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Carabajal Paladino, Leonela Z.. 2011 Tesis Doctoral Genética y citogenética de la determinación del sexo en Diachasmimorpha longicaudata (Hymenoptera, Braconidae) Carabajal Paladino, Leonela Z. 2011 Este documento forma parte de la colección de tesis doctorales y de maestría de la Biblioteca Central Dr. Luis Federico Leloir, disponible en digital.bl.fcen.uba.ar. Su utilización debe ser acompañada por la cita bibliográfica con reconocimiento de la fuente. This document is part of the doctoral theses collection of the Central Library Dr. Luis Federico Leloir, available in digital.bl.fcen.uba.ar. It should be used accompanied by the corresponding citation acknowledging the source. Cita tipo APA: Carabajal Paladino, Leonela Z.. (2011). Genética y citogenética de la determinación del sexo en Diachasmimorpha longicaudata (Hymenoptera, Braconidae). Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Cita tipo Chicago: Carabajal Paladino, Leonela Z.. "Genética y citogenética de la determinación del sexo en Diachasmimorpha longicaudata (Hymenoptera, Braconidae)". Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. 2011. Dirección: Biblioteca Central Dr. Luis F. Leloir, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Contacto: [email protected] Intendente Güiraldes 2160 - C1428EGA - Tel. (++54 +11) 4789-9293 UNIVERSIDAD DE BUENOS AIRES Facultad de Ciencias Exactas y Naturales GENÉTICA Y CITOGENÉTICA DE LA DETERMINACIÓN DEL SEXO EN Diachasmimorpha longicaudata (HYMENOPTERA, BRACONIDAE) Tesis presentada para optar al título de Doctor de la Universidad de Buenos Aires en el área: CIENCIAS BIOLÓGICAS Leonela Z. Carabajal Paladino Directores de Tesis: Dra. Alba G. Papeschi Dr. Jorge L. Cladera Dra. María José Bressa Consejero de Estudios: Dra. María Isabel Remis Lugar de trabajo: Laboratorio de Genética de Insectos de Importancia Económica, Istituto de Geétia Eald A. Faet, INTA, Castela. Buenos Aires, 2011 LZ Carabajal Paladino – Tesis Doctoral Resumen GENÉTICA Y CITOGENÉTICA DE LA DETERMINACIÓN DEL SEXO EN Diachasmimorpha longicaudata (HYMENOPTERA, BRACONIDAE) El parasitoide bracónido Diachasmimorpha longicaudata es ampliamente utilizado como controlador biológico de moscas de los frutos; sin embargo, es escaso el conocimiento disponible sobre su genética. A fin de aportar información y mejorar su cría masiva, se estudió su sistema de determinación del sexo mediante la realización de cruzamientos de alta y baja endogamia, utilizando herramientas de citogenética para determinar el nivel de ploidía de la descendencia. Asimismo, se analizó su espermatogénesis y su cariotipo en detalle, realizando aportes a la Teoría de Interacción Mínima, desarrollada para el estudio de la evolución del cariotipo en Hymenoptera. En este parasitoide el sexo se determina por haplodiploidía (machos haploides, hembras diploides), pero en condiciones de alta endogamia ocurre un sesgo significativo de la proporción de sexos hacia machos, debido a la generación de machos diploides. El sexo estaría determinado por el estado de un promedio de tres loci no ligados. Los individuos homocigotas para los loci sexuales se desarrollan en machos diploides. Esta información permitirá mejorar los protocolos de cría masiva de la especie, tratando de minimizar el nivel de endogamia a fin de evitar un incremento en la producción de machos. El estudio citogenético permitió corroborar el número cromosómico descripto previamente. Se analizó la cantidad, composición y distribución de la heterocromatina constitutiva, se mapearon los clusters de genes ribosomales y se determinó la cantidad de clusters activos. La información obtenida permitió aportar más evidencias a favor de la Teoría de Interacción Mínima. Palabras clave: Diachasmimorpha longicaudata, determinación del sexo, haplodiploidía, citogenética, Teoría de Interacción Mínima. i LZ Carabajal Paladino – Tesis Doctoral Abstract GENETICS AND CYTOGENETICS OF SEX DETERMINATION IN Diachasmimorpha longicaudata (HYMENOPTERA, BRACONIDAE) Diachasmimorpha longicaudata is a braconid parasitoid widely used as biological control agent against fruit flies. In spite of its importance, little is known about its genetics. Different aspects were studied in order to provide more information and to optimize its massive production. Its sex determination system was analyzed using inbred and outbred crosses, and cytogenetic tools to analyze the ploidy level of the descendants. Also its spermatogenesis and karyotype were analyzed in detail, contributing to the Minimum Interaction Theory proposed for the study of karyotype evolution in Hymenoptera. Sex is determined by haplodiploidy (males are haploid, females are diploid), but under inbreeding a significant bias towards male progeny is observed due to the generation of