The clouded apollo (Parnassius mnemosyne) is a palearctic butterfly with a wide distribution across Eurasia. In recent decades, however, the species has declined in many parts of its distribution range. In Sweden, both the distribution and populations size of the clouded apollo has decreased dramatically over the past two decades, mainly due to habitat loss resulting from changes in land use practices. Today, only three geographically isolated populations remain in Sweden, as well as one captive population. While previous studies have explored the population genetics of other clouded apollo populations across Eurasia, little is known about the genetics of the remaining populations in Sweden. Here we make use of whole genome resequencing data from clouded apollo individuals collected in each of the three natural populations as well as the captive population. We apply population genetic analyses and explore mitochondrial gene data when mapping to two different reference genome assemblies, to get a better understanding of the genetic structure and levels of genetic diversity of the populations in Sweden. Our results show that the clouded apollo populations in different geographic regions harbour similar but relatively low levels of genetic diversity. We also find significant genetic differentiation between the northernmost population and the populations in southern Sweden, as well as higher levels of inbreeding in this population. Our analysis of the mitochondrial CO1 gene coupled with previously available data, shows that the remaining clouded apollo populations in Sweden correspond to two distinct mitochondrial haplogroups characteristic of different regions of Eurasia. Together with our other results, this indicates a re-colonisation of Scandinavia via two different routes after the last glacial maximum. Finally, our analyses uncover sub-population substructure in one of the remaining populations in southern Sweden. Together our results provide a first overview of the populations genetics of the clouded apollo butterfly in Sweden and explore the genetic consequences of populations size declines and fragmentation in the region. These findings were communicated to local conservation authorities and used to inform conservation strategies to protect this endangered species in Sweden.

No description available.

<p> </p> <p>The degree of self-fertilization in a population determines levels of genetic variation and high selfing rates could thus limit future adaptive potential. Theory predicts that intermediate selfing rates should not persist, yet many plants exhibit mixed mating. Cleistogamy is a floral heteromorphism where individuals produce both showy potentially outcrossing chasmogamous flowers and closed obligately selfing cleistogamous flowers. Reproduction via cleistogamous flowers is thought to be beneficial because of their greater energetic economy compared to chasmogamous flowers but can be costly if selfing leads to inbreeding depression or accelerates the fixation of deleterious mutations within populations. Cleistogamy has evolved independently multiple times and can be used to study the maintenance of adaptive mixed mating. To investigate this, I estimated the costs and benefits of selfing in three populations of <em>Ruellia humilis </em>Nutt (Acanthaceae) in greenhouse common garden experiments. To quantify the costs, I performed hand pollinations and quantified fitness components of progeny resulting from selfing and outcrossing within- and between-populations. To quantify the relative energetic advantage of cleistogamous flowers, I measured dry flower mass, fertility, seed number per fruit, and pollen-ovule ratios of both types of flowers. I found negative cumulative inbreeding depression in all populations, indicative of selfed progeny outperforming outcrossed progeny. While the fitness consequences of between population outcrossing ranged from heterosis to outbreeding depression. When looking at the energetic benefits of selfing, I found that the cost of reproduction via cleistogamous flowers was between 3 and 14-fold less than the cost for outcrossing flowers. Finally, I combined data on inbreeding depression and the energetic costs of reproduction and found that chasmogamous flowers of <em>R. humilis </em>must provide between a 3 to a 45-fold fitness advantage to be maintained, the magnitude of which was dependent upon maternal population. Overall, I conclude that none of the existing hypotheses are sufficient enough to provide the selective advantage needed to explain the persistence of chasmogamous flowers in <em>R. humilis</em>. Without any supported explanations for the maintenance of mixed mating, the exploration of genetic constraints on the loss of chasmogamous flowers could solve this long-standing mystery. </p>

