Dynamic selection procedures for constrained inbreeding 
and their consequences for pedigree development

Grundy, B.; Villanueva, B.; Woolliams, John

doi:10.1017/s0016672398003474

Cited by 153 publications

(162 citation statements)

References 14 publications

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“…Ballou and Lacy (1995) from a conservation perspective, and Wray and Goddard (1994), Meuwissen (1997) and Grundy et al (1998) in the context of animal breeding, proposed using coancestry as the decision criterion when determining the contributions from each candidate. The optimal strategy looks for the set of contributions that minimises the global coancestry of the candidates, weighted by their particular contributions.…”

Section: Managing the Contributions Of Individualsmentioning

confidence: 99%

“…The most sophisticated way of managing genetic contributions is selection with optimal contributions (Meuwissen, 1997;Grundy et al, 1998). The problem to be solved is the allocation of the contributions of the candidates to selection so as to maximise genetic gain with restrictions on DF and can be formulated as maximise c 0 g subject to 1 2 c 0 AcoC and Q 0 c p 1…”

Section: Selection With Optimal Contributionsmentioning

confidence: 99%

“…Computer simulations studies have evaluated the potential utility of most of the methods for managing genetic diversity in selection and conservation programmes (Toro and Nieto, 1984;Toro et al, 1988 and1991;Meuwissen, 1997;Grundy et al, 1998;Oliehoek et al, 2006;Oyama et al, 2007 and more), although they have assumed oversimplified genetic models for the characters examined, with additive and homogeneous gene effects, and simple mechanisms of inbreeding depression. However, experiments have been performed using populations in laboratories and on farms, and a short review of some of these experiments is presented below.…”

Section: Practical Applications Of Pedigree-based Managementmentioning

confidence: 99%

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Management of genetic diversity in small farm animal populations

Fernández

Meuwissen

Toro

et al. 2011

Animal

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Many local breeds of farm animals have small populations and, consequently, are highly endangered. The correct genetic management of such populations is crucial for their survival. Managing an animal population involves two steps: first, the individuals who will be permitted to leave descendants are to be chosen and the number offspring they will be permitted to produce has to be determined; second, the mating scheme has to be identified. Strategies dealing with the first step are directed towards the maximisation of effective population size and, therefore, act jointly on the reduction in the loss of genetic variation and in the increase of inbreeding. In this paper, the most relevant methods are summarised, including the so-called 'Optimum Contribution' methodology (contributions are proportional to the coancestry of each individual with the rest), which has been shown to be the best. Typically, this method is applied to pedigree information, but molecular marker data can be used to complete or replace the genealogy. When the population is subjected to explicit selection on any trait, the above methodology can be used by balancing the response to selection and the increase in coancestry/inbreeding. Different mating strategies also exist. Some of the mating schemes try to reduce the level of inbreeding in the short term by preventing mating between relatives. Others involve regular (circular) schemes that imply higher levels of inbreeding within populations in the short term, but demonstrate better performance in the long term. In addition, other tools such as cryopreservation and reproductive techniques aid in the management of small populations. In the future, genomic marker panels may replace the pedigree information in measuring the coancestry. The paper also includes the results of several experiments and field studies on the effectiveness and on the consequences of the use of the different strategies.

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Section: Managing the Contributions Of Individualsmentioning

confidence: 99%

Section: Selection With Optimal Contributionsmentioning

confidence: 99%

Section: Practical Applications Of Pedigree-based Managementmentioning

confidence: 99%

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Management of genetic diversity in small farm animal populations

Fernández

Meuwissen

Toro

et al. 2011

Animal

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“…After stabilisation, an ancestor makes the same long-term contribution to all descendants, with the contributions differing between ancestors. The minimum rate of inbreeding that can be generated, given the genetic gain obtained by truncation selection (or any other selection system), is when an exact linear relationship exists between the long-term contributions of the ancestors and their Mendelian sampling terms (Lindgren and Matheson, 1986;Grundy et al, 1998;Woolliams et al, 2002). This implies that the more ancestors that make a long-term genetic contribution, and the closer their contributions stabilise to the exact linear relationship, the lower the rate of inbreeding.…”

