El establecimiento de clinas latitudinales para caracteres del polimorfismo de inversión y la morfología en poblaciones americanas de Drosophila subobscura, paralelas a las existentes en la región paleártica, sugieren la adaptación a condiciones ambientales análogas. Un factor climático que cambia con la latitud es la temperatura, por lo tanto este podría ser el agente causal de la formación de las clinas latitudinales. Por lo tanto, el objetivo principal de este trabajo fue estudiar los efectos de diferentes regimenes térmicos en el polimorfismo cromosómico de inversión, así como la variación en tamaño y forma del ala en Drosophila subobscura. Así, tres poblaciones replicadas de D subobscura derivadas de un stock endogámico de Puerto Montt (Chile) fueron mantenidas cada una a tres regimenes térmicos diferentes (correspondiendo a condiciones de frió la temperatura de 13°C, de óptimo a 18°C y de cálido a 22°C) por 2 años. Los resultados indican que el polimorfismo de inversión ha respondido rápido y consistentemente a la temperatura, Sin embargo, los cambios observados en las frecuencias de muchos ordenamientos cromosómicos no son consistentes con las predicciones basadas en las clinas latitudinales observadas en las poblaciones europeas de los últimos 30 años. Además, hay una rápida y consistente evolución termal de la forma del ala (pero no en tamaño), y las tasas de divergencia para forma del ala son tan rápidas o incluso mas rápidas que estas previamente estimadas para tamaño del ala a una escala continental. La conclusión es que la temperatura no es el agente causal de las clinas latitudinales.Por otro lado, muchas propiedades de los organismos muestran gran fuerza genética contra las perturbaciones ambientales. Los términos canalización y estabilidad del desarrollo fueron propuesto originalmente para describir la habilidad de un organismo para resistir las perturbaciones y para producir un posible fenotipo blanco a pesar del ruido de desarrollo aleatorio. En la segunda parte de este trabajo, se analizaron los efectos de la variación genética clinal (polimorfismo de inversión) en la asimetría del ala por los métodos aplicados de morfometría geométrica en el contexto de la genética cuantitativa, usando líneas isocromosómicas de Drosophila subobscura. En los análisis de tamaño en general, la estabilidad de desarrollo fue positivamente correlacionada con los niveles de heterocigosidad y el desarrollo a la temperatura optima. En los análisis de forma, las comparaciones totales por correlación de matrices indican que los niveles de variación inter o intra individual fueron pobremente correlacionados, un resultado que tiene soporte también, cuando se comparan los vectores de patrones descritos para la variación de posición de landmarks. La falta de similaridad fue básicamente debida a las discrepancias entre los componentes genético y ambiental de la variación interindividual. Los análisis han mostrado también una presencia baja de variación genética para la asimetría direccional. Finalmente, los resultados soportan fuertemente que la canalización ambiental y la estabilidad de desarrollo comparten mecanismos reguladores subyacentes, pero la canalización ambiental y genética no son funcionalmente lo mismo. Una explicación posible para esta falta de asociación es que la variación de la forma del ala en las poblaciones naturales de Drosophila está indirectamente relacionada con el fitness individual. / The establishment in American populations of Drosophila subobscura of parallel latitudinal clines, in the polymorphism of inversion and morphologic characters, to the existing ones in the paleartica region suggests adaptation to analogous environmental conditions. A climatic factor that changes with the latitude is temperature, maybe it's the causal agent in shaping of latitudinal clines. Therefore, the aim of this work was to study the effects of different thermal regimes on chromosomal inversion polymorphism, as well as variation in wing size and shape in Drosophila subobscura. Thus, three replicated populations of D. subobscura derived from an outbreed stock of Puerto Montt (Chile) were each kept at three different thermal regimes (corresponding to cold a temperature of 13°C, to optimal to 18°C and to warm to 22°C conditions) for 2 years.The results indicate that the polymorphism of inversion has responded fast and consistently to the temperature. However, the changes observed in the frequencies of many chromosomal arrangements are not consistent with the predictions based on the latitudinal clines observed in European populations in the last 30 years. In addition, there is a rapid and consistent thermal evolution of wing shape (but not size), and rates of genetic divergence for wing shape are as fast or even faster than those previously estimated for wing size to a continental scale. The conclusion is that the temperature isn't the causal agent of latitudinal clines.On the other hand, many properties of the organism show great robustness against genetic and environmental perturbation. The terms canalization and developmental stability were originally proposed to describe the ability of an organism to resist perturbations and to produce a predictable target phenotype regardless of random developmental noise. In the second part of this work, we have analyzed the effects of clinal genetic variation (inversion polymorphism) on wing asymmetry by applying the methods of geometric morphometrics in the context of quantitative genetics using isochromosomal lines of Drosophila subobscura. For the analysis of overall size, developmental stability was positive correlated with levels of heterozigosity and development at the optimal temperature. For analyses of shape, the overall comparisons by matrix correlations indicate that inter and intraindividual variation levels were poorly correlated, a result also supported when comparing the vectors describing patterns of variation of landmark position. The lack of similarity was basically due to discrepancy between the genetic and environmental components of the interindividual variation. The analyses have also underscored the presence of genetic variation for directional asymmetry. Finally, the results strongly support that environmental canalization and developmental stability share underlying regulatory mechanism, but environmental and genetic canalization are not functionally the same, maybe because the natural wing shape variation in Drosophila populations is loosely related to individual fitness.

