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Objetivou-se, principalmente, conhecer a paridade, desenvolvimento ovariano e a razão de sobrevivência dessas populações. As coletas foram realizadas na Fazenda Experimental do Instituto Agronômico de Campinas e em sítio próximo, denominado Barra do Capinzal. Ambos situados no município de Pariquera-Açu, Estado de São Paulo. De maneira concomitante, as capturas foram feitas nos ambientes extradomiciliar e domiciliar, mediante o emprego da isca humana e armadilha tipo Shannon. Focalizou-se o complexo Anopheles albitarsis, populações prováveis A e B, por ocasião do período crepuscular vespertino. As dissecções foram feitas utilizando-se da técnica de Polovodova. Para a avaliação do desenvolvimento folicular, adotou se o critério de Christophers e Mer e o conceito baseado na Escola Clássica. Das 4.170 fêmeas dissecadas, 90,2 por cento foram da população B e 9,8 por cento da população A. Quanto à paridade, o resultado global revelou que o grupo das nulíparas foi predominante, com aproximadamente 70,0 por cento . A uniparidade com aproximadamente 25,0 por cento , a biparidade com aproximadamente 2,5 por cento e o grupo com 3 e 4 dilatações foi inferior a 1,0 por cento . Quanto ao desenvolvimento folicular, a proporção de fêmeas com os folículos desenvolvidos além da fase II de Christophers e Mer, foi muito pequena, variando de 1,4 a 4,0 por cento . Isso sugeriu a possibilidade da existência de concordância gonotrófica, para as duas supostas populações, nos dois ambientes. A melhor estimativa para a razão de sobrevivência foi de 0,5339 ± 0,047 e 0,5301 ± 0,056 para a população A e de 0,5566 ± 0,015 e 0,3151 ± 0,015 para a população B. No laboratório, procurou-se observar a duração do ciclo gonotrófico e a razão de sobrevivência mediante o acompanhamento diário de coorte de 121 fêmeas, sendo 40 da população A e 81 da população B. A duração do ciclo gonotrófico variou de 2,5 a 3,5 dias para a população A e 2 a 3 dias para a população B e a estimativa da sobrevivência diária variou de 0,35 a 0,79 para a população A e de 0,70 a 0,81 para a população B. Com esses resultados pretendeu-se contribuir para possível estimativa do potencial de transmissão malárica, eventualmente existente na região ou no local. / The basic purpose of the work to determine the parity, the ovarian development and the survivorship rates of these populations. Collection in the field was carried out at Experimental Farm of the \"Instituto Agronômico de Campinas\", and in a locality in the vicinity of \"Barra do Capinzal\", both situated in the Pariquera-Açu Municipality, State of São Paulo, Brazil. Concurrent field collections were also made in extradomiciliary and domiciliary environments using human bait and Shannon traps. Special attention was given to the Anopheles albitarsis complex, with A and B population, in the crepuscular sunset period. Dissections were made according to Polovodova\'s (1949) technique. The method adopted to determine the follicular development was that of Christophers and Mer and the concept was based on the classic school. From 4,170 females dissected, 90.2 per cent were of population B and 9.8 per cent of population A. The overall results concerning the parity showed the nulliparous group to be predominant with 70.0 per cent , uniparous with 25.0 per cent , biparous 2.5 per cent , and the group with three and four dilatations was lower than 1.0 per cent . In relation to the follicular development, the proportion of female above phase 11 of Christophers and Mer, was very small, 1.4 to 4.0 per cent . This suggests that gonotrophic concordance may occur for the two population in both environments. The best estimate for the survivorship rate was 0.5339 ± 0.047 and 0.5301 ± 0.056 to the population A, and 0.5566 ± 0.015 and 0.3151 ±-0.015 to the population B. A study in the laboratory was also carried out to observe the duration of the gonotrophic cycle and the survival rate by daily observation of a cohort of 121 females, 40 of population A and 81 of population B. The duration of the gonotrophic cycle varied from 2.5 to 3.5 days for the population A and from 2 to 3 days for the population B and the estimated daily survival rate was 0.35 to 0.79 to the population A and 0.70 to 0.81 to the population B. With these results, it is intended to contribute for possible estimate of malarian transmission potential, eventually existent in the region or in the local.

