Changes in traits across generations depend on selection of heritable differences between individuals. Theory predicts that heritable differences between individuals will be reduced in small populations over time, limiting future adaptation, when gene-effects are independent of each other. However, when the effects of genes change depending on what other genes are present in the individual this loss of heritable variation may be limited. The investigators will examine changes in heritable variation over generations in a series of forty small experimental mouse populations derived from the cross of inbred strains. They had previously identified loci affecting body weight, fatpad weight, and tail length in these populations and found that the expected loss of heritable variance did not occur. The investigators will measure the genotypes at these loci and their contributions to heritable variance, identifying how context-dependent gene-effects prevent the loss of heritable variation in small populations.
This research is important for understanding the genetic bases of species formation and adaptation in small populations. It has important implications for conservation of small populations and their ability to adapt to new circumstances. The context-dependent nature of gene-effects also has important consequences for our understanding of the genetic bases of complex diseases.