Section: Introductionmentioning

confidence: 99%

Mating animals by minimising the covariance between ancestral contributions generates less inbreeding without compromising genetic gain in breeding schemes with truncation selection

Henryon

Sørensen

Berg

2009

Animal

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We reasoned that mating animals by minimising the covariance between ancestral contributions (MCAC mating) will generate less inbreeding and at least as much genetic gain as minimum-coancestry mating in breeding schemes where the animals are truncation-selected. We tested this hypothesis by stochastic simulation and compared the mating criteria in hierarchical and factorial breeding schemes, where the animals were selected based on breeding values predicted by animal-model BLUP. Random mating was included as a reference-mating criterion. We found that MCAC mating generated 4% to 8% less inbreeding than minimum-coancestry mating in the hierarchical and factorial breeding schemes without any loss in genetic gain. Moreover, it generated upto 28% less inbreeding and about 3% more genetic gain than random mating. The benefits of MCAC mating over minimum-coancestry mating are worthwhile because they can be achieved without extra costs or practical constraints. MCAC mating merely uses pedigree information to pair the animals more appropriately and is clearly a worthy alternative to minimum-coancestry mating and probably any other mating criterion. We believe, therefore, that MCAC mating should be used in breeding schemes where pedigree information is available.

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“…These schemes were, however, not compared at the same rate of inbreeding. Optimum contribution selection is a group selection method that maximises genetic gain with a restriction on ∆F for schemes with both discrete [9,17] and overlapping [10,18] generations. It is dynamic, such that it adapts to current selection candidates, and can therefore correct skewnesses in contribution of families over generations.…”

Section: Introductionmentioning

confidence: 99%

A combination of walk-back and optimum contribution selection in fish: a simulation study

Sonesson

2005

Genet. Sel. Evol.

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-The aim of this paper was to study the performance of a novel fish breeding scheme, which is a combination of walk-back and optimum contribution selection using stochastic simulation. In this walk-back selection scheme, batches of different sizes (50, 100, 1000, 5000 and 10 000) with the phenotypically superior fish from one tank with mixed families were genotyped to set up the pedigree. BLUP estimated breeding values were calculated. The optimum contribution selection method was used with the rate of inbreeding (∆F) constrained to 0.005 or 0.01 per generation. If the constraint on ∆F could not be held, a second batch of fish was genotyped etc. Compared with the genotyping of all selection candidates (1000, 5000 or 10 000), the use of batches saves genotyping costs. The results show that two batches of 50 fish were often necessary. With a batch size of 100, genetic level was 76-92% of the genetic level achieved for schemes with all fish being genotyped and thus candidates for the optimum contribution selection step. More parents were selected for schemes with larger batches, resulting in a higher genetic gain, especially when all selection candidates were genotyped. There was little extra genetic gain in genotyping of 1000 fish instead of 100 for the larger schemes of 5000 and 10 000 candidates. The accuracy of breeding values was similar for all batch sizes (∼0.30), but higher (∼0.5) when all candidates were included. Since only the phenotypically most superior fish were genotyped, BLUP-EBV were biased. Compared with genotyping of all selection candidates, the use of batches saves genotyping costs, while simultaneously maintaining high genetic gains. fish breeding / selection / parentage testing / walk-back selection / genetic markers

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Dynamic selection procedures for constrained inbreeding and their consequences for pedigree development

Cited by 153 publications

References 14 publications

Management of genetic diversity in small farm animal populations

Management of genetic diversity in small farm animal populations

Mating animals by minimising the covariance between ancestral contributions generates less inbreeding without compromising genetic gain in breeding schemes with truncation selection

A combination of walk-back and optimum contribution selection in fish: a simulation study

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