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Development of a synthetic pig sire line by election with immigration 2. Immigration

Published online by Cambridge University Press:  02 September 2010

A. J. Webb
A. J. Webb
Affiliation:
ARC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
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Summary

A synthetic sire line has been developed over 11 generations by a process of selection accompanied by immigration. In each generation prospective immigrants of any breed were mated to native pigs already i n the Sire Line, and, ignoring breed, their progeny were given the same opportunity of being selected as the progeny from matings involving natives alone. This method of immigration is shown to be biased as a result of (a) heterosis in crosses of immigrants with natives, and (b) treating natives and immigrants as if they were members of the same population. When affected by both sources of bias, the breeding values of inferior immigrant progeny may be seriously overestimated with the result that inferior genes may enter the native population and hold back genetic progress. Methods of removing the bias and alternative systems of immigration are discussed.

Type
Research Article
Information
Animal Production , Volume 22 , Issue 2 , April 1976 , pp. 245 - 254
Copyright
Copyright © British Society of Animal Science 1976

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References

REFERENCES

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