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| Registros recuperados: 18 | |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| Registros recuperados: 18 | |
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