Recognized: October 7, 2020
WHAT ARE SCRAPIE RESISTANCE VARIANTS?
Natural occurring mutations in the prion protein gene (PRNP) of goats have been identified which confer resistance to scrapie. The S146 and K222 variants have been confirmed to confer genetic resistance against classical scrapie. These variants are named for the amino acid changes in the PRNP protein (PrPC): S146 indicates presents of a serine (S) at position 146 instead of an asparagine (N) and K222 indicates a lysine (K) at position 222 instead of a glutamine (Q). S146 and K222 forms of PrPC are more resistant to conversion to the abnormal PrPSc, which results in the development of clinical scrapie.
RATIONALE FOR POLICY
Identification of animals possessing the mutations associated with scrapie resistance in breeding stock will allow the breeder to formulate breeding and selection programs targeted towards development of scrapie resistant herds. Traditionally control of scrapie in both sheep and goats has been through whole herd depopulation. Animals identified as having a resistant variant may not be subject to euthanasia/depopulation in the case of scrapie positive herd mates. ADGA offers scrapie variant testing and recording to members and the wider goat community.
ADGA will maintain a list of approved testing laboratories, and that information as well as forms and instructions for sample submission will be provided upon request.
Upon receipt of testing results from an approved laboratory, ADGA will maintain a database of scrapie variant testing results.
A report would appear as follows along with Animal information:
SCRAPIE VARIANT TESTING RESULT:
| Genetic Resistance Interpretation | 146 | 222 |
| No resistance to classical scrapie | NN | |
| One copy of protective variant K222, increased resistance to classical scrapie | NN | QK |
| Two copies of protective variant K222, increased resistance to classical scrapie | NN | KK |
| One copy of protective variant S146, increased resistance to classical scrapie | NS | |
| Two copies of protective variant S146, increased resistance to classical scrapie | SS | |
| One copy of each of S146 and K22 protective variants, increased resistance to classical scrapie | NS | QK |
As with all DNA information contracted through ADGA, ADGA retains proprietary rights to the results of scrapie variant testing for each animal. Samples submitted for analysis of scrapie variant testing status through the ADGA shall become the property of the contract laboratory upon receipt and may be used for general research purposes. Persons submitting samples for scrapie variant testing through the ADGA agree to indemnify and hold the ADGA harmless against any losses, costs or damages, including attorney fees arising from the results of the performed tests.
Test results for scrapie variant testing can be included in the ADGA database upon submission of paperwork confirming test results issued by the laboratory that conducted the test along with payment of the data transfer fee. Information provided by the laboratory must include the animal’s registration number, OR breed, gender, date of birth and tattoo information in addition to test results.
Upon the breeder’s request, this information may also be included in the animal’s permanent record as outlined above. A processing fee as well as the standard fee for certificate revision shall apply.