Researchers at The Institute for Genomic Research (TIGR) and The Center for the Advancement of Genomics (TCAG) have sequenced and analyzed 1.5X coverage of the dog genome.
The research, published in the September 26th issue of the journal Science, asserts that a new method of genomic sequencing, partial shotgun sequencing, is a cost-effective and efficient method to sequence and analyze many more large eukaryotic genomes now that there are a number of reference genomes available with which to compare. This important new study was funded by the J. Craig Venter Science Foundation.
The TIGR/TCAG team assembled 6.22 million sequences of dog DNA for nearly 80% coverage of the genome. Comparing the dog sequence data with current drafts of the human and mouse genome sequences showed that the dog lineage was the first to diverge from the common ancestor of the three species and that the human and dog are much more similar to each other at the genetic level than to the mouse. The group also identified 974,400 single nucleotide polymorphisms (SNPs) in the dog. These genetic variations are important in understanding the genes that contribute to diseases and traits among various breeds of dogs.
The dog genome sequencing project, led by Ewen Kirkness, Ph.D., investigator at TIGR, revealed that more than 25% or 650 million base pairs of DNA overlap between human and dog. The sequence data was used to identify an equivalent dog gene for 75% of known human genes. In addition to this core set of common genes, the sequence data has revealed several hundred gene families that have expanded or contracted since divergence of the dog lineage from our common ancestor. For example, the dog genome is predicted to encode a much greater diversity of olfactory receptors than we find in human - which may contribute to their keen sense of smell.
“In little more than a decade genomics has advanced greatly and we now have approximately 150 completed genomes, including the human, mouse and fruit fly, in the public domain,” said J. Craig Venter, Ph.D., president, TCAG. “With each sequenced genome the level of information gleaned through comparative genomics is invaluable to our understanding of human biology, evolution, and basic science research. Our new method is an efficient and effective way of sequencing that will allow more organisms to be analyzed while still providing significant information.”
Conservation of the dog and human genome sequences is not restricted to genes, but includes an equally large fraction of the genomes for which functions are not yet known. "Understanding why these sequences are so highly conserved in different species after millions of years of divergent evolution is now one of the most important challenges for mammalian biologists," says Kirkness.
The Institute for Genomic Research (TIGR), which sequenced the first complete genome of a free-living organism in 1995, is a not-for-profit research institute based in Rockville, Maryland. TIGR conducts research involving the structural, functional, and comparative analysis of genomes and gene products in viruses, bacteria, archaea, and eukaryotes.
The Center for the Advancement of Genomics (TCAG) is a not-for-profit genomics policy and research center dedicated to advancing science and medicine through education and enlightenment of the general public, elected officials, and students. TCAG will seek to better understand evolutionary issues, broad social and ethical issues such as race as a social concept rather than a scientific one, and combating genetic discrimination. TCAG will also focus on the public issues associated with biology/genomics in mitigating greenhouse gas concentrations and biological energy production. TCAG is a 501 (c) (3) organization.
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