A study under controlled conditions of ovarian development and rematuration in the yabby (Cherax destructot) was undertaken. The purpose of the study was to improve fundamental understanding of the reproductive biology of the species and provide a basis for application to hatchery management in culture. A review was made of the current status of yabby culture in Australia and the present understanding of reproductive biology of decapod Crustacea. The review emphasised factors controlling several aspects of ovarian development, in particular the processes of vitellogenesis. The subsequent study was designed within the context of current hatchery practice and was based on existing knowledge of decapod reproduction, The sexual differentiation of the yabby after hatching was investigated by serial histological sections, and experiments were carried out to investigate the possibility of sex reversal of males. Most of this Investigation was concerned with removing the influence of the androgenic gland in directing male development, with the intent of observing the development of the elementary gonadal tissue into ovary. It was found that in contrast to other crustacean species, the sex of the yabby becomes fixed before the development of external secondary sexual characteristics, and before the androgenic gland can be discerned. Ovarian tissue developed in females at less than 8 weeks after hatching. A preliminary examination was undertaken for feminising parasites in gonadal tissue of a hermaphrodite yabby. Investigation of the ovary after spawning demonstrated that whilst the female was held under constant conditions of temperature and photoperiod, little rematuration occurred. Except for generation of previtellogenic oocytes during the first two days, the gonaciosomatic index remained low for up to 5 months after spawning. If the temperature of the female was reduced to 10°C and maintained constant, the previtellogenic oocytes were partially resorbed over a three week period. Rematuration then commenced, albeit at a low rate because of the reduced temperature, A method for standardising gonadosomatic indices was developed which took into account differences in hepatopancreatic nutrient reserves of individuals and loss of one or more appendages. This part of the study also considered constraints to rematuration and developed a method of accounting for differences in the ability of females to remature after spawning. Experiments were carried out to investigate the effect of crowding and temperature manipulation on initiating ovarian rematuration and to determine the rate of rematuration at 22°C once initiated. The duration of low temperature had no effect on rematuration; an overnight cooling was sufficient to initiate the process, Rematuration to the end of stage 2 vltellogenesis was substantially complete within 10 days. Crowding of females suppressed rematuration, but less than ideal water quality was not found to have any effect. The presence of a male initiated rematuration at a similar rate, but also led to stage 3 vitetlogenesis and spawning. A study was made of the pheromonal influence of the male through water borne factors without success. Rematuration could not be induced in ovigerous females. The literature review indicated that ovarian rematuration was under the control of an ovary stimulating hormone produced by the thoracic nerve ganglia. Attempts were therefore made to stimulate ovarian rematuration by incorporating the thoracic nerve into the diet of females. Attempts were also made to induce the release of ovary stimulating hormone from the thoracic nerve with 5-hydroxytryptamine, and also with octopamine. No effects were found, but a significant difference between the neurophysiology of the yabby and northern hemisphere crayfish was observed, and the implications of this finding are discussed. The study did not produce any conclusive evidence of an ovary stimulating hormone for the yabby. A model of ovarian rematuration which collects the findings of the experimental investigations was developed, and was used to suggest a hatchery broodstock management protocol. This model differs from existing models in that rematuration triggers and nutritional status are considered.

