Consulta: subjectFacets:"Inbreeding depression"
Registros recuperados: 10
Data/hora: 09/06/2024 14:32:08

Contribution of Inbreeding to Extinction Risk in Threatened Species
Provedor de dados: 7
Autores: Brook, Barry W; Northern Territory University; barry.brook@ntu.edu.au; Tonkyn, David W; Clemson University; tdavid@clemson.edu; O'Grady, Julian J; Macquarie University; jogrady@rna.bio.mq.edu.au; Frankham, Richard; Macquarie University; rfrankha@rna.bio.mq.edu.au.
Wild populations face threats both from deterministic factors, e.g., habitat loss, overexploitation, pollution, and introduced species, and from stochastic events of a demographic, genetic, and environmental nature, including catastrophes. Inbreeding reduces reproductive fitness in naturally outbreeding species, but its role in extinctions of wild populations is controversial. To evaluate critically the role of inbreeding in extinction, we conducted realistic population viability analyses of 20 threatened species, with and without inbreeding depression, using initial population sizes of 50, 250, and 1000. Inbreeding markedly decreased median times to extinction by 28.5, 30.5, and 25% for initial populations of 50, 250, and 1000, respectively, and the...
Tipo: Peer-Reviewed Reports
Palavras-chave: Endangered species; Inbreeding depression; Life histories; Median time to extinction; Population viability analysis; Purging.
Ano: 2002

Analysis of general and specific combining abilities of popcorn populations, including selfed parents
Provedor de dados: 74
Autores: Viana,José Marcelo Soriano; Matta,Frederico de Pina.
Estimation of general and specific combining ability effects in a diallel analysis of cross-pollinating populations, including the selfed parents, is presented in this work. The restrictions considered satisfy the parametric values of the GCA and SCA effects. The method is extended to self-pollinating populations (suitable for other species, without the selfed parents). The analysis of changes in population means due to inbreeding (sensitivity to inbreeding) also permits to assess the predominant direction of dominance deviations and the relative genetic variability in each parent population. The methodology was used to select popcorn populations for intra- and inter-population breeding programs and for hybrid production, developed at the Federal...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Diallele cross; Combining ability; Inbreeding depression; Popcorn breeding.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572003000400010

Inbreeding depression of 28 maize elite open pollinated varieties
Provedor de dados: 74
Autores: Pacheco,Cleso Antônio Patto; Santos,Manoel Xavier dos; Cruz,Cosme Damião; Parentoni,Sidney Netto; Guimarães,Paulo Evaristo de Oliveira; Gama,Elto Eugênio Gomes e; Silva,Álvaro Eleutério da; Carvalho,Hélio Wilson Lemos de; Vieira Júnior,Pedro Abel.
The study of inbreeding depression is important for breeding strategies such as use of inbred progenies or extraction of inbreed lines. A diallel of 28 maize open-pollinated varieties was evaluated in 10 environments in the early 1990s. At the same time, S1 populations for each of the 28 varieties were evaluated in the same 10 experiments (environments). Yield reductions of the populations from S0 to S1 (mean of the 10 environments), varied from 34.6% (CMS-01) to 59.2% (CMS-30), with an average of 49.1%. Inbreeding depression was greater in populations with a wider genetic base, which had never been exposed to inbreeding (CMS-30, BR-107, PH4, Cunha, Saracura, Nitrodent, and Nitroflint). Inbred lines with greater yield means should be obtained from the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Inbreeding depression; Endogamy; Maize; Breeding; Diallel.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572002000400014

Evidence of response to unintentional selection for faster development and inbreeding depression in Crassostrea gigas larvae
Provedor de dados: 5
Autores: Taris, Nicolas; Batista, F; Boudry, Pierre.
Underlying consequences of domestication and artificial selection still remain largely unexplored in most aquacultured species. For species with a two phase life cycle, including the Pacific oyster Crassostrea gigas, most genetic studies have focused on the post-metamorphosis juvenile and adult stages, but relatively few considered the larval stage. To assess the consequence of hatchery practices on larval characters, especially growth, we performed a phenotypic study on larval progenies derived from crosses between Pacific oysters from natural beds and farmed Pacific oysters selected for desirable production traits such as rapid growth, for over seven generations. A set of three microsatellite loci was used to compare the genetic variability between the...
Tipo: Text
Palavras-chave: Crassostrea gigas; Inbreeding depression; Selection; Domestication; Larval stage.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3848.pdf

