Consulta: subjectFacets:"Effective population size"
Registros recuperados: 18
Data/hora: 01/06/2024 06:49:56

Historia de vida y genética cuantitativa de cuatro poblaciones del cocodrilo de pantano (Crocodylus moreletii) bajo condiciones de cautiverio en el trópico mexicano.
Provedor de dados: 32
Autores: Serna Lagunes, Ricardo.
Se evaluó la variación morfológica, crecimiento corporal, estructura, variación genética y tamaño efectivo de población (Ne) de cuatro poblaciones de Crocodylus moreletii, manejadas en la UMA Cacahuatal, situada en Veracruz, México. La variación morfológica y el crecimiento corporal se evaluaron aplicando un análisis multivariado de covarianza (MANCOVA) y un análisis de varianza (ANOVA), respectivamente. La descripción de la estructura genética se realizó acorde a los principios de Hardy-Weinberg y se evaluó la variación genética con un análisis de varianza molecular (AMOVA), que se corroboró con los estadísticos F. El Ne se determinó a partir del total de cocodrilos reproductivos y se obtuvo la tasa de incremento de endogamia. La población de Villa Juárez...
Palavras-chave: Morfología; Crecimiento corporal; Estructura genética poblacional; Variación genética; Tamaño efectivo de población; Morphology; Body growth; Genetic structure; Genetic variation; Effective population size; Maestría; Agroecosistemas Tropicales.
Ano: 2010
URL: http://hdl.handle.net/10521/191

Population Genetic Aspects of Pollinator Decline
Provedor de dados: 7
Autores: Packer, Laurence; York University; bugsrus@yorku.ca; Owen, Robin; Mount Royal College and University of Calgary; rowen@mtroyal.ab.ca.
We reviewed the theory of conservation genetics, with special emphasis on the influence of haplodiploidy and other aspects of bee biology upon conservation genetic parameters. We then investigated the possibility that pollinator decline can be addressed in this way, using two meta-analytical approaches on genetic data from the Hymenoptera and the Lepidoptera. First, we compared levels of heterozygosity between the orders. As has been found previously, the haplodiploid Hymenoptera had markedly lower levels of genetic variation than the Lepidoptera. Bees had even lower levels, and bumble bees, in particular, often seemed almost monomorphic genetically. However, the statistically confounding effects of phylogeny render detailed interpretation of such data...
Tipo: Peer-Reviewed Reports
Palavras-chave: Bumble bees; Effective population size; Gene flow; Haplodiploidy; Heterozygosity; Hymenoptera; Lepidoptera; Meta-analysis; Pollinator decline; Population fragmentation; Population genetics.
Ano: 2001

Inbreeding evidence in a traditional channel catfish (Ictalurus punctatus) hatchery in Mexico
Provedor de dados: 69
Autores: Parra-Bracamonte,Gaspar Manuel; Sifuentes-Rincón,Ana María; Rosa-Reyna,Xochitl Fabiola De la; Arellano-Vera,Williams; Sosa-Reyes,Brenda.
Background: Channel catfish are one of the most important aquaculture species raised for food purposes in Mexico. Two temporal samples were obtained from the largest channel catfish breeding hatchery in Mexico to identify changes in genetic diversity and inbreeding that are promoted by traditional hatchery management. Results: The genetic parameter analysis of 11 microsatellite loci showed no significant change in genetic diversity (p &amp;gt; 0.05). However, a significant heterozygosis deficiency was detected (p &lt; 0.001), and genetic structure analysis indicated moderate differentiation between the temporally divided populations (F ST = 0.08). A moderate level of inbreeding and a slight increase of the inbreeding coefficient from 0.23 to 0.27 were the...
Tipo: Journal article
Palavras-chave: Channel catfish; Effective population size; Genetic diversity; Inbreeding.
Ano: 2011
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582011000600011

