The size, shape, and behavior of the modern domesticated dog has been sculpted by artificial selection for at least 14,000 years. The genetic substrates of selective breeding, however, remain largely unknown. Here, we describe a genome-wide scan for selection in 275 dogs from 10 phenotypically diverse breeds that were genotyped for over 21,000 autosomal SNPs. We identified 155 genomic regions that possess strong signatures of recent selection and contain candidate genes for phenotypes that vary most conspicuously among breeds, including size, coat color and texture, behavior, skeletal morphology, and physiology. In addition, we demonstrate a significant association between HAS2 and skin wrinkling in the Shar-Pei, and provide evidence that regulatory evolution has played a prominent role in the phenotypic diversification of modern dog breeds. Our results provide a first-generation map of selection in the dog, illustrate how such maps can rapidly inform the genetic basis of canine phenotypic variation, and provide a framework for delineating the mechanistic basis of how artificial selection promotes rapid and pronounced phenotypic evolution.

We describe a system that permits the automated analysis of reporter gene expression in Caenorhabditis elegans with cellular resolution continuously during embryogenesis. We demonstrate its utility by defining the expression patterns of reporters for several embryonically expressed transcription factors. The invariant cell lineage permits the automated alignment of multiple expression profiles, allowing direct comparison of the expression of different genes' reporters. We also used this system to monitor perturbations to normal development involving changes both in cell-division timing and in cell fate. Systematic application of this system could reveal the gene activity of each cell throughout development.

Both sexually dimorphic and core sensory neurons are normally required in the adult for sexual attraction, but they can replace each other during sexual maturation if necessary to generate robust male-specific sexual attraction behavior.