Understanding how floral traits covary with one another and with mating patterns is an important step in understanding how and why mating systems evolve. I examined the evolution of floral and mating system variation in Camissoniopsis cheiranthifolia (Onagraceae), a species that exhibits divergence in key floral traits expected to be associated with variation in the relative importance of outcrossing vs. self-fertilization. I combined geographic surveys of floral variation with genetic estimates of the proportion of seeds outcrossed (t) and confirmed that t covaried with corolla width and herkogamy in a predictable way both within and among populations. I then performed geographic surveys, manipulative experiments and genetic analyses to evaluate the potential role that; inbreeding depression (ID), interactions between flowers, pollinators and florivores, and reproductive assurance (RA) may have played in shaping and/or maintaining the geographic pattern of mating system variation in this species. The main selective factor maintaining outcrossing in large flowered (LF) populations appears to be ID, which was much stronger in LF compared to small flowered (SF) populations. These results are also consistent with purging of ID in SF populations. Increased selfing appeared to alleviate pollen limitation (PL) because it was associated with higher and less variable fruit set and reduced florivory by a microlepidopteran. However, evidence that florivores preferentially attacked larger flowers was equivocal. LF experienced stronger PL than SF populations suggesting that one condition for the evolution of selfing via RA is met in outcrossing populations. Floral emasculation experiments revealed that the timing of selfing also covaried with flower size among and within populations. SF self-pollinate before flowers open but LF do not, suggesting that selfing evolved in response to chronic outcross PL. Negative side effects of emasculation were detected which prevented a clear interpretation of the RA value of selfing. Given that much of what is known about RA comes from emasculation experiments, my results suggest that the assumptions of this approach, which are rarely verified, require more serious consideration. Taken together my results suggest that C. cheiranthifolia has evolved multiple stable mixed mating systems perhaps in response to selection for RA. / Thesis (Ph.D, Biology) -- Queen's University, 2012-12-30 14:13:46.366

I examined the population genetic structure of three known subspecies of Glaucomys sabrinus from Appalachia, Washington State, and two previously unexamined populations from Mount Rogers National Recreation Area (MRNRA) in Southwestern Virginia. Mean FST (0.107) and an AMOVA (P G. sabrinus subspecies populations in the southern Appalachians are genetically differentiated. Glaucomys sabrinus at MRNRA were less inbred than expected. Gene flow, a consensus tree based on Nei's genetic distance, elevated heterozygosity and morphometric data suggest that the MRNRA G. sabrinus population is an intergrade of the two recognized Appalachian subspecies, G. s. fuscus and G. s. coloratus. I compared inbreeding and the level of parasite infestation in the two MRNRA populations of G. sabrinus and found that Whitetop Mountain (150 ha habitat) was more inbred than the population on Mount Rogers (400 ha habitat, P Strongyloides robustus were greater in the more fragmented Whitetop Mountain population, although the difference was not statistically significant (P= 0.278). A Mantel comparison of genetic diversity and parasite infestation among individuals did show a highly significant negative correlation (P G. sabrinus form a unique insular population with high genetic diversity that is nonetheless susceptible to increased inbreeding, and elevated parasitism caused by fragmentation. MRNRA G. sabrinus should retain endangered species status.

