Optimum contribution selection for conserved populations with historic migration

Wellmann, Robin; Hartwig, Sonja; Bennewitz, Jörn

doi:10.1186/1297-9686-44-34

Cited by 36 publications

(50 citation statements)

References 22 publications

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“…A number of authors (Bulmer, 1971;Silvela and Diez-Barra, 1985;Sánchez et al, 2003;Falconer and Mackay, 2004) have evaluated inbreeding in mating strategies considering selection based on BLUP EBV, while panmictic/random mating with phenotypic selection served as a basic scenario for comparison. As stated by Wellmann et al (2012), optimum contribution strategy by maximizing gene diversity could eventually lead to the extinction of local breeds with historical migration because increased gene diversity would be achieved by maximizing migrant contributions. As there was a historical migration in Pinzgau cattle in Slovakia, simulation was conducted based on purebred population data and closed population structure.…”

Section: Resultsmentioning

confidence: 99%

Influence of mating systems and selection intensity on the extent of inbreeding and genetic gain in the Slovak Pinzgau cattle

Kasarda¹,

Mészáros²,

Kadlečík³

et al. 2014

CZECH J ANIM SCI

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ABSTRACT:The aim of the present paper was to simulate the scenarios for a maximum avoidance of inbreeding (MAI) mating strategy, and compare it with a random mating alternative, with the main focus on inbreeding and development of the genetic gain. The parameters of the simulation were based on the structure of the Slovak Pinzgau active population of 2868 animals (930 purebred cows). The selection under a total merit index (TMI) was simulated, covering the milk, survival, and live weight breeding value estimation results. The heritability of TMI (h 2 = 0.09) was estimated using a REML single trait animal model. Alternatives assumed a closed population structure, fixed number of mating per parent, and equal use of sires in insemination. Animals in generation 0 were set as founders without pedigree information. In separate simulation runs, the number of sires of sires was set at 2, 4, 5 or 10 mated with 40 dams of sires in all cases. The sex ratio of the offspring was assumed to be 50/50 male/female. Twenty consecutive generations were simulated for both random and maximum avoidance of inbreeding mating, which resulted in a total of 8 scenarios. Significant positive differences in genetic gain were observed in the MAI mating system with 2 (0.74**), 4 (0.24**), 5 (0.13**) or 10 (0.09**) sires in comparison to random mating design. When using MAI, significantly lower inbreeding was observed with 2 (5.44**), 4 (3.18**), 5 (2.43**) or 10 (1.16**) sires. Simulation results showed that the use of a maximum avoidance of inbreeding mating strategy would lead to significantly decreased rates of inbreeding while maintaining suitable levels of genetic gain in the Slovak Pinzgau population.

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Section: Resultsmentioning

confidence: 99%

Influence of mating systems and selection intensity on the extent of inbreeding and genetic gain in the Slovak Pinzgau cattle

Kasarda¹,

Mészáros²,

Kadlečík³

et al. 2014

CZECH J ANIM SCI

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“…Table 1). The inbreeding coefficients (F) were estimated with the function "pedIn breeding" from the "optiSel" R-package [16], whereas the rates of inbreeding were calculated for each year as…”

Section: Animals and Phenotypesmentioning

confidence: 99%

“…The rate of inbreeding between year i and j ( i j F − ∆ ) was computed by the average of annual inbreeding rates [17]. The additive genetic relationship matrix was estimated with the function "make A" from R-package "optiSel" [16].…”

Section: Animals and Phenotypesmentioning

confidence: 99%

“…Different approaches and considerations were discussed by Meuwissen [3] for the purpose of breed conservation. These methods consisted of aspects of optimum contribution selection [8] [9], integrating life and cryoconservation schemes [10] [11], rotational breeding schemes [12], and the introduction of novel traits from conserved populations into commercial breeding populations [13] [14]. The latter approach implies that traits from conserved breeds can be introduced into commercial breeds by introgression and genomic selection.…”

Section: Introductionmentioning

confidence: 99%

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Implementation of Breed-Specific Traits for a Local Sheep Breed