Microsatellite-associated heterosis in hatchery-propagated stocks of the shrimp Penaeus stylirostris
Provedor de dados: 5
Autores: Bierne, Nicolas; Bezuart, Ivan; Vonau, Vincent; Bonhomme, François; Bedier, Edouard.
Correlation between DNA microsatellite heterozygosity and growth rate was investigated in two hatchery-propagated stocks of the shrimp Penaeus stylirostris, which had been genetically isolated from wild founders for 17 generations, and from each other for five more generations. presumed demographic history of these populations suggested that they were maintained at small effective population sizes. and this was confirmed by significant changes in allelic frequencies between the two stocks. Despite a small sample size (n = 60) and a small number of loci screened, a significant positive correlation was detected between microsatellite tri-locus heterozygosity and growth rate in one of the two stocks (r = 0.3, P = 0.02). In the other stock (n = 48), the...
Tipo: Text
Palavras-chave: Penaeus stylirostris; Heterozygosity; Marker associated heterosis; Inbreeding depression; Microsatellites.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/publication-753.pdf

Calculation of Inbreeding Coefficients using Incomplete Pedigrees and its Influence on Inbreeding Depression and Breeding Value for Milk Production in Hokkaido Holstein Populations of Japan
Provedor de dados: 19
Autores: 河原, 孝吉; 後藤, 裕作; 萩谷, 功一; 鈴木, 三義; 曽我部, 道彦.
本分析では, 一般的な方法 (RA) とVanRadenが提案した方法 (VRA) から算出した近交係数を比較検討し, 北海道のホルスタイン集団における近親交配の状況と産乳能力の近交退化および育種価への影響を調査した. 近交係数は, 4,630,163頭の血縁情報を使用し, 再帰的アルゴリズムを用いて算出した. 分析では, 第1に, RAと利用可能なすべての血縁を使用した場合 (RA0), 第2に, RAを使用し, 基礎世代を1950年以前にした場合 (RA50), 第3として, VRAを使用し, 基礎世代を1950年以前にした場合 (VRA50) の3種類の近交係数を算出した. 産乳量の近交退化と育種価は, 1976から2000年8月までに乳期を終了した検定記録から推定した. アニマルモデルには, 近交退化を説明するための偏回帰を含めた. また, 両親の近交係数を使用し, メンデリアンサンプリング分散を補正した. VRA50は, RA50と比較し, 平均近交係数のレベルを高く推定した. RA50とVRA50は, 計算時間の短縮に効果があった. 1960, 1970, 1980, 1990および2000年生まれの雌牛の平均近交係数は, VRA50で各々0.26, 0.56, 1.23, 1.89および4.18%, 種雄牛は各々0.31, 0.43, 0.77, 1.97, および5.14%であった. 1971-1980, 1981-1990および1991-2000年の各期間に生まれた雌牛の年あたり近交係数平均上昇量は, 各々0.07, 0.06および0.22%/年, 種雄牛は各々0.03, 0.12および0.45%/年であった. RA0はVRA50と比較し, 近交退化量を若干低く推定した. 乳量, 乳脂量,...
Palavras-chave: Inbreeding coefficient; Inbreeding depression; Breeding Value; Milk production; Holsteins.
Ano: 2002
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2616

