A model describing how change in gene neighborhood might contribute to expression divergence. The genetic material is shown as a curly orange object and as a black line. The gene of interest is shown as a circle and box in green color. Neighbors of the gene, which are conserved between two species, are shown as red circles and boxes. The new neighbors of the gene upon incorporation into a new neighborhood are shown as blue circles and boxes. If the neighborhood of a gene is altered in one species relative to the other (and vice versa), the gene is likely to experience a different transcriptional environment. We postulate that an altered transcriptional environment is likely to lead to expression divergence between species. This may also result in a spectrum of phenotypic consequences, ranging from deleterious to neutral or advantageous upon which natural selection can operate.