Decline of genetic variability in a captive population of Pacific white shrimp Penaeus (Litopenaeus) vannamei using microsatellite and pedigree information
Provedor de dados: 69
Autores: Vela Avitúa,Sergio; Montaldo,Hugo H; Márquez Valdelamar,Laura; Campos Montes,Gabriel R; Castillo Juárez,Héctor.
Background: The objective of this study was to estimate the decline of genetic variability and the changes in effective population size in three shrimp populations. One was a wild population collected at several points in the Mexican Pacific Ocean. The other two populations were different generations (7 and 9) from a captive population selected for growth and survival. Microsatellite markers and pedigree were both used to assess genetic variability and effective population size. Results: Using 26 loci, both captive populations showed a decline in the expected heterozygosity (20%) and allelic diversity indices (48 to 91%) compared to the wild population (P &lt; 0.05). The studied captive populations did not differ significantly from each other regarding...
Tipo: Journal article
Palavras-chave: Effective population size; Genetic diversity; Heterozygosity; Microsatellites; Selection; Shrimp.
Ano: 2013
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000400009

Estimation of variance components and prediction of breeding values in rubber tree breeding using the REML/BLUP procedure
Provedor de dados: 74
Autores: Furlani,Renata Capistrano Moreira; Moraes,Mario Luiz Teixeira de; Resende,Marcos Deon Vilela de; Furlani Junior,Enes; Gonçalves,Paulo de Souza; Valério Filho,Walter Veriano; Paiva,João Rodrigues de.
The present paper deals with estimation of variance components, prediction of breeding values and selection in a population of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Müell.-Arg.] from Rio Branco, State of Acre, Brazil. The REML/BLUP (restricted maximum likelihood/best linear unbiased prediction) procedure was applied. For this purpose, 37 rubber tree families were obtained and assessed in a randomized complete block design, with three unbalanced replications. The field trial was carried out at the Experimental Station of UNESP, located in Selvíria, State of Mato Grosso do Sul, Brazil. The quantitative traits evaluated were: girth (G), bark thickness (BT), number of latex vessel rings (NR), and plant height (PH). Given the unbalanced...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Linear mixed model; Effective population size; Breeding strategies; Rubber tree improvement.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000200017

Linkage disequilibrium and past effective population size in native Tunisian cattle
Provedor de dados: 74
Autores: Jemaa,Slim Ben; Thamri,Nejia; Mnara,Sofiane; Rebours,Emmanuelle; Rocha,Dominique; Boussaha,Mekki.
Abstract To carry out effective genome-wide association studies, information about linkage disequilibrium (LD) is essential. Here, we used medium-density SNP chips to provide estimates of LD in native Tunisian cattle. The two measures of LD that were used, mean r2 and D’, decreased from 0.26 to 0.05 and from 0.73 to 0.40, respectively, when the distance between markers increased from less than 20 Kb to 200 Kb. The decay in LD over physical distance occurred at a faster rate than that reported for European and other indigenous breeds, and reached background levels at less than 500 Kb distance. This is consistent with the absence of strong selective pressure within the Tunisian population and suggests that, in order to be effective, any potential genome-wide...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Tunisian cattle; Conservation; Linkage disequilibrium; Effective population size; Single nucleotide polymorphism.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572019000100052

Population bottleneck and effective size in Bonamia ostreae-resistant populations of Ostrea edulis as inferred by microsatellite markers
Provedor de dados: 5
Autores: Launey, Sophie; Barre, Marc; Gerard, Andre; Naciri, Yamama.
Genetic variability at five microsatellite loci was analysed in three hatchery-propagated populations of the flat oyster, Ostrea edulis. These populations were part of a selection programme for resistance to the protozoan parasite Bonamia ostreae and were produced by mass spawns, without control of the genealogy. Evidence for population bottlenecks and inbreeding was sought. A reduction in the number of alleles, mainly due to the loss of rare alleles, was observed in all selected populations, relative to the natural population from which they were derived. Heterozygote excesses were observed in two populations, and were attributed to substructuring of the population into a small number of families. Pedigree reconstruction showed that these two populations...
Tipo: Text
Palavras-chave: Inbreeding; Effective population size; Bonamia ostreae; Ostrea edulis; European flat oyster.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/publication-2703.pdf