Made available in DSpace on 2016-04-28T15:01:30Z (GMT). No. of bitstreams: 1 2006-Marcio de Araujo Silva.pdf: 1021649 bytes, checksum: 0b981908af67bec8e46455a6b9a080ca (MD5) Previous issue date: 2006-04-25 / Morphological variation for the anchovy Lycengraulis grossidens (Agassiz, 1829) in 14 sites along the Brazilian coast (Par? to Rio Grande do Sul) were described to quantify the intraspecific heterogeneity, and to test the hypothesis that seeking for adaptability to different areas results in differentiated patterns that characterize isolated populations. A total of 210 individuals from collection from Museums plus donations, were examined, from which 18 morphometric and 5 meristic characters were taken. Three groups (populations) were formed based on morphometrics and one additional group (4 groups) by meristic characters, indicating the presence of 4 populations along the Brazilian coast. Population I, from the Par? coast, inhabit an area of major influence of the Amazon river, showing waters of low salinity and high temperature. Population II, from Cear? to Esp?rito Santo State, has a wider distribution, showing overall similar mophological characters to population I, indicating gene flow between these two populations. Population III comprises fishes between Rio de Janeiro and S?o Paulo States, and show a transition zone with population II well evidenced in the north of Rio de Janeiro, suggesting to be an hybridizing area. Population IV, from Santa Catarina to Rio Grande do Sul, showed the highest number and largest sized gillrakers, being the most morphologically differentiated group. Fishes from low latitudes showed higher body width, head length, cheek length, maxilla length, mouth length and peduncle width compared with fishes from high latitude. Additionally, specimens from Santa Catarina and Rio Grande do Sul showed anal and dorsal fins located in more posterior body position, while anal fin base was larger for specimens form Rio de Janeiro and S?o Paulo, indicating that fishes from this former areas (SC and RS) have higher capacity to move in higher speed when compared with fishes from this latter area (RJ e SP). Concerning to meristics characters, there is an increased number of gillrakers from lower to higher latitudes, coinciding with the expectation of somites addition to occur faster in acceleration condition than under retarding condition, but finish abruptly, resulting in lower number of meristics element in higher temperatures. Several zoogeographic pattern has been described for the Brazilian coast, with the Antillean Province situated at north of Cabo Frio (23oS), a transition area between Cabo Frio (23oS) and the surrounds of Cabo de Santa Marta Grande (28?-30?S), and the Argentine Province up to 35?S, with this division closely coinciding with L.grossidens populations distribution in this study, except for the Para coast, where we recognize a differentiated group. / Varia??es morfo-meristicas da manjuba Lycengraulis grossidens (Agassiz, 1829) em 14 localidades da costa brasileira (Par? ao Rio Grande do Sul) foram descritas com o objetivo de quantificar a heterogeneidade intra-espec?fica, visando testar a hip?tese de que a adaptabilidade em ?reas diferentes resulta em padr?es diferenciados que caracterizem diferentes popula??es. Foram examinados 210 indiv?duos oriundos de cole??es depositadas em Museus e complementadas com doa??es, dos quais foram tomados 18 caracteres morfom?tricos e 5 mer?sticos. Tr?s grupos (popula??es) foram formados com base nos caracteres morfom?tricos e um grupo adicional (4 grupos) por caracteres mer?sticos, indicando a presen?a de 4 popula??es ao longo da costa brasileira. A popula??o I, do litoral do Par?, habita uma ?rea sob grande influ?ncia do rio Amazonas, com ?guas de baixa salinidade e alta temperatura. A popula??o II, que se estende do Cear? ao Esp?rito Santo, ? a de distribui??o mais ampla, apresentando em geral caracteres morfol?gicos semelhantes aos da popula??o I, o que poderia indicar a exist?ncia de fluxo g?nico entre as mesmas. A popula??o III compreende os peixes distribu?dos entre Rio de Janeiro e S?o Paulo, e apresenta uma zona de transi??o com a popula??o II bastante evidenciada no norte do Rio de Janeiro, aparentando ser esta ?ltima uma ?rea de hibridiza??o. A popula??o IV, de Santa Catarina e Rio Grande do Sul, apresenta como caracter?sticas mais marcantes o n?mero e o comprimento dos rastros branquiais, sendo o grupo morfologicamente mais diferenciado. Peixes de baixas latitudes apresentaram maior altura do corpo, comprimento da cabe?a, comprimento da face, comprimento da maxila, comprimento da boca e altura do ped?nculo caudal, comparados aos peixes de altas latitudes. Adicionalmente, os esp?cimes da popula??o IV apresentaram nadadeira anal e dorsal localizadas em posi??o mais posterior do corpo, enquanto a base da nadadeira anal foi maior em esp?cimes do Rio de Janeiro e S?o Paulo, indicando que peixes da popula??o IV possuem maior capacidade de se deslocar em velocidade quando comparados com peixes do Rio de Janeiro e S?o Paulo. Em rela??o aos caracteres mer?sticos verificou-se um aumento do n?mero de rastros branquiais das menores para as maiores latitudes, coincidindo com a expectativa de que a adi??o de somitos ocorre mais rapidamente sob condi??es de acelera??o do que sob condi??es retardantes, mas termina mais abruptamente, resultando em menor n?mero de elementos mer?sticos em temperaturas mais altas. V?rios padr?es zoogeogr?ficos t?m sido sugeridos para a costa brasileira, com a Prov?ncia Antilhana situada ao norte de Cabo Frio (23oS), uma ?rea de transi??o entre Cabo Frio (23oS) e o os arredores Cabo de Santa Marta Grande (28?-30?S), e a Prov?ncia Argentina at? 35?S, com esta divis?o da costa de certo modo, coincidindo com as distribui??es das popula??es de L.grossidens encontradas no presente trabalho, com exce??o da ?rea costeira do Par?, onde reconhecemos um grupo diferenciado.