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Estimation of the dominance merit in noninbred populations without recourse to its inverted relationship matrix

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Chalh A., El_ G. M.

Journal of Applied Genetics

2003

vol. 44

issue 1

63-69

This study presents a new approach to obtain dominance estimates without using the full Henderson?s mixed model equations (MMEs) related to an additive plus dominance animal model. This reduction could decrease substantially the computing time and hence its cost. In contrast to a procedure that we proposed before, the method developed in this paper does not require D?1 and provides best linear unbiased prediction (BLUP) of genetic values that is close to that given by processing the full MMEs. In the previous study, we also elaborated an algorithm (denoted ?-REML) in order to approximate restricted maximum likelihood estimation of variance components via the expectation maximization (EM) algorithm. The ?-REML algorithm has been modified to be adapted to our new resolution approach. Through a numerical example, we show that there is a good agreement between REML-(EM), ?-REML and modified ?-REML estimates and that the latter algorithm is more efficient than our first proposition in terms of computing time and memory conservation.

Generating data in models including direct and maternal dominance effects

100%

Duangjinda M., Misztal I., Bertrand J. K.

issue 2

193-203

Algorithms are presented to simulate multiple generations of animal data by a model including direct additive genetic, maternal additive genetic, direct dominance, maternal dominance and permanent environmental effects. Dominance effects were computed as parental subclasses. Testing involved five single trait models that included direct contemporary group and direct additive effects, and different combinations of maternal, permanent environmental, and dominance effects. Simulated populations included 5 generations of animals and 20 contemporary groups per generation. The base population contained 200 sires and 600 dams. Variance components were estimated by Average-Information Restricted Maximum Likelihood (AIREML). No significant bias was observed. The simulation algorithms can be used in research involving dominance models, such as evaluation of mating systems exploiting special combining abilities of prospective parents.

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2 Journal of Applied Genetics

1 2003

1 2001

1 Bertrand J. K.

1 Chalh A.

1 Duangjinda M.

1 El_ G. M.

1 Misztal I.

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Estimation of the dominance merit in noninbred populations without recourse to its inverted relationship matrix

Generating data in models including direct and maternal dominance effects