anyone know of any whitetail research for codons of PrP to select cwd resistant animals ??
from what I have found there are 3 different codons they talk about 96,153,and 226.
Sheep
16px;serif"The good news is that there is a test
16px;serifavailable today that guarantees that a sheep
16px;serifdoes not have scrapie and will not acquire
16px;serifscrapie, even if exposed. That test is the
16px;serifcodon 171 test. The codon 171 test is a
16px;serifDNA test that determines the amino acid
16px;serif(building block of protein) in the 171
9.6px;serifst
16px;serifposition of the prion protein. The test
16px;serifdetermines the genotype of the codon ( a
16px;serifshort stretch of DNA that codes for a single
16px;serifamino acid) that codes for the 171
9.6px;serifst
16px;serifamino
16px;serifacid. If a sheep has an “R� amino acid at
16px;serifposition 171 it is “negative� for scrapie,
16px;serifwhich means that it does not have and will
16px;serifnever get scrapie. “R� actually stands for the
16px;serifamino acid arginine, but it is easiest to think
16px;serifof it as standing for resistance. Since sheep,
16px;seriflike humans, have chromosomes in pairs
16px;serif(one from the mother and one from the
16px;seriffather) they may be RR (both chromosomes
16px;serifwith the resistant gene), QR (one
16px;serifchromosome with the resistant gene) and
QQ (sensitive to scrapie)
16px;serifThe best news of all is that only one
16px;serif“R� gene is necessary to confer virtually
16px;serifcomplete resistance. No QR or RR sheep
16px;serifhas ever been confirmed to have scrapie in
16px;serifthe U.S. and no QR sheep has ever tested
16px;serifpositive in a third eyelid test. Recent work
16px;serifexamining placental tissue from QR lambs
16px;serifwhose dams (QQ) are affected with scrapie
16px;serifindicates that QR sheep cannot be carriers.
16px;serifRelative to third eyelid testing, DNA testing
16px;serifis simple (it uses only a small blood sample)
16px;serifand inexpensive and DNA does not change.
16px;serifA lamb that is RR will always be RR and
16px;serifwill, therefore, always be negative for
scrapie.
16px;serifPerhaps instead of calling for more
16px;serifresearch to develop more tests, we in the
16px;serifsheep industry should be calling for
16px;serifimplementation of rational scrapie programs
16px;serifbased on the science we already have. If a
16px;serifsmall fraction of the money spent to date on
16px;serifscrapie programs could instead have been
16px;serifused to subsidize producers to purchase RR
16px;seriframs, we could be well on our way to
16px;seriferadicating scrapie. Remember, every lamb
16px;seriffrom an RR ram will be at least QR and,
therefore, resistant to scrapie.
Elk Codon testing at UC Davis
Detailed CWD Information
CWD infection causes the normal cellular prion protein (PrP) to be converted to an abnormal form. This conversion of the PrP initiates the disease process. DNA sequencing of the PrP gene in elk has shown a single base difference at codon 132. This genetic difference among animals changes the amino acid from methionine to leucine and appears to affect susceptibility or incubation time of disease. Testing of elk for codon 132 of PrP may help breeders to select for animals that are less susceptible to CWD. Below is a summary of the results of the test and the susceptibility status.
class="Codon 132 Testing
Breeders should be aware that only 1% of the elk tested are L/L for codon 132.
Genotype
Description
M/M
2 copies of methionine = susceptible
L/M
1 copy of methionine and 1 copy of leucine = susceptible*
L/L
2 copies of leucine = resistant*
* Research findings suggest that L/M elk have a longer incubation period before clinical signs are evident
** Research findings suggest that L/L elk are resistant to CWD; there has been only one confirmed case of CWD in an animal that tested L/L