Schäler¹,

Thaller²,

Hinrichs³

2018

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In recent decades, a considerable number of local breeds have been replaced by high-yielding breeds for reasons of profitability. Many local breeds are now threatened by extinction and the loss of their native genetic diversity. The need to conserve breeds and their genetic diversity has a major importance due to the necessity for genetic change within and between populations. Novel approaches have to be explored and extended to maintain this genetic diversity. The aim of this study was the identification and implementation of breed-specific traits for a small, local sheep breed in northern Germany. The data comprised pedigree information, estimated breeding values (EBVs) of several conventional traits, and phenotypic information from a field experiment for two novel traits: 1) average daily gain under extensive circumstances (ADG E ) and 2) ultrasonic measurements of muscle-fat ratio (UMFR). The experimental design included a dataset of 47 progeny from 14 pure-bred rams of German White-Headed Mutton (GWM). The methodical approach was divided into four parts: 1) the analysis of the breeding programme, 2) the identification of breed-specific traits, 3) the estimation and correlation of novel breeding values, and 4) the consequences of implementing these novel traits. Genetic parameters and correlations were conducted by applying linear mixed models. The estimates for the heritability (repeatability) were between 0.70 and 0.83 (0.42 and 0.46). The genetic correlation was positive (0.61) and in accordance with the phenotypic correlation (0.62). Average daily gain under intensive circumstances (ADG I ) was moderately positive correlated with muscularity (0.60), as opposed to ADG E , which was moderately negative correlated with muscularity (−0.68). The EBV of ADG E was also moderately positive correlated with UMFR (0.64). Genetic response for ADG E enhanced to values of 481.09 g/day, 639.97 g/day, >700 g/day and >850 g/day for different selection intensity scenarios. Corresponding rates of inbreeding were 1.4%, 2.7%, 5.1%, and 7.9% after 10 years of selection. Genetic response for UMFR increased to 0.92, 1.34, 2.41, and >2.75, whereas remaining rates of inbreeding increased to 1.1%, 2.2%, 5.1%, and 7.9%. ADG I and ADG E were tendentially negatively correlated (−0.11), which strengthen the assumption of a biased ADG I . ADG E has a positive influence on meat-quality aspects (UMFR). Optimal use of reference sires with predefined selection intensity achieves genetic response for ADG E and UMFR with simultaneously acceptable rates of inbreeding.

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“…Moreover, in cases for which the level of introgression was too high or uncontrolled during many generations, the method was relatively inefficient. In a study on the preservation of the genetic background of three cattle breeds, Wellmann et al [15] also used pedigree information. Although their objective was slightly different, the method constrained exogenous genetic contributions and reduced the probability of identity by descent in the offspring to comparable levels.…”

Section: Introductionmentioning

confidence: 99%

Advantages of using molecular coancestry in the removal of introgressed genetic material

Amador¹,

Fernández²,

Meuwissen

2013

Genet Sel Evol

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BackgroundWhen introgression of undesired exogenous genetic material occurs in a population intended to remain pure, actions are necessary to recover the original background. It has been shown that genome-wide information can replace pedigree information for different objectives and is a valuable tool in the fields of genetic conservation and breeding. In this simulation study, molecular information provided by 50 000 SNP was used to minimise the molecular coancestry between individuals of an admixed population and the foreign individuals that originally introgressed a native population in order to remove the exogenous DNA.ResultsThis management method, which detects the ‘purest’ individuals to be used as parents for the next generation, allowed recovery of the native genetic background to a great extent in all simulated scenarios. However, it also caused an increase in inbreeding larger than expected because of the lower number of individuals selected as parents and the higher coancestry between them. In scenarios involving several introgression events the method was more efficient than in those involving a single introgression event because part of the genetic information was mixed with the native genetic material for a shorter period.ConclusionsGenome-wide information can be used to identify the purest individuals via the minimisation of molecular coancestry between individuals of the admixed and exogenous populations. Removal of the undesired genetic material is more efficient with a molecular-based approach than with a pedigree-based approach.

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Optimum contribution selection for conserved populations with historic migration

Cited by 36 publications

References 22 publications

Influence of mating systems and selection intensity on the extent of inbreeding and genetic gain in the Slovak Pinzgau cattle

Influence of mating systems and selection intensity on the extent of inbreeding and genetic gain in the Slovak Pinzgau cattle

Implementation of Breed-Specific Traits for a Local Sheep Breed

Advantages of using molecular coancestry in the removal of introgressed genetic material

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