Scientists Work on Sequencing of Cattle Genome

An international consortium of French, Canadian, and US scientists have begun work on a sequence-ready map that will enable them to quickly and efficiently sequence the entire cattle genome.

The scientists will create a sequence-ready bacterial artificial chromosome (BAC) map and anchor it to the humane genome map by reference points called comparatively-anchored sequence tagged sites, or CASTS. Constructing the map will proceed in three phases. First, all 280,000 clones of a BAC library produced by a laboratory at the Children's Hospital Oakland Research Institute (CHOR, CA, USA) will be fingerprinted by a group at the British Columbia Cancer Agency (BCCA, Canada). Second, sequencing of the ends of at least 100,000 fingerprinted BAC-clones will be done by a team at the University of Illinois (Champaign, USA) and The Institute for Genomic Research (TIGRE, Rockville, MD, USA).

The sequence-ready BAC map will be created by merging the BAC fingerprints with the BAC-end sequence data. The entire array of cattle BAC clones, called contigs, will be scaffolded on to specific cattle chromosomes using a bioinformatics tool called COMPASS. The assignment of contigs to cattle chromosomes will be based on a whole-genome cattle-human comparative gene map. Reciprocal exchange of BAC fingerprinted and end-sequenced clones with other scientists will be used to create a thorough sequence-ready map.

To date, more than 125,000 cattle BAC clones have been fingerprinted and more than 2,000 BAC end-sequences have been produced. Once this stage is completed, a new consortium will produce a draft sequence of the entire cattle genome. This sequencing will help scientists understand the evolution of mammalian genomes and provide powerful new tools for animal breeding and securing the safety of the world's supply of meat and milk.

"Already, the research has shown that sequenced cattle DNA can be more valuable than sequenced mouse or rate genomic DNA is predicting the locations of evolutionarily conserved noncoding gene regulatory elements,” said Harris Lewin, a professor of animal sciences at the University of Illinois who is helping to coordinate the project.




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