Estimating effective population size of large marine populations, is it feasible?
Provedor de dados: 5
Autores: Marandel, Florianne; Lorance, Pascal; Berthele, Olivier; Trenkel, Verena; Waples, Robin S.; Lamy, Jean-baptiste.
stainable exploitation of marine populations is a challenging task relying on information about their current and past abundance. Fisheries‐related data can be scarce and unreliable making them unsuitable for quantitative modelling. One fishery independent method that has attracted attention in this context consists in estimating the effective population size (Ne), a concept founded in population genetics. We reviewed recent empirical studies on Ne and carried out a simulation study to evaluate the feasibility of estimating Ne in large fish populations with the currently available methods. The detailed review of 26 studies found that published empirical Ne values were very similar despite differences in species and total population sizes (N). Genetic...
Tipo: Text
Palavras-chave: Census population size; Effective population size; Fish; Linkage disequilibrium; Management; Simulation.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00470/58162/60678.pdf

Detecting past changes of effective population size
Provedor de dados: 5
Autores: Nikolic, Natacha; Chevalet, Claude.
Understanding and predicting population abundance is a major challenge confronting scientists. Several genetic models have been developed using microsatellite markers to estimate the present and ancestral effective population sizes. However, to get an overview on the evolution of population requires that past fluctuation of population size be traceable. To address the question, we developed a new model estimating the past changes of effective population size from microsatellite by resolving coalescence theory and using approximate likelihoods in a Monte Carlo Markov Chain approach. The efficiency of the model and its sensitivity to gene flow and to assumptions on the mutational process were checked using simulated data and analysis. The model was found...
Tipo: Text
Palavras-chave: Atlantic salmon; Effective population size; Microsatellites; Past demography.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00194/30565/28986.pdf

Estimating effective population size using RADseq: Effects of SNP selection and sample size
Provedor de dados: 5
Autores: Marandel, Florianne; Charrier, Gregory; Lamy, Jean-baptiste; Le Cam, Sabrina; Lorance, Pascal; Trenkel, Verena.
Effective population size (Ne) is a key parameter of population genetics. However, Ne remains challenging to estimate for natural populations as several factors are likely to bias estimates. These factors include sampling design, sequencing method, and data filtering. One issue inherent to the restriction site‐associated DNA sequencing (RADseq) protocol is missing data and SNP selection criteria (e.g., minimum minor allele frequency, number of SNPs). To evaluate the potential impact of SNP selection criteria on Ne estimates (Linkage Disequilibrium method) we used RADseq data for a nonmodel species, the thornback ray. In this data set, the inbreeding coefficient FIS was positively correlated with the amount of missing data, implying data were missing...
Tipo: Text
Palavras-chave: Effective population size; Linkage disequilibrium; NeEstimator; RADseq; Skates and rays.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00607/71934/70628.pdf

Fisheries-induced neutral and adaptive evolution in exploited fish populations and consequences for their adaptive potential
Provedor de dados: 5
Autores: Marty, Lise; Dieckmann, Ulf; Ernande, Bruno.
Fishing may induce neutral and adaptive evolution affecting life-history traits, and molecular evidence has shown that neutral genetic diversity has declined in some exploited populations. Here we theoretically study the interplay between neutral and adaptive evolution caused by fishing. An individual-based eco-genetic model is devised that includes neutral and functional loci in a realistic ecological setting. In line with theoretical expectations, we find that fishing induces evolution towards slow growth, early maturation at small size, and higher reproductive investment. We show, first, that the choice of genetic model (based on either quantitative genetics or gametic inheritance) influences the evolutionary recovery of traits after fishing ceases....
Tipo: Text
Palavras-chave: Eco-genetic model; Effective population size; Fisheries-induced evolution; Genetic drift; Genetic erosion; Genetic markers; Life-history traits; Natural selection and contemporary evolution.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00228/33964/33473.pdf