Insulin-like growth factors (IGF) are known paracrine/autocrine regulators of ovarian development in teleosts. Initial studies investigated the hormonal and intracellular signal cascades involved in regulating the expression of ovarian-derived IGFs in zebrafish (Danio rerio). Quantitative real-time PCR was used to quantify the expression of igf3, igf2a, and igf2b in full grown immature (FG; 0.57-0.65 mm) and mid-vitellogenic (MV; 0.45-0.56 mm) follicles. Addition of the gonadotropin analogue human chorionic gonadotropin (hCG) and the adenylate cyclase activator forskolin increased igf3 expression in FG and MV follicles, but had no effect on igf2a or igf2b expression. The effects of hCG were blocked by the addition of the protein kinase A inhibitor H-89. Pituitary adenylate cyclase activating peptide stimulated a small increase in igf3 expression in FG follicles, while growth hormone and salmon gonadotropin releasing hormone had no effect on igf3, igf2a, or igf2b expression. Treatment with melittin, prostaglandin F2α, and prostaglandin E2 inhibited igf3 and igf2b expression in FG follicles whereas the protein kinase C activators, PMA and A23187, significantly inhibited igf3, igf2a, igf2b expression in FG and MV follicles. Secondary studies investigated the involvement of ovarian-derived IGFs in mediating the ovarian actions of gonadotropins on cell survival and steroidogenesis. Treatment of FG follicles with recombinant human IGF-I, hCG, or forskolin inhibited the induction of caspase-3/7 activity, which was used as a measure of apoptosis. The effects of hCG and forskolin on caspase-3/7 were attenuated by co-treatment with NVP-AEW54, an IGF-I receptor antagonist. hCG increased production of the maturation-inducing steroid 17α, 20β-dihydroxy-4-pregnen-3-one and co-treatment with NVP-AEW541 had no effect. These results suggest there is a high degree of hormonal specificity in regulating IGFs in the zebrafish ovary and the ovarian-derived IGFs, presumably IGF-III, are downstream mediators of gonadotropin-dependent cell survival, but are not involved in gonadotropin-induced steroidogenesis.

Objetivou-se, principalmente, conhecer a paridade, desenvolvimento ovariano e a razão de sobrevivência dessas populações. As coletas foram realizadas na Fazenda Experimental do Instituto Agronômico de Campinas e em sítio próximo, denominado Barra do Capinzal. Ambos situados no município de Pariquera-Açu, Estado de São Paulo. De maneira concomitante, as capturas foram feitas nos ambientes extradomiciliar e domiciliar, mediante o emprego da isca humana e armadilha tipo Shannon. Focalizou-se o complexo Anopheles albitarsis, populações prováveis A e B, por ocasião do período crepuscular vespertino. As dissecções foram feitas utilizando-se da técnica de Polovodova. Para a avaliação do desenvolvimento folicular, adotou se o critério de Christophers e Mer e o conceito baseado na Escola Clássica. Das 4.170 fêmeas dissecadas, 90,2 por cento foram da população B e 9,8 por cento da população A. Quanto à paridade, o resultado global revelou que o grupo das nulíparas foi predominante, com aproximadamente 70,0 por cento . A uniparidade com aproximadamente 25,0 por cento , a biparidade com aproximadamente 2,5 por cento e o grupo com 3 e 4 dilatações foi inferior a 1,0 por cento . Quanto ao desenvolvimento folicular, a proporção de fêmeas com os folículos desenvolvidos além da fase II de Christophers e Mer, foi muito pequena, variando de 1,4 a 4,0 por cento . Isso sugeriu a possibilidade da existência de concordância gonotrófica, para as duas supostas populações, nos dois ambientes. A melhor estimativa para a razão de sobrevivência foi de 0,5339 ± 0,047 e 0,5301 ± 0,056 para a população A e de 0,5566 ± 0,015 e 0,3151 ± 0,015 para a população B. No laboratório, procurou-se observar a duração do ciclo gonotrófico e a razão de sobrevivência mediante o acompanhamento diário de coorte de 121 fêmeas, sendo 40 da população A e 81 da população B. A duração do ciclo gonotrófico variou de 2,5 a 3,5 dias para a população A e 2 a 3 dias para a população B e a estimativa da sobrevivência diária variou de 0,35 a 0,79 para a população A e de 0,70 a 0,81 para a população B. Com esses resultados pretendeu-se contribuir para possível estimativa do potencial de transmissão malárica, eventualmente existente na região ou no local. / The basic purpose of the work to determine the parity, the ovarian development and the survivorship rates of these populations. Collection in the field was carried out at Experimental Farm of the \"Instituto Agronômico de Campinas\", and in a locality in the vicinity of \"Barra do Capinzal\", both situated in the Pariquera-Açu Municipality, State of São Paulo, Brazil. Concurrent field collections were also made in extradomiciliary and domiciliary environments using human bait and Shannon traps. Special attention was given to the Anopheles albitarsis complex, with A and B population, in the crepuscular sunset period. Dissections