J. Anim Sci.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Siewerdt, F.
Right arrow Articles by Parker, I. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Siewerdt, F.
Right arrow Articles by Parker, I. J.

Journal of Animal Science, Vol 78, Issue 4 832-845, Copyright © 2000 by American Society of Animal Science

JOURNAL ARTICLE

Response to 13 generations of selection for increased 8-week body weight in lines of mice carrying a sheep growth hormone-based transgene

F. Siewerdt, E. J. Eisen, J. D. Murray and I. J. Parker
Department of Animal Science, North Carolina State University, Raleigh 27695, USA.

The purpose of this study was to evaluate selection in lines of transgenic mice. Two replicates of lines that either carried or did not carry the sheep metallothionein-1a sheep growth hormone transgene (oMt1a-oGH) were established. The host lines had been previously selected for rapid growth or selected randomly. Within-litter selection for increased 8-wk body weight was carried out for 13 generations. The frequency of oMt1a-oGH was monitored in all generations in the transgenic lines, but no genotypic information regarding the transgene was used as an aid to selection. The oMt1a-oGH was activated from weaning, at 3 wk, until 8 wk of age by adding ZnSO4 to the drinking water. Zinc stimulation of the transgene was not done during mating, gestation, or lactation. Data on body weights and weight gains were analyzed with a conventional mixed model and with an animal model. Genetic progress was achieved in all lines subjected to directional selection. In the control background, response to selection for 8-wk body weight was larger in the nontransgenic lines than in the transgenic lines, whereas no difference was found in the selected background. The frequency of the transgene was increased from the initial .5 to .62 in the randomly selected background but decreased to .04 in lines from a selected background. The REML estimates of variance components and genetic gain estimates varied greatly between the two methods. In general, there was better agreement between the realized heritability estimates and the heritability estimates obtained from the conventional mixed model analysis than between realized heritability estimates and results obtained using the animal model. Favorable correlated responses were obtained for 3- and 6-wk body weights and on 3- to 6- and 6- to 8-wk weight gains. Correlated responses to selection were larger in the selected than in the nonselected background but were not affected by the presence of the transgene. Results suggest that constructs similar to the oMt1a-oGH, which allow tight regulation, may be successfully incorporated into commercial livestock and should have larger effects in populations that have not been subject to selection.


This article has been cited by other articles:


Home page
 J ANIM SCIHome page
N. R. Adams, J. R. Briegel, and K. A. Ward
The impact of a transgene for ovine growth hormone on the performance of two breeds of sheep
J Anim Sci, September 1, 2002; 80(9): 2325 - 2333.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2000 by the American Society of Animal Science.