Long-term selection experiments provide a valuable resource for understanding the genetic changes that take place in animal improvement programs. The Virginia chicken lines have for more than 50 years been subjected to single-trait, bi-directional, divergent selection for high and low juvenile body weight. It is one of the most well studied experimental populations in agricultural animals and has played an instrumental role in the understanding of the genetic basis of complex traits. In this paper, we summarize the findings from the more recent publications focusing on the efforts to identify the loci contributing to selection response as well as discuss the currently ongoing research. We conclude by describing some future research prospects that promise to bring new, interesting insights into the biology of complex traits in the near future and their implications for future animal improvement programs.
body weight; chicken; epistasis; metabolic; QTL; selection