were made according to Polovodova\'s (1949) technique. The method adopted to determine the follicular development was that of Christophers and Mer and the concept was based on the classic school. From 4,170 females dissected, 90.2 per cent were of population B and 9.8 per cent of population A. The overall results concerning the parity showed the nulliparous group to be predominant with 70.0 per cent , uniparous with 25.0 per cent , biparous 2.5 per cent , and the group with three and four dilatations was lower than 1.0 per cent . In relation to the follicular development, the proportion of female above phase 11 of Christophers and Mer, was very small, 1.4 to 4.0 per cent . This suggests that gonotrophic concordance may occur for the two population in both environments. The best estimate for the survivorship rate was 0.5339 ± 0.047 and 0.5301 ± 0.056 to the population A, and 0.5566 ± 0.015 and 0.3151 ±-0.015 to the population B. A study in the laboratory was also carried out to observe the duration of the gonotrophic cycle and the survival rate by daily observation of a cohort of 121 females, 40 of population A and 81 of population B. The duration of the gonotrophic cycle varied from 2.5 to 3.5 days for the population A and from 2 to 3 days for the population B and the estimated daily survival rate was 0.35 to 0.79 to the population A and 0.70 to 0.81 to the population B. With these results, it is intended to contribute for possible estimate of malarian transmission potential, eventually existent in the region or in the local.

Orientador: Arício Xavier Linhares / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-25T23:06:38Z (GMT). No. of bitstreams: 1 Ferraz_DaniloRibeiro_M.pdf: 2070808 bytes, checksum: 257105fe3aaa84a8abe9acf46006298a (MD5) Previous issue date: 2014 / Resumo: Os insetos apresentam importância do ponto de vista forense, possibilitando coletar evidências e informações essenciais à justiça. Para o aprimoramento das aplicações da entomologia forense é de extrema importância que sejam realizados estudos relacionados a fisiologia, taxonomia, ecologia, comportamento e distribuição da entomofauna decompositora. Dentre os insetos necrófagos, califorídeos (Diptera) apresentam grande destaque, pois produtos de origem animal são substratos para oviposição e fonte de proteínas e carboidratos para adultos, além de constituir recurso alimentar para larvas de algumas espécies. Os califorídeos passam por diferentes fases de desenvolvimento ovariano sendo que, nos estágios intermediários de desenvolvimento, há intensa deposição de vitelo pelas células tróficas. Assim, com fim de contribuir para um maior entendimento fisiológico e comportamental da família, o presente estudo objetiva avaliar e comparar sua riqueza, observando o padrão de atratividade exercido sobre moscas varejeiras por três diferentes substratos de origem animal (frango, peixe e roedor), bem como os estágios de desenvolvimento ovariano no qual os espécimes coletados se encontravam. Ao todo foram coletados 12.332 espécimes, dos quais 1.432 pertenciam a Calliphoridae. As iscas de moela de frango foram mais atrativas a ordem Diptera, ao passo que a família Calliphoridae foi mais atraída por iscas de roedor. Neste trabalho, 803 fêmeas foram dissecadas, sendo que grande parte destas fêmeas encontravam-se em estágio de vitelogênese completa demostrando a importância da proteína animal como substratos para oviposição / Abstract: Insects are of great forensic importance because they can serve as evidence and provide essential information to justice. In order to improve the applications of forensic entomology, it is of great important to study the biology, ecology, physiology, taxonomy, behavior and distribution of insect fauna associated to decomposing animal matter. Among the scavenger insects, the calliphorids (Diptera) are very important, because many species utilize animal tissues as source of protein and for immature development. Baits of animal origin can act as substrat for oviposition and as source of proteins and carbohydrates for the adults and for larval development feeding .Ovaries of calliphorids undergo different ovarian development phases from the pre-viteloogenic stage to mature eggs. Intermediate phases are characterized by deposition of yolk by the nurse cells. Thus, this study, aimed to contribute to the understanding of the physiological and behavioral characteristics of species of calliphorids, presenting and comparing species richness, attractiveness patterns of three different baits of animal origin these flies (chicken gizzard, fish and rat) as well as the stages of ovarian development in which the collected specimens were found. In all, 12,332 specimens were collected, of which 1,432 belonged to Calliphoridae. The rodent bait was the most attractive to this family while chicken gizzard was more attractive to Diptera as a whole. In this work, 803 females were dissected. The majority of these were in the stage of mature egg, indicating the use of the substracts for oviposition, although this pattern changed depending on the species analyzed / Mestrado / Biodiversidade Animal / Mestre em Biologia Animal

