Genebank development for the conservation of livestock genetic resources in the United States of America

摘要

The USDA established the National Animal Germplasm Program (NAGP) to conserve livestock genetic resources in 1999. The NAGP is primarily concerned with the development of cryopreserved germplasm and tissue samples from U.S. livestock species. To execute the program's mission, subcomponents dealing with genetic diversity, cryopreservation, and database development have been initiated. An early decision was made to develop collections on all U. S. livestock breeds. Since that decision, collections on119 breeds have been initiated and ten of the collections have reached the collection goal. An example of selecting animals for the collection is given using Jersey cattle. The selection procedure utilizes the coefficient of genetic relationship as a basis to cluster candidates for the collection and as a method for assessing how complete a breed's collection may be. By using this approach it was determined that 86% of the clusters were presently represented in the collection. With this information collection efforts could be planned to fill in the missing gaps. Performance information from a sample of the in-situ population and the collection were compared. This analysis indicated that there were no significant differences between the means for the Core Collection and the in-situ population sample for milk production, milk protein and net merit index. A significant difference was found for milk fat. While the total collection effort is not complete, samples have been distributed from the repositoryto perform QTL and genetic distancing studies, creation of a research population, and to introduce genetic variation into a rare cattle breed. Progress has been made in starting breed collections however, significant efforts are needed to: acquire additional accessions for the collection, develop the information system, and quantify levels of genetic diversity within and among breeds.