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Combining microsatellite and pedigree data to estimate relationships among Skyros ponies

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Bomcke E., Gengler N.

Journal of Applied Genetics

2009

vol. 50

issue 2

133-143

The main objective of this study was to develop a new method to estimate relationship coefficients by combining molecular with pedigree data, which is useful for specific situations where neither pedigree nor molecular data are complete. The developed method was applied to contribute to the conservation of the Skyros pony breed, which consists of less than 200 individuals, divided into 3 main herds or subpopulations. In this study, relationships between individuals were estimated using traditional estimators as well as the newly developed method. For this purpose, 99 Skyros ponies were genotyped at 16 microsatellite loci. It appeared that the limitation of the most common molecular-based estimators is the use of weights that assume relationships equal to 0. The results showed that, as a consequence of this limitation, negative relationship values can be obtained in small inbred populations, for example. By contrast, the combined estimator gave no negative values. Using principal component analysis, the combined estimator also enabled a better graphic differentiation between the 3 subpopulations defined previously. In conclusion, this new estimator can be a promising alternative to traditionally used estimators, especially in inbred populations, with both incomplete pedigree and molecular information.

Inbreeding and relationship in Polish Black-and-White sires

100%

Kania-Gierdziewicz J.

Journal of Applied Genetics

2005

vol. 46

issue 2

187-193

The aim of the study was to analyse inbreeding and relationship in the Polish population of Black-and-White sires. Data were pedigrees of 25 036 Black-and-White sires born from 1960 through 2000, divided into subsets of 11 447 proven and 13 589 unproven sires, and their 38 228 ancestors, altogether 63 264 animals. Average inbreeding coefficients were about 0.3% for both subsets of sires. Mean relationship coefficients ranged from 0.1% in all animals to 0.7% in the subset of proven sires. Positive time trends in inbreeding coefficients were observed when the subsets of sires were divided into 5-year intervals according to the year of birth and in terms of Holstein Friesian gene contribution. Key words: Black-and-White sires, inbreeding, relationship.

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2 Journal of Applied Genetics

1 2009

1 2005

1 Bomcke E.

1 Gengler N.

1 Kania-Gierdziewicz J.

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Combining microsatellite and pedigree data to estimate relationships among Skyros ponies

Inbreeding and relationship in Polish Black-and-White sires