Scientists from Texas AgriLife Research and the Texas A&M University College of Veterinary Medicine & Biomedical Sciences (CVM) are part of a consortium of researchers who have developed an annotated sequence of the cattle genome which could lead to better disease resistance and higher quality meat for consumers, the researchers say.
Their work was led by the Baylor College of Medicine Human Genome Sequencing Center and published in two reports that appear in the journal Science.
The researchers used the complete sequence from a single Hereford cow and comparative genome sequences for six more breeds, looking for changes called single nucleotide polymorphisms – SNPs – markers that can help researchers identify favorable traits.
"The biggest thing that came out of the SNP project was the resource of the SNPs themselves," said Dr. Clare Gill, a Texas AgriLife Research beef geneticist who co-led the SNP initiative. "That has changed how we operate when we do DNA studies and identification of genes."
Texas AgriLife Research is part of the Texas A&M University System, with scientists based at Texas A&M in College Station and 13 research centers across the state.
SNPs in 497 cattle from 17 geographically and biologically diverse breeds and two related species (anoa and water buffalo) were used in the project. Using SNPs, Gill said there could be considerable progress made in cattle health as well as meat production.
"There could be progress made in disease resistance, production efficiency, tenderness and marbling," Gill said.
Dr. James Womack, who holds the title of Distinguished Professor in the CVM and has studied the bovine genome for the past 20 years and is one of the team leaders of the project, said the work "opens the door to look at all sorts of specific interests in cattle – from disease immunity to better meat quality, better milk production and on and on."
"Ten to 20 years down the line, this will lead to new avenues in cattle research that were not available to us previously," Womack says. "It's a huge step in the field of cattle research."
His colleague in much of the work was Dr. Loren Skow, also a faculty member in the CVM.
Gill hosted the DNA repository from cattle around the world. Gill is using the SNP resources generated in this study to tie information into the agency's own cattle mapping resource at the AgriLife Research Center in McGregor.
Gill also led a team that annotated the genes detailed in "Science" and received contributions from students in her applied animal genomics graduate-level course. Contributing to the research were graduate students Carl Muntean, Cody Gladney, Natasha Romero and Jungwoo Choi. Undergraduates Clayton Boldt and Jennifer Chapin contributed annotations, as well as Kris Wunderlich (doctoral candidate) and Colette Abbey (research associate). AgriLife Research scientists Drs. Penny Riggs and Tom Welsh also contributed to the annotation process.
Womack said the cattle sequence took six years to complete, annotate and analyze with more than 300 scientists from 25 countries. Most of more than 25 companion reports describing detailed analyses of the two projects by the Bovine Sequencing Project and the Bovine Hapmap Consortia appear online at http://www.biomedcentral.com in a special electronic issue of the BioMed Central journal group.
"The future challenge will be to explore the bovine genome sequence in greater depth to fully understand the genetic basis of the evolutionary success of ruminants as this will provide opportunities to address some of the crucial issues of the present time – efficient and sustainable food production for a rapidly increasing human population," said Dr. Richard Gibbs, director of the BCM Human Genome Sequencing Center and principal investigator on the project.
The authors concluded that the bovine genome, consisting of at least 22,000 genes, is more similar to that of humans than that of mice or rats. They note that most cattle chromosomes correspond to part or all of human chromosomes, although the DNA is rearranged in some areas.
The project was funded by several groups and agencies, among them the Kleberg Foundation, the State of Texas, the National Human Genome Research Institute and the U.S. Department of Agriculture.
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