O bioma Mata Atlântica tem sofrido com a fragmentação florestal e como forma de reestabelecer ambientes florestais são realizados plantios de restauração. Porém, por muito tempo houve preocupação somente com a composição florística das áreas e a diversidade genética foi negligenciada. Além disso, muitas áreas são implantadas a partir de sementes coletadas em áreas florestais geralmente pouco conservadas, pequenas e isoladas, o que pode comprometer a qualidade genética das mudas, produzindo indivíduos menos adaptados em decorrência da depressão endogâmica. Assim este trabalho teve como objetivo principal analisar o aspecto genético em áreas de restauração na região do Pontal do Paranapanema e área natural de referência, o Parque Estadual Morro do Diabo (PEMD), utilizando o jatobá (Hymenaea courbaril L.) como espécie modelo. No capítulo 1 com o objetivo de verificar a diversidade genética de H. courbaril em áreas de restauração florestal, foram selecionadas duas áreas de plantio com espécies nativas. Nestas áreas e no PEMD foram coletadas amostras foliares de indivíduos adultos que foram genotipadas para oito locos microssatélites. No PEMD ainda foram coletados frutos em 12 matrizes para caracterização do sistema reprodutivo. As três áreas estudadas apresentaram diversidade genética e níveis de endogamia similares. Nas três áreas de estudo foi identificada baixa estruturação genética espacial. Houve predomínio de fecundação cruzada para a produção de frutos na área natural, porém a taxa de cruzamentos entre indivíduos aparentados foi até dez vezes maior que a observada em outras populações da espécie. No capítulo 2 com o objetivo de verificar se há depressão endogâmica em progênies provenientes do PEMD foram selecionadas 320 sementes de 12 matrizes. Estas e seus frutos foram medidos. As plântulas a que deram origem também foram mensuradas, mensalmente, durante 15 meses. Todos os indivíduos foram genotipadas para oito locos microssatélites. A coancestria, foi estimada e os indivíduos separados em: não aparentados (tu), aparentados (tr) e autofecundação (s). Foi verificada diferença entre as métricas das plantas de acordo com o nível de coancestria entre indivíduos. Também foram estimados os valores de depressão endogâmica (ID). A quantidade de indivíduos irmãos de autofecundação foi muito pequena, sendo a maioria proveniente de cruzamento entre indivíduos não aparentados. A depressão endogâmica por autofecundação foi mais evidente no peso e tamanho dos frutos, e amena ou inexistente para os demais caracteres. Isto provavelmente por estas sementes terem sido coletadas em um fragmento grande e bem conservado e que ainda não sofre as consequências da depressão endogâmica. Assim, nosso trabalho mostrou que áreas de restauração florestal que seguiram as recomendações genéticas de implantação, apresentam diversidade genética suficiente para H. courbaril, podendo estas áreas serem fonte de coleta de sementes no futuro. E que os indivíduos provenientes de sementes do PEMD não apresentaram efeito de depressão endogâmica até 15 meses de desenvolvimento em viveiro. / The Brazilian Atlantic Forest was severely deforested and restoration initiatives are necessary to reestablish environments. However, for a long time there is only concern over floristic composition and the genetic diversity has been neglected. In addition, several restoration areas are planted from seeds collected in forest areas that are generally poorly preserved, small and isolated, which may compromise the genetic quality of the seedlings, producing less adapted individuals due to inbreeding depression. The aim of this work was to analyze the genetic aspects of Hymenaea courbaril L. in restoration areas in Pontal do Paranapanema region, and a natural reference forest, the Morro do Diabo State Park (PEMD), where seeds were also collected. In Chapter 1, to verify the genetic diversity of H. courbaril in areas of forest restoration, using eight microsatellites, two restoration areas were selected. In these areas and in the PEMD, leaf samples from adult individuals were collected. In the PEMD, fruits were collected in 12 seed trees for mating system characterization. The three areas presented similar genetic diversity and levels of inbreeding. Low spatial genetic structure was identified in the three studied areas. In the natural forest, fruits were mainly produced through outcrossings, but the rate of mating among relatives was up to ten times higher than the observed in other H. courbaril populations. In Chapter 2, to verify the inbreeding depression in the PEMD were selected 320 seeds from eight seed trees. The seeeds and their fruits were measured. The seedlings were also measured monthly, during 15 months. All seedlings were genotyped with eight microsatellite loci. From the pairwise coancestry the seedlings were separated into three categories: outcrossing among unrelated individuals (tu), outcrossing among related individuals (tr), and selfing (s). We verified differences among groups in the metrics of seedlings according to the level of coancestry among individuals. The values of inbreeding depression (ID) were also estimated. The number of selfed seedlings were very small, and the majority were from outcrossing among unrelated individuals. Inbreeding depression by selfing was more evident in weight and size fruit, and was insignificant or non-existent for other characters. This is probably because these seeds were collected in a large and preserved forest fragment, that does not suffer the consequences of inbreeding depression yet. Thus, our work showed that forest restoration areas that followed the genetic recommendations present enough genetic diversity for H. courbaril, and these areas may be a source of seeds for collection in the future. Besides that, seedlings from seed trees in PEMD did not present inbreeding depression effect up to 15 months of nursery development.

