Bovine genome sequencing provides clues to possible new developments
Scientists from Texas AgriLife Research and Texas A&M University's College of Veterinary Medicine Biomedical Sciences are part of a consortium of researchers who've developed a "first draft" sequence of the cattle genome.
The findings could lead to such future developments as disease-resistant cattle, improved production efficiency and more tender beef, researchers say. The work was led by 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, an 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."
SNPs in 497 cattle from 19 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, a distinguished professor in Texas A&M's College of Veterinary Medicine and Biomedical Sciences, has studied the bovine genome for the past 20 years.
Womack, who was 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," he said. "It's a huge step in the field of cattle research."
Womack's colleague in much of the work was Dr. Loren Skow, also a faculty member in the College of Veterinary Medicine.
Gill hosted the DNA repository collected from cattle around the world. She 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 at McGregor.
Gill also led a team that annotated genes detailed in Science and received contributions from her students in the applied animal genomics graduate studies course.
Contributing to the research were Texas A&M graduate students Carl Muntean, Cody Gladney, Natasha Romero and Jungwoo Choi. Undergraduates Clayton Boldt and Jennifer Chapin contributed annotations, as did doctoral candidates Michael Dickens and Kris Wunderlich and research assistant Colette Abbey. AgriLife Research scientists Drs. Penny Riggs and Tom Welsh also contributed to the annotation process.
The cattle sequence took six years to complete, annotate and analyze, and involved 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 will appear online at 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. 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.