At certain stages of a bumblebee colony life cycle workers lay eggs. Not all workers reproduce, however, since many continue to forage and care for the nest. This leads to questions regarding what differentiates a reproductive worker from a non-reproductive one. It is hypothesized that a form of reproductive competition takes place, where the most behaviourally dominant worker becomes reproductively dominant. The behaviour of orphaned Bombus impatiens pairs was recorded and aggression, social interactions, egg-laying, and ovarian development were identified. Experiment 1 examined the association between aggression and egg-laying. Contrary to the hypothesis, the most aggressive worker did not lay more eggs. When the ovarian development of workers was manipulated and two workers with developed ovaries were paired (Experiment 3), they were more aggressive than pairs with discouraged ovarian development. This provides support for the supposition that aggression and reproduction are related, however, it is only partial support as worker pairs with encouraged ovarian development did not lay more eggs. Since aggression is believed to be only one part of behavioural dominance, Experiment 2 studied the association between social interactions and aggression and reproduction. Results showed that when two socially active bees were paired they were more aggressive than pairs including one or two socially inactive bumblebees. No significant difference in ovarian development between socially active pairs and socially inactive pairs was found. Brood presence was also predicted to affect reproductive control. Experiment 1 found egg-laying and aggression were more likely to co-occur in the absence of brood. Results from Experiment 2 supplemented the first experiment since the absence of brood increased rates of aggression and ovarian development in pairs. Whereas the results confirm aggression has a role in worker reproduction the findings also reveal that behavioural dominance does not equate to reproductive dominance under all conditions. The primary contributions of this thesis were the development of a method to distinguish behavioural dominance from reproductive dominance and determining their relationship under different environments (brood presence) and experimental manipulations (ovarian development). These contributions further define dominance in Bombus impatiens.

At certain stages of a bumblebee colony life cycle workers lay eggs. Not all workers reproduce, however, since many continue to forage and care for the nest. This leads to questions regarding what differentiates a reproductive worker from a non-reproductive one. It is hypothesized that a form of reproductive competition takes place, where the most behaviourally dominant worker becomes reproductively dominant. The behaviour of orphaned Bombus impatiens pairs was recorded and aggression, social interactions, egg-laying, and ovarian development were identified. Experiment 1 examined the association between aggression and egg-laying. Contrary to the hypothesis, the most aggressive worker did not lay more eggs. When the ovarian development of workers was manipulated and two workers with developed ovaries were paired (Experiment 3), they were more aggressive than pairs with discouraged ovarian development. This provides support for the supposition that aggression and reproduction are related, however, it is only partial support as worker pairs with encouraged ovarian development did not lay more eggs. Since aggression is believed to be only one part of behavioural dominance, Experiment 2 studied the association between social interactions and aggression and reproduction. Results showed that when two socially active bees were paired they were more aggressive than pairs including one or two socially inactive bumblebees. No significant difference in ovarian development between socially active pairs and socially inactive pairs was found. Brood presence was also predicted to affect reproductive control. Experiment 1 found egg-laying and aggression were more likely to co-occur in the absence of brood. Results from Experiment 2 supplemented the first experiment since the absence of brood increased rates of aggression and ovarian development in pairs. Whereas the results confirm aggression has a role in worker reproduction the findings also reveal that behavioural dominance does not equate to reproductive dominance under all conditions. The primary contributions of this thesis were the development of a method to distinguish behavioural dominance from reproductive dominance and determining their relationship under different environments (brood presence) and experimental manipulations (ovarian development). These contributions further define dominance in Bombus impatiens.