Os objetivos do presente trabalho se dirigem ao estudo da variabilidade genética e da depressão por endogamia em sete populações de milho de ampla base genética, visando ao melhoramento de populações e obtenção de linhagens endogâmicas promissoras. Foram instalados onze experimentos em blocos casualizados em um local (Anhembi, SP), com diferentes conjuntos (N) de progênies S1 obtidos de sete populações (GO-D: dentado, GO-F: flint, GO-L: espiga longa, GO-G: espiga grossa; e compostos G3, G4 e GO-S). Foram estimadas a variância genética entre médias de progênies (2G), a variância fenotípica entre médias de progênies?^ (2F?^) e o coeficiente de herdabilidade (sentido amplo) para médias de progênies (2X). As estimativas de h 2Xhforam altas para peso de espigas (PE: 0,89 a 0,94), comprimento da espiga (CE: 0,77 a 0,88) e diâmtero da espiga (DE: 0,77 a 0,92); e menores para altura da planta (AP: 0,58 a 0,80) e altura da espiga (AE: 0,54 a 0,84), demonstrando alto potencial das populações para seleção recorrente com progênies S1. A variável PE nas populações base usadas como testemunha, mostrou valores variando de 11200 kg.ha-1 (GO-D) a 12800 kg.ha-1 (G3). As médias de progênies S1 entre populações variaram de 6070 kg.ha-1 (GO-F) a 7380 kg.ha-1 (G4); a depressão por endogamia nas progênies S1 variou de 37,5% (G4) a 48,0% (G3) em relação à população base. Os estudos sobre endogamia envolvendo as sete populações foram conduzidos com amostras da população original não endógama (S0) e das gerações S1 e S2 de autofecundação. Os experimentos foram conduzidos em Londrina (PR) e Piracicaba (SP) em blocos casualizados com parcelas subdivididas, com as populações representadas nas parcelas e as gerações de endogamia nas sub-parcelas. A estimação da depressão por endogamia foi obtida pelo modelo de regressão linear Y = µ0 + ?, sendo ? a depressão por endogamia para 100% de homozigose. A depressão esperada para 50% de homozigose é ?/2, cujo valor em percentagem variou de 25,4% a 41,4% em Piracicaba e de 23,1% a 39,3% em Londrina. Para os demais caracteres, os efeitos depressivos foram menores, geralmente <25% para AP e AE e <15% para DE e CE. / The objectives of the present work were directed for the study of genetic variability and inbreeding depression in seven maize populations of broad genetic base, as a guide for population improvement and development of promising inbred lines. The field evaluation was in eleven experiments (randomized complete blocks) in one location (Anhembi, SP) with different groups (N) of S1 progenies obtained of seven populations (GO-D: dent type, GO-F: flint type, GO-L: long ear, GO-G: thick ear; and composites G3, G4 e GO-S). Estimates were obtained for genetic variance (?^: progeny mean basis), phenotypic variance of progeny means (2G2F?^), and coefficient of heritability (broad sense) for progeny means (2Xh). Estimates of 2Xhwere high for ear weight (PE: 0.89 to 0.94), ear length (CE: 0.77 to 0.88) and ear diameter (DE: 0.77 to 0.92); and lower for plant height (AP: 0.58 to 0.80) and ear height (AE: 0.54 to 0.84), thus showing the high potential of the populations for recurrent selection based on S1 progenies. Ear yield (PE) in the base populations used as ckecks varied from 11200 kg.ha-1 (GO-D) to 12800 kg.ha-1 (G3). The means of S1 progenies varied from 6070 kg.ha-1 (GO-F) to 7380 kg.ha-1 (G4); the inbreeding depression in S1 progenies varied from 37.5% (G4) to 48.0% (G3) relative to the non-inbred population. For the studies on inbreeding in the seven populations samples of the original non-inbred populations (S0) and S1 and S2 generations of inbreeding were used. Filed experiments were carried out in Londrina (PR) and Piracicaba (SP) in randomized blocks with spli-plots, where populations were in the whole plots and inbreeding generations in the sub-plots. The estimates of inbreeding depression were obtained by the linear regression model Y = µ0 + ?, where ? is the iinbreeding depression for 100% homozygosity. The expected inbreeding depression for 50% homozygosity is ?/2, and the estimates in percentage varied from 25.4% to 41.4% in Piracicaba and from 23.1% to 39.3% in Londrina. For the other traits the inbreeding effects were lower, in general <25% for AP and AE and <15% for DE and CE.