Relationships among Estimates of Additive Genetic Variance, Dominance Genetic Variance and Inbreeding Depression for Type Traits in Holstein Population of Japan
Provedor de dados: 19
Autores: 河原, 孝吉; 後藤, 裕作; 山口, 諭; 鈴木, 三義.
本分析では，ホルスタインの体型形質に関する相加的遺伝分散，優性遺伝分散および近交退化量の関連性を調査した．体型記録は，日本ホルスタイン登録協会北海道支局において1984年4月から2002年3月までの期間に体型審査を実施した244,078頭の雌牛から抽出された．使用した形質は，6の体型得点形質および16の線形式体型形質であった．分析には，母数効果として牛群・年次，泌乳ステージ，審査月齢および近交退化量，変量効果として個体，両親の組合せおよび残差が含まれた単記録モデル（SM），さらに変量として永続的環境効果を追加した反復記録モデル（RM）を使用した．各変量効果の分散成分は，Method Rを使用して推定した．全分散に対する相加的遺伝分散の比率（狭義の牛群内遺伝率）は，SMからの推定値において5.5％（蹄の角度）から45.2％（高さ），RMに関して5.6％（蹄の角度）から46.5％（高さ）の範囲であった．同様に優性遺伝分散の割合は，SMにおいて0.8％（蹄の角度）から7.0％（体積），RMにおいて0.4％（蹄の角度）から6.4％（体積）の範囲で推定された．SMから推定された近交退化量は，尻の角度，後肢側望，前乳房の付着，乳房の深さおよび乳頭の配置に関して正の値（0.000/％から0.012/％），それ以外の形質は−0.046/％（体積）から−0.001/％（後乳房の高さ）の範囲で負の値を示した．RMから推定された近交退化量は，後肢側望および後乳房の高さ以外，SMから推定された近交退化量と傾向が類似していた．相加的遺伝分散の比率と優性遺伝分散の比率との関係は有意（P＜0.01）な正，近交退化量は優性遺伝標準偏差と有意（P＜0.01）な負の関係が認められた．
Palavras-chave: Additive variance; Dominance variance; Holstein; Inbreeding depression; Type trait.
Ano: 2007
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2604

Biologia reprodutiva de Copaifera langsdorffii Desf. (Leguminosae, Caesalpinioideae
Provedor de dados: 88
Autores: FREITAS,CRISTIANE V.; OLIVEIRA,PAULO E.
Copaifera langsdorffii Desf. é uma espécie da família Leguminosae, subfamília Caesalpinioideae, de ampla distribuição no Brasil. O estudo da biologia reprodutiva desta espécie foi realizado numa área de cerradão aberto para pastagem da Fazenda Capim Branco, Uberlândia, MG. A espécie floresce durante o período das chuvas e dispersa suas sementes na época seca. As flores são branco-esverdeadas, com cerca de 0,5 cm de diâmetro, fracamente zigomorfas e estão reunidas em inflorescência paniculada. Apresentam um forte odor adocicado e duram apenas um dia. A antese inicia-se por volta das 5:00 h. Os recursos oferecidos aos visitantes são pólen e néctar. Produzem pouco néctar (0,2 ml) com concentração média de 49% de equivalentes de sacarose. Os visitantes mais...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cerrado; Savanna; Bee pollination; Self-sterility; Inbreeding depression.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042002000300007

Inbreeding on productive and reproductive traits of dairy Gyr cattle
Provedor de dados: 96
Autores: Reis Filho,João Cruz; Verneque,Rui da Silva; Torres,Robledo de Almeida; Lopes,Paulo Sávio; Raidan,Fernanda Santos Silva; Toral,Fabio Luiz Buranelo.
The objective of this study was to estimate genetic parameters and to evaluate the effects of inbreeding on productive and reproductive traits of dairy Gyr cattle. Single-trait animal models were used to estimate genetic parameters and solutions for inbreeding coefficients for milk (milk 305-d), fat (fat 305-d), protein (protein 305-d), lactose (lactose 305-d), and total solids (TS 305-d) yield up to 305 days of lactation, days in milk (DIM), age at first calving (AFC) and calving intervals (CI). The mean inbreeding coefficient was 2.82%. The models with linear and quadratic effects of inbreeding coefficients fitted the data better than the models without or with only linear effect of inbreeding coefficient for all traits. The increase in inbreeding...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Dairy cattle; Genetic parameter; Heritability; Inbreeding depression.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982015000500174

Inbreeding in two maize subpopulations selected for tassel size
Provedor de dados: 63
Autores: Farias Neto,Austeclinio L. de; Miranda Filho,José Branco de.
The present work was based on the evaluation of full sib and S1 progenies from the maize (Zea mays L.) population ESALQ-PB1 after six cycles of divergent selection for tassel size. The following traits were analyzed: plant height , ear height, tassel branch number, tassel length, and tassel weight. For all traits, the experimental units were means of three plants per plot. Progenies were evaluated in eleven experiments (completely randomized blocks) with three replications in Piracicaba -- SP, Brazil. Means of inbred (m1) and non-inbred (m0) progenies were used to estimate inbreeding depression (I = m1 -- m0) and the contribution of homozygotes (mu0 + a*) and heterozygotes (d*) to the population mean. Considering the five traits under study, inbreeding...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Inbreeding depression; Divergent selection; Tassel characters.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162000000300018