dc.description.abstractLos echinodermos poseen una amplia variabilidad de historias de vida, lo cual pueden tener un efecto profundo en el potencial de dispersión y estructura poblacional de las especies. Las estrellas quebradizas Ophiocoma echinata y Amphipholis squamata son comúnmente encontradas en aguas someras del mar Caribe. Las dos especies exhiben diferentes modos de desarrollo: O. echinata es una especie que desova y posee ciclos asíncronos y A. squamata es una especie que incuba, vivípara y hermafrodita que se fertiliza a si misma. Debido a que coinciden en su rango geográfico esto ofrece la oportunidad de comparar su estructura poblacional, se espera que la especie que incuba exhiba más alta subdivisión poblacional que la especie que desova. Secuencias de ADN mitocondrial (16S) y ribosomal nuclear (ITS-1) fueron obtenidas de 16 poblaciones de O. echinata y cinco poblaciones de A. squamata alrededor del Caribe y el Atlántico oeste. Los resultados indican que la especie que desova O. echinata posee niveles moderados de variabilidad genética en el gen 16S (163 especímenes, 66 haplotipos). No existe estructura poblacional significativa (16S; FST = 0.00236; P = 0.38319) en esta amplia región geográfica. Este comportamiento es apoyado por el gen ITS-1. Al contrario, A. squamata posee altos niveles de variabilidad genética (63 especímenes, 45 haplotipos) con dos linajes bien soportado. Uno de los linajes es un nuevo reporte para A. squamata alrededor del mundo. Estructura poblacional significativa (16S; FST = 0.63867; P = 0.0000) fue observada entre Puerto Rico y Florida, resultados son soportados con los datos del gen ITS-1. En una escala geográfica fina en el sudoeste de Puerto Rico se observó una diferenciación poblacional en A. squamata (16S; FST = 0.14845; p<0.01369). Estos datos proveen evidencia convincente de que los rasgos de historia de vida influencias las tasas de conectividad de las poblaciones geográficamente. Ophiocoma echinata la especie que desova, no exhibe estructura poblacional incluso muestras tan distantes como Bermuda, Curaçao, Panamá y Belize donde A. squamata la especie incubadora muestra un complejo de por lo menos 2 especies cripticas con una coincidencia parcial en la distribución geográfica.en_US
dc.description.sponsorshipLerner Gray Fellowship in Marine Biology (American Museum of Natural History); Charles Cutress Travel Award; Department of Marine Sciences, University of Puerto Rico at Mayagüez; Puerto Rico Sea Grant Program; Governments of Panamá, Guadeloupe, Curaçao and the Dominican Republic; Natural History Museum of Los Angeles Countyen_US
dc.subjectOphiocoma echinata - Population structure - Caribbean Seaen_US
dc.subjectAmphipholis squamata - Population structure - Caribbean Seaen_US
dc.subjectAmphipholis squamata - DNA sequenceen_US
dc.subjectOphiocoma echinata - DNA sequenceen_US
dc.subject.lcshEchinodermata --Caribbean Sea -- Geneticsen_US
dc.subject.lcshAmphiuridae -- Geneticsen_US
dc.subject.lcshOphiocomidae -- Geneticsen_US
dc.titleGenetic population structure of two species of brittle stars with contrasting life historiesen_US
dc.rights.licenseAll rights reserveden_US
dc.rights.holder(c) 2010 Monica L. Rojasen_US
dc.contributor.committeeYoshioka, Paul
dc.contributor.committeeWeil, Ernesto
dc.contributor.committeeAponte, Nilda
dc.contributor.representativeRamirez, Lillian Sciencesen_US
dc.contributor.collegeCollege of Arts and Sciences - Sciencesen_US
dc.contributor.departmentDepartment of Marine Sciencesen_US

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