diploid males. Sex is presumably determined by a mean of three independent loci. Homozigotes for the sex loci develop into diploid males. In order to avoid an increment in male production, this information would be useful to improve the protocols of massive production of this species, regarding to minimizing the inbreeding levels. The cytogenetic study allowed the corroboration of the chromosome number of the species. The amount, composition and distribution of constitutive heterochromatin were analyzed. The ribosomal gene clusters were located and the quantity of active sites was determined. The obtained information gave more evidence in favor of the Minimum Interaction Theory. Keywords: Diachasmimorpha longicaudata, sex determination, haplodiploidy, cytogenetic, Minimum Interaction Theory. ii LZ Carabajal Paladino – Tesis Doctoral Índice Índice Página Agradecimientos ................................................................................................................... 1 Dedicatoria ........................................................................................................................... 2 Introducción General Características biológicas del orden Hymenoptera ...................................................... 4 Importancia agroeconómica del orden Hymenoptera.................................................. 5 Biología de Diachasmimorpha longicaudata (Ashmead) (Hymenoptera, Braconidae) ......................................................................................................................... 6 Importancia agroeconómica de Diachasmimorpha longicaudata (Ashmead) (Hymenoptera, Braconidae) .................................................................................................. 8 Relevancia del estudio genético y citogenético de Diachasmimorpha longicaudata (Ashmead) (Hymenoptera, Braconidae) ........................................................... 9 Determinación del sexo ¿Qué es la determinación del sexo? ........................................................................... 12 Mecanismos de determinación del sexo en insectos .................................................. 12 Mecanismos de determinación del sexo en Hymenoptera .......................................... 14 Mecanismo de determinación del sexo por alelos complementarios en Hymenoptera ...................................................................................................................... 17 Experimentos para el estudio del modelo de determinación del sexo por alelos complementarios ....................................................................................................... 20 Antecedentes citogenéticos en Hymenoptera Generalidades citogenéticas ...................................................................................... 22 Número, morfología y tamaño cromosómico ............................................................. 23 Cantidad y composición de la heterocromatina constitutiva ....................................... 26 Cantidad y distribución de las regiones organizadoras nucleolares (NORs) ................. 28 Comportamiento meiótico: oogénesis y espermatogénesis ........................................ 29 Reordenamientos cromosómicos ............................................................................... 31 Evolución del cariotipo ............................................................................................... 32 Antecedentes sobre la citogenética de Diachasmimorpha longicaudata..................... 32 Objetivos Objetivos ................................................................................................................... 35 Materiales y Métodos Material experimental................................................................................................ 37 ENSAYO 1: Estudio de la proporción de sexos secundaria y de la tasa de mortalidad en líneas de alta endogamia, generadas a partir del cruzamiento de una hembra virgen y su hijo ................................................................................................. 37 ENSAYO 1.1 Obtención de individuos vírgenes.................................................. 37 ENSAYO 1.2 Establecimiento de las líneas ......................................................... 37 ENSAYO 1.3 Controles exogámicos ................................................................... 38 ENSAYO 1.4 Análisis estadístico ........................................................................ 38 ENSAYO 2: Verificación de la existencia de machos diploides mediante recuento cromosómico en hijos descendientes de cruzamientos madre por hijo ................. 39 ENSAYO 2.1 Establecimiento de los cruzamientos............................................. 39 iii
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