Genetic characterization of ninety elite soybean cultivars using coefficient of parentage
Provedor de dados: 86
Autores: Miranda,Zilda de Fátima Sgobero; Arias,Carlos Alberto Arrabal; Prete,Cássio Egidio Cavenaghi; Kiihl,Romeu Afonso de Souza; Almeida,Leones Alves de; Toledo,José Francisco Ferraz de; Destro,Deonisio.
The objective of this work was to estimate the coefficient of parentage and to understand the genetic structure of 90 elite soybean cultivars, which are adapted to different Brazilian environments. A total of 4,005 coefficients of parentage (f) were obtained and used to group the cultivars by UPGMA method. The constructed dendrogram showed several related cultivar groups which shared similar ancestors and clearly showed the genetic structure of the main Brazilian cultivars. Effective population sizes (Ne) were also estimated for cultivars in different generations. The average f = 0.2124 value, obtained from cultivars classified into four decades according to the release year, suggested effective soybean population sizes of 11 and 13 calculated using...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Glycine max; Effective population size; Genetic similarity; Parentage coefficient.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2007000300009

Genetic improvement and population structure of the Nelore breed in Northern Brazil
Provedor de dados: 86
Autores: Malhado,Carlos Henrique Mendes; Carneiro,Paulo Luiz Souza; Malhado,Ana Claudia Mendes; Martins Filho,Raimundo; Bozzi,Riccardo; Ladle,Richard James.
The objective of this work was to evaluate the population structure and the genetic and phenotypic progress of Nelore cattle in Northern Brazil. Pedigree information concerning animals born between 1942 and 2006 were analyzed. Population structure was performed using the Endog program. Out of the 140,628 animals studied, 67.7, 14.52 and 3.18% had complete pedigree record of the first, second and third parental generation, respectively. Inbreeding and average relatedness coefficients were low: 0.2 and 0.13%, respectively. However, these parameters may have been underestimated, since information on pedigree was incomplete. The effective number of founders was 370 and the genetic contribution of 10, 50 and 448 most influent ancestors explained 13.2, 28 and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bos taurus indicus; Effective population size; Genetic parameters; Genetic trends; Inbreeding; Pedigree analysis.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2010001000009

Genetic parameters and estimated genetic gains in young rubber tree progenies
Provedor de dados: 86
Autores: Verardi,Cecília Khusala; Scaloppi Junior,Erivaldo José; Silva,Guilherme Augusto Peres; Gouvêa,Lígia Regina Lima; Gonçalves,Paulo de Souza.
The objective of this work was to assess the genetic parameters and to estimate genetic gains in young rubber tree progenies. The experiments were carried out during three years, in a randomized block design, with six replicates and ten plants per plot, in three representative Hevea crop regions of the state of São Paulo, Brazil. Twenty-two progenies were evaluated, from three to five years old, for rubber yield and annual girth growth. Genetic gain was estimated with the multi-effect index (MEI). Selection by progenies means provided greater estimated genetic gain than selection based on individuals, since heritability values of progeny means were greater than the ones of individual heritability, for both evaluated variables, in all the assessment years....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hevea brasiliensis; Annual girth growth; Early selection; Effective population size; Multi-effect index; Rubber yield.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2013000400009