O objetivo deste trabalho foi analisar a estrutura genética populacional e os efeitos do programa de melhoramento genético em um rebanho Nelore comercial, que visa a venda de reprodutores avaliados geneticamente. O banco de dados era composto pelos registros de produção de 417.552 animais, nascidos entre 1984 e 2007, e o de pedigree de 483.748 animais. Com o intuito de estudar a estrutura populacional, foram utilizados os softwares ENDOG v. 4.6 e POPREPORT para se calcular o coeficiente de endogamia (F), o coeficiente médio de parentesco individual (AR), numero efetivo de ancestrais e de fundadores, numero de ancestrais que contribuem com 50% da variabilidade genética da população e intervalo de gerações. O coeficiente de endogamia calculado para a população em estudo foi igual a 0,12% e o AR a 0,18%. Os números efetivos de ancestrais (fa) e de fundadores (fe) foram iguais a 64 e 147, respectivamente. Para a população estudada, 70 indivíduos explicam sua variabilidade genética. O intervalo de geração calculado para os quatro passos gaméticos pai-filho, pai-filha, mãe-filho, mãe-filha foram de 9,26, 7,30, 9,29 e 5,83 anos, respectivamente, quando se considera somente as progênies que se tornaram reprodutores no programa de melhoramento, e de 7,45, 7,40, 6,02, 5,93 anos, respectivamente, quando se considera todas as progênies nascidas. O progresso genético esperado para as características peso a desmama (PD), ganho de peso da desmama ao sobreano (GP345), perímetro escrotal (PE) e musculatura era de 1,10 kg/ano, 1,05 kg/ano, 0,28 cm/ano e 0,04 un/ano, respectivamente. Entretanto, o progresso genético observado para as mesmas características foram iguais a 0,51 kg/ano, 1,03 kg/ano, 0,11 cm/ano e 0,03 un/ano, respectivamente. / The objective of the present research was to analyze the population genetic structure and the effects of breeding program in a Nellore commercial herd, aimed at the sale of breeders genetically evaluated. The database was composed by production records by 417552 animals, born between 1984 and 2007, and the pedigree records by 483748. For describe the population structure, to ENDOG v. 4.6 and POPREPORT were used to calculate inbreeding coefficient (F), average relatedness coefficients (AR), effective number of ancestors and founders, number of ancestors that contribute with 50% of genetic variability of population and generation intervals. The inbreeding coefficient calculated to the population in study is 0.12% and AR is 0.18%. The effective number of ancestors (fa) and founders (fe) was 64 and 147, respectively. For the population in study, 70 individuals explain 50% of genetic variability. The generation\'s intervals for the four paths genetic, sire-son, siredaughter, dam-son, dam-daughter, was 9,26, 7,30, 9,29 e 5,83 years, respectively, when considered only progenies kept reproduction, and was 7,45, 7,40, 6,02, 5,93 years, respectively, when all born progenies are considered. The genetic progress waited to the characteristics weaning weight (WW), weight gain from weaning to 18 months (WG345), scrotal circumference (CE) and muscle were 1.10 kg.year-1, 1.05 kg.year-1, 0.28 cm.year-1 and 0.04 unit.year-1, respectively. However, the genetic progress observed to the same characteristics was 0.51 kg.year-1, 1.03 kg.year-1, 0.11 cm.year-1 and 0.03 unit.year-1, respectively.