Made available in DSpace on 2014-12-17T14:10:20Z (GMT). No. of bitstreams: 1 MonicaRO_01_40.pdf: 3996248 bytes, checksum: 971458d8393c9eb3edc1f0eaba559683 (MD5) Previous issue date: 2010-06-08 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The marine fish white mullet, Mugil curema Valenciennes, 1836 (Osteichthyes: Mugilidae) exhibits a wide geographical distribution, being common in the Brazilian coast and is an important component of the artisanal fisheries. The objective of this study was to investigate the reproductive biology of M. curema in the coastal waters of Rio Grande do Norte. Fish samples were captured on a monthly basis during August, 2008 to July, 2009. The fish specimens were numbered, weighed, measured, dissected and their gonads were removed, weighed, their sex and gonadal development were identified. The length-weight relationship was determined for males and females. The sex ratio, the size at first gonadal maturation and gonadosomatic index (GSI) were calculated and ovarian development was investigated using macroscopic and histological techniques. The fecundity, spawning type and the reproductive period of the species were determined. A total of 366 specimens (186 males and 180 females) were captured. The sex ratio was 1:1 and the females were heavier than males. The estimated values of the angular coefficient for both sexes suggest that the species has isometric growth. The size at which 50% of the population began the process of maturation was 25.9 cm of total length for grouped sex. The macroscopic characteristics of the ovaries showed four stages of development: immature, maturing, mature and spent. However, the microscopic characteristics of the ovaries showed five stages of development: immature, early maturing, late maturing, mature and spent. The development of oocytes indicated five phases: Chromatin-nucleolus (phase I), initial perinucleolar (phase II), final perinuclear (phase II), formation of vitelline vesicle or yolk (phase III), vitellogenic (phase IV) and complete vitellogenesis (phase V). The species has a prolonged spawning period, with two peaks coinciding with the rainy season. / O peixe marinho tainha, Mugil curema Valenciennes, 1836 (Osteichthyes:Mugilidae) apresenta ampla distribui??o geogr?fica, sendo comum na costa brasileira e de grande import?ncia para a pesca artesanal. Este trabalho teve como objetivo determinar a biologia reprodutiva de M. curema nas ?guas costeiras do Estado de Rio Grande do Norte. Foram capturados mensalmente exemplares de peixes durante o per?odo de agosto de 2008 a julho de 2009. Os exemplares foram numerados, pesados, medidos, dissecados e suas g?nadas foram retiradas, pesadas e identificadas quanto ao sexo e quanto o desenvolvimento gonadal. A rela??o peso-comprimento foi determinada para machos e f?meas. A propor??o sexual, o tamanho da primeira matura??o gonadal e o ?ndice gonadossom?tico (IGS) foram calculados e o desenvolvimento ovariano foi investigado usando t?cnicas macrosc?picas e histol?gicas. Foram determinados a fecundidade, o tipo de desova e o per?odo reprodutivo da esp?cie. Foi capturado um totalde 366 exemplares (186 machos e 180 f?meas). A propor??o sexual foi de 1:1 e as f?meas foram mais pesadas que os machos. O valor estimado para o coeficiente angular para ambos os sexos sugere que ? a esp?cie apresenta crescimento isom?trico. O tamanho em que 50% da popula??o iniciaram o processo de matura??o gonadal foi de 26 cm de comprimento total para sexo agrupado. As caracter?sticas macrosc?picas dos ov?rios revelaram quatro est?dios de desenvolvimento: imaturo, em matura??o, maduro e esvaziado, enquanto que as caracter?sticas microsc?picas revelaram cinco est?dios de desenvolvimento: imaturo, em matura??o inicial, em matura??o final, maduro e esvaziado. O desenvolvimento dos ov?citos indicou cinco fases: Cromatina-nucl?olo (fase I), perinucleolar inicial (fase II), perinuclear final (Fase II), forma??o ves?cula vitel?nica (fase III), vitelog?nico (fase IV) e vitelog?nese completa (fase V). A esp?cie apresenta um per?odo reprodutivo prolongado, com dois picos coincidindo com o per?ododa chuva