Conservação genética de populações de Cryptocarya moschata Nees (Lauraceae) na Mata Atlântica do estado de São Paulo
Provedor de dados: 88
Autores: MORAES,PEDRO LUÍS RODRIGUES DE; MONTEIRO,REINALDO; VENCOVSKY,ROLAND.
Através da análise de 18 locos isoenzimáticos polimórficos, foram estimadas as freqüências alélicas referentes a 214 indivíduos adultos de quatro populações naturais de Cryptocarya moschata de duas regiões do estado de São Paulo. Com base nas heterozigosidades observadas e esperadas, foram obtidas estimativas das estatísticas F de Wright. Para fins de comparação, utilizou-se também o método da análise da variância para estimação dos parâmetros correspondentes F = FIT, &lt;FONT FACE="Symbol"&gt;q&lt;/font&gt;P= FST e f = FIS. Os dois métodos forneceram resultados bastante concordantes: &lt;img src="http:/img/fbpe/rbb/v22s2/f.gif" alt="f.gif (76 bytes)"&gt;IT = 0,142; &lt;img src="http:/img/fbpe/rbb/v22s2/f.gif" alt="f.gif (76 bytes)"&gt;ST = 0,140; &lt;img...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Genetic structure; Effective population size; Gene flow; Cryptocarya moschata.
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84041999000500004

Population structure and inbreeding of Holstein cattle in southern Brazil
Provedor de dados: 96
Autores: Sieklicki,Michelli de Fátima; Mulim,Henrique Alberto; Pinto,Luís Fernando Batista; Valloto,Altair Antônio; Pedrosa,Victor Breno.
ABSTRACT The present investigation aimed to evaluate the population structure and inbreeding of Holstein herds in southern Brazil. To carry out the analysis, the Associação Paranaense de Criadores de Bovinos da Raça Holandesa (APCBRH) in Brazil provided the data, which consisted of a pedigree file of 206,796 animals born between 1970 and 2014. Results regarding the following parameters were determined: pedigree integrity, effective number of founders, effective number of ancestors, generation interval, inbreeding coefficient, realized effective population size, and average relatedness coefficient. POPREP and ENDOG v.4.5 software packages were employed to estimate these parameters. Based on the data set, the mean generation interval was found to be 6.3...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Effective population size; Founders; Generation interval.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982020000100400

Evaluation of conservation program for the Pantaneiro horse in Brazil
Provedor de dados: 96
Autores: McManus,Concepta; Santos,Sandra Aparecida; Dallago,Bruno Stéfano Lima; Paiva,Samuel Rezende; Martins,Rafhael Felipe Saraiva; Braccini Neto,José; Marques,Pedro Rocha; Abreu,Urbano Gomes Pinto de.
A genealogical analysis of registered Pantaneiro horses was carried out with 3647 males and 6794 females. Of these animals, 50.66% had identified sires and 48.86% identified dams. The number of pedigrees increased over the generations, with higher registration of parents of sires than dams. Two municipalities are responsible for almost 70% of all registers: i) Poconé (Mato Grosso State), where the headquarters of the breeders association is located and ii) Corumbá (Mato Grosso do Sul State), where EMBRAPA Pantanal conducts its research. The mean inbreeding was 0.04% and average relatedness was 0.13%. Mean generation interval was 8.20 years. There is moderate to high genetic differentiation between farms (15% of total genetic variation) while between...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Average relatedness; Effective population size; Farm; Inbreeding; Municipality; Wright's statistics.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982013000600004

Genetic diversity assessment of the Mexican Simmental population through pedigree analysis
Provedor de dados: 96
Autores: Utrera,Ángel Ríos; Murillo,Vicente Eliezer Vega; Bermúdez,Moisés Montaño; Velázquez,Guillermo Martínez; Ponce,Sergio Iván Román.
ABSTRACT The purpose of this study was to examine the genetic variability of the Mexican Simmental. Inbreeding was calculated by year for animals born from 1985 to 2014. Proportion of ancestors known, average equivalent complete generations, generation interval, and effective size, as well as the effective numbers of founders, ancestors, and founder genomes were calculated for animals born in six periods (1985-1989, 1990-1994, 1995-1999, 2000-2004, 2005-2009, and 2010-2014). The year 1985 was selected as the initial year to form the subpopulations since the registration of the first Simmental cattle born in Mexico began in this year. Gene contributions of ancestors with the highest genetic influence were also calculated, using data of animals born in the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Effective number of ancestors; Effective population size; Inbreeding; Marginal genetic contribution; Mexican Simmental cattle.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982018000100404