O presente estudo teve como objetivo avaliar a estrutura populacional, estimar parâmetros (coeficientes de herdabilidade e correlações) e determinar as tendências genéticas e fenotípicas de características de crescimento e adaptação em bovinos da raça Nelore, linhagem Lemgruber. O banco de dados utilizado nas análises constituiu-se de 39.290 animais no arquivo de pedigree e de 24.353 animais no arquivo de produção. Os parâmetros populacionais foram obtidos por meio dos softwares POPREP (GROENEVELD et al., 2009) e ENDOG v 3.2 (GUTIÉRREZ e GOYACHE, 2005). As estatísticas descritivas e os parâmetros genéticos para cada característica estudada foram estimadas por meio de quatro análises hepta-característica utilizando o programa VCE-6 (KOVAC & GROENEVELD, 2003) sob modelo animal completo. As tendências genéticas e fenotípicas foram obtidas pela regressão dos valores genéticos e fenotípicos respectivamente sobre o ano de nascimento dos animais e os coeficientes da regressão foram estimados por meio do método de quadrados mínimos. Apesar da endogamia média do rebanho ser considerada moderada verificou-se alta porcentagem de indivíduos endogâmicos e reduzido tamanho efetivo populacional. Além disso, o incremento contínuo de endogamia ao longo dos anos demonstra a necessidade de intervenção na seleção dos indivíduos para reprodução, de modo que, problemas futuros possam ser evitados. Os coeficientes de herdabilidade direta foram estimados em 0,24, 0,31, 0,31, 0,21, 0,19, 0,30, 0,41, 0,19 e 0,17 respectivamente para peso ao nascimento (PN), peso aos 120 dias de idade (P120), peso à desmama (PD), peso ao ano (PES12), ganho de peso pós desmama, de 205 aos 550 dias (GP345), ganho de peso na prova à pasto da ABCZ, em 224 dias (GP224), perímetro escrotal (PE), temperamento (TEMP), e repelência (REP) e indicam que a variabilidade genética aditiva existente é suficiente para a obtenção do ganho genético em resposta à seleção desde que sejam realizados ajustes, tanto nas estratégias de seleção adotadas para a obtenção de maiores ganhos nos valores genéticos, como também nos fatores ambientais que possam possibilitar ao máximo, a expressão do potencial genético dos animais. / The present study had as objective to evaluate the population structure, to estimate parameters (coefficients of heritability and correlation) and to determine the phenotypic and genetic trends for growth and adaptability traits in Nellore cattle, Lemgruber line. The database used in the analysis consisted of 39,290 animals in the pedigree and 24,353 animals in the production file. The population parameters were obtained from the software POPREP (Groeneveld et al., 2009) and ENDOG v 3.2 (Gutierrez and GOYACHE, 2005). The descriptive statistics and genetic parameters for each characteristic studied were estimated by four seven-traits analysis using the program VCE-6 (Kovac & GROENEVELD, 2003) which uses the animal model. The phenotypic and genetic trends were obtained by means of phenotypic and genetic values respectively on the year of birth of the animals and the regression coefficients were estimated by the method of least squares. Although the average inbreeding of the herd being considered moderate, there was high percentage of inbred individuals and small effective population size. Furthermore, the continuous increase in inbreeding over the years demonstrates the need for intervention in the selection of individuals for reproduction, so that future problems can be avoided. Direct heritability coefficients were estimated as 0.24, 0.31, 0.31, 0.21, 0.19, 0.30, 0.41, 0.19 and 0.17 respectively for birth weight (PN), weight 120 days of age (P120), weaning weight (PD), weight at 12 months of age (PES12), weight gain after weaning from 205 to 550 days (GP345), weight gain during the pasture test of ABCZ in 224 days (GP224), scrotal circumference (PE), docility (TEMP) and repellency (REP) and indicate that the additive genetic variability is sufficient to obtain genetic gain in response to selection as far as adjustments in selection strategies are adopted to achieve larger gains in breeding values, and environmental factors that may allow the expression of the genetic potential of the animals.