Abstract Mammalian female sex development was considered a default developmental pathway. However, the deletion of the Wnt4 gene, a member of the Wnt family of secreted signals, was shown to reverse the sex of XX female mouse embryo and caused exhibition of certain male characteristics. This indicated that the female sexual development cannot be default but depends on active signaling and cell-cell interaction. The aim of the current study was to reveal the functional role of the Wnt4 gene in the control of sex determination, ovariogenesis and female sex duct formation. This study demonstrates that testosterone is produced by the ovary of Wnt4-deficient female embryos. The inhibition of androgen action by an antiandrogen, flutamide, during gestation leads to complete degeneration of the Wolffian ducts in 80% of the Wnt4 mutant females. This suggests that testosterone is the possible mediator of the masculinization phenotype in Wnt4-deficient females. Wnt4 is expressed by ovarian somatic cells, which are vital for the control of female germline development. This work has shown that Wnt4 is the factor maintaining germ cell cysts, cell-cell interaction and early follicular gene expression. In addition, the findings indicate a critical role for Wnt4/5a signaling in meiosis. Our research has proven that Wnt4 has roles during postnatal ovary development as its defective signaling leads to premature ovarian failure associated with diminished Amh levels, defective basement membrane and cell polarization. The Mullerian duct, the anlagen of oviduct, uterus and upper part of vagina, does not form in Wnt4-deficient females. This study indicates that Wnt4 is needed for migration initiation and maintenance during Mullerian duct formation prenatally. During the postnatal uterine differentiation Wnt4 is essential for endometrial gland formation. The present study provides new evidence for Wnt4 function during embryonic and adult female sexual differentiation. / Tiivistelmä Nisäkkäiden naaraspuolista kehitystä pidettiin aiemmin sukupuolisen erilaistumiskehityksen oletusarvona. Signaloivien proteiinien Wnt-perheeseen kuuluvan Wnt4-geenin puutteen todettiin kuitenkin johtavan XX naarasalkion sukupuolen kääntymisen koiraaksi sekä aiheuttavan tiettyjä koiraille ominaisia piirteitä. Tämä osoitti, ettei naaraspuolinen kehitys ole oletusarvo, vaan se riippuu aktiivisesta signaloinnista ja solujen välisestä interaktiosta. Tämän väitöstutkimuksen tarkoitus oli selvittää Wnt4-geenin roolia sukupuolen määräytymisessä, munasarjojen kehittymisessä sekä naaraan sukupuolitiehyitten muodostumisessa. Tutkimuksessa osoitettiin, että munasarjat tuottavat testosteronia niillä naaraspuolisilla alkioilla, joilta puuttuu Wnt4-geeni. 80 prosentilla naaraista, joilla on Wnt4-geenin puute, androgeenivaikutuksen esto raskauden aikana annettavalla antiandrogeenilla, flutamidilla, estää sukupuolen vaihtumisen fenotyypin. Tämä viittaa siihen, että testosteroni toimii mahdollisena koiraan fenotyypin välittäjänä naarailla, joilta puuttuu Wnt4-geeni. Wnt4 ilmentyy munasarjojen somaattisissa soluissa, jotka ovat tärkeitä naaraspuolisen ituradan kehityksen säätelyn kannalta. Väitöstutkimus osoittaa, että Wnt4 on itusoluryppäitä, solujen välistä interaktiota sekä varhaista follikkeligeeni-ilmentymistä ylläpitävä tekijä. Tulokset osoittavat myös, että Wnt4/5a -signaloinnilla on tärkeä rooli meioosissa. Tutkimus osoittaa lisäksi, että Wnt4 vaikuttaa munasarjojen kehitykseen myös syntymän jälkeen. Puutteellinen signalointi alentaa Anti-Müllerian hormonin tasoa, heikentää tyvikalvoa ja vähentää solujen polarisaatiota, joka johtaa ennenaikaiseen munasarjojen toiminnan hiipumiseen. Müllerin tiehyet, joista myöhemmin kehittyvät munanjohtimet, kohtu ja vaginan yläosa, jäävät kokonaan muodostumatta naarailla, joilta puuttuu Wnt4-geeni. Tulokset viittaavat siihen, että Wnt4 on tarpeen alkioaikaiseen Müllerin tiehyen muodostavien solujen liikkeellelähtöön ja ylläpitoon. Wnt4:llä on myös keskeinen rooli kohturauhasten muodostumisessa sukukypsyyden saavuttamisen aikana ja sen jälkeen.