( ics Branch. “Nearly all of what we lear...)Researchers identify gene involved in dog size

In addition to Ostrander and her colleagues at NHGRI, the team included researchers from Cornell University in Ithaca, N.Y.; the University of Utah in Salt Lake City; the University of California, Los Angeles; the University of Southern California in Los Angeles; the University of Missouri in Columbia; the Waltham Centre for Pet Nutrition in Leicestershire, England; and the Nestle Research Center in St. Louis. Postdoctoral Fellow Nathan B. Sutter, Ph.D. from NHGRI’s Cancer Genetics Branch, served as lead author.

“By learning how genes control body size in dogs, we are apt to learn something about how skeletal body size is genetically programmed in humans. We also will increase our data set of genes likely to play a role in diseases such as cancer, in which regulation of cell growth has been lost,?said Ostrander, noting that the role of the IGF-1 gene family in prostate cancer susceptibility has already been well established.

Building upon previous research showing that the IGF-1 gene plays an important role in growth, body size and longevity in mice, the dog researchers used physical observations, X-ray imaging and DNA sequencing and genotyping analysis to study Portuguese water dogs—a breed that has an unusually wide range of skeletal size—as well as several small and large canine breeds. This analysis revealed that differences in dog body size appeared to be associated with minute genetic variations, referred to as single nucleotide polymorphisms (SNPs), in the IGF-1 gene. Researchers then narrowed the field of SNPs associated with small size by SNP genotyping in and around the IGF-1 gene in 463 Portuguese water dogs. A similar analysis was done using 526 dogs from 14 small breeds and nine giant dog breeds.

Ultimately, the researchers analyzed DNA fro
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Source:NIH/National Human Genome Research Institute