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-07T12:52:48Z No. of bitstreams: 1 Ana Patricia Souza de Lima.pdf: 977295 bytes, checksum: 33939fc8bb3c79d0da66b07e710666b5 (MD5) / Made available in DSpace on 2017-02-07T12:52:48Z (GMT). No. of bitstreams: 1 Ana Patricia Souza de Lima.pdf: 977295 bytes, checksum: 33939fc8bb3c79d0da66b07e710666b5 (MD5) Previous issue date: 2007-02-07 / Although Brazil has an an important position in the world shrimp farming industry scenario, information on the genetic basis of the most important species, the exotic Litopenaeus vannamei, still scarce. The Brazilian shrimp industry has been facing difficulties, such as US antidumping action against shrimp products, unfavorable currency exchange rate impacts and viruses outbreaks. Shrimp resistant to viral diseases, as well as with better growth rates are wanted in breeding programs for this species in Brazil. A Federal Normative Instruction, instituted in 1997, prohibited shrimp importation into Brazil as a sanitary precaution to prevent the spread of shrimp diseases, and since then, all shrimp broodstock rely on the domesticated stocks. This fact raises questions about the success of a breeding program on this species, because one can not know if the genetic variability is enough to guarantee selection response. The objective of this study was to genetically characterize the broodstock of two shrimp hatcheries and to monitor the genetic variability of one of them after three consecutive broodstock replacements in the state of Pernambuco, Northeast Brazil. Genetic characterization of the two hatcheries was carried out using 5 microsatellite loci and pleopods tissue samples taken from 100 shrimp (50 of each broodstock). For the monitoring 3 microsatellite loci were used in 150 shrimp samples (50 of each broodstock replacement). Our results showed that there is sufficient genetic variability in both hatcheries based on the alleles frequency, inbreeding coefficient, FIS (Larv. A = 0,380 e Larv. B = 0,250), and observed and expected heterozygosities ranging from Ho= 0,190 to 0,810 and He= 0,460 to 0,870,respectively. The monitoring results showed that in closed systems, broodstock replacement does not interfer in the genetic variability, based on the alleles frequency, observed and expected heterozygosities (Ho= 0,460 and He= 0,660 in first sample collection, Ho= 0,420 and He= 0,620 in the second sample collection and Ho= 0,600 and He= 0,660 in the third sample collection), inbreeding coefficient, FIS (0,37 for the 1st, 0,39 for the 2nd and 0,13 for the 3rd sample collection). Our results suggested that genetic variability is high, thus reflecting the history of the shrimp activity in Brazil, where broodstock from different origins were introduced in the country up to 1997. / Desde 1997 a introdução de novos reprodutores de Litopenaeus vannamei está proibida pelo o Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (IBAMA), Portaria de nº. 119, o que levanta questões sobre a viabilidade de programas de melhoramento no Brasil, uma vez que não há mais renovação dos plantéis. O objetivo do presente trabalho foi caracterizar geneticamente duas larviculturas de Litopenaues vannamei e monitorar a variabilidade genética de uma das larviculturas, com reposição de matrizes, em três períodos sucessivos, ambas, localizadas no estado de Pernambuco, Nordeste do Brasil. A caracterização genética foi feita usando 5 loci de microssatélites e um total de 100 amostras teciduais de reprodutores, para o monitoramento foram utilizados 3 loci de microssatélites e um total de 150 amostras teciduais de reprodutores. Foi evidenciado que há variabilidade genética suficiente nas duas larviculturas, para subsidiar programas de melhoramento genético, baseado na freqüência dos alelos, nos coeficientes de endogamia FIS (Larv. A = 0,380 e Larv. B = 0,250) e heterozigosidades que variaram de Ho= 0,190 a 0,810 e He= 0,460 a 0,870, respectivamente. Os resultados do monitoramento mostraram que a reposição de matrizes no sistema de ciclo fechado não interferiu na variabilidade genética desta larvicultura, o que pode ser evidenciado através da freqüência dos alelos, nas heterozigosidades obtidas que foram de Ho= 0,460 e He= 0,660 na primeira coleta, de Ho= 0,420 e He= 0,620 na segunda coleta e de Ho= 0,600 e He= 0,660 na terceira coleta, e nos valores do coeficiente de endogamia FIS (0,37 para a primeira coleta, 0,39 para a segunda coleta e 0,13 para a terceira coleta) encontrados. Os resultados aqui relatados podem ser considerados bons, refletindo a história da atividade no Brasil que se destacou pela introdução de reprodutores de diversas origens.