Download Miniature Smooth- and Long-haired Dachshund PRA

PRA-prcd Testing for Labrador retrievers in South Africa
Inqaba Biotec was established in 2001 by South African, Swiss and American
scientists. The main service areas of this genetic laboratory are
oligonucleotide synthesis1 and DNA sequencing2. Our clients include
universities and other research institutions. Inqaba has since grown in leaps
and bounds and during 2009 expanded to provide animal genetic testing.
Canine genetic disease testing was the first area explored as there was no
local service provider. One of the tests offered is PRA-prcd, an eye disorder
that occurs in Labrador retrievers, amongst other breeds.
PRA-prcd is caused by a single base pair substitution3 in the PRCD gene4 on
the canine chromosome 95 and the mode of inheritance is autosomal
recessive6. This mutation alters the reading frame of the gene and could
ultimately lead to blindness. The test indicates the genetic profile of the gene
and classifies the dog as clear, carrier or affected for the causative mutation.
A clear dog carries no mutant copies of the gene, will not display the
symptoms of the disease and will not pass the mutant copy to its offspring. A
carrier dog has one copy of the mutant gene and one wild type7 copy. This
dog will not display the symptoms of the disease but may pass the mutant
copy to its offspring. The third category is affected dogs and these dogs have
a greater probability to display the symptoms of the disease (although not all
will go blind), and will pass the mutant copy to its offspring.
Breeders should utilize results of the genetic test as a tool to improve their
breeding lines. Preferably all mating should be performed between two clear
dogs. In the case that a dog is a carrier or affected for the causative mutation
but carries other desirable traits to be manifested in the continued breeding
line, different mating scenarios could be considered (refer to Table 1). For
Oligonucleotide synthesis is the chemical synthesis of relatively short fragments
of DNA with defined chemical structure (sequence). The technique is extremely
useful in laboratory practice as it provides a rapid and inexpensive access to custommade oligonucleotides of the desired sequence. (Ref: www.wikipedia.com)
2
DNA sequencing refers to sequencing methods for determining the order of the
nucleotide bases in a molecule of DNA. (Ref: www.wikipedia.com)
3
A mutation is the altering of the DNA sequence of a gene. The change in the
sequence can be due to an insertion of nucleotides, deletion of nucleotides or single
nucleotide substitutions.
4
A gene is the basic unit of heredity. Each animal has two copies of each gene, one
inherited from each parent. Different variants of a gene are called alleles. A gene is
always found on the exact same place on the same chromosome, and that place is
called a locus.
5
All DNA is packed into chromosomes. A dog has 39 chromosome pairs (one
chromosome of each pair inherited from each parent). 38 pairs are autosomal or
body chromosomes of which males and females have the same chromosomes. One
pair is called sex-chromosomes of which males have one X and one Y chromosome
and females have two X chromosomes.
6
Autosomal recessive means only one gene is involved and males and females are
affected equally.
7
The Wild type gene copy refers to the normal or healthy copy of the gene.
1
example, a dog that carries the PRA-prcd mutation with other desirable traits
could be mated to a clear dog and each puppy will have a 50% chance to be
clear and a 50% chance to be a carrier. These puppies should then be tested
and again be mated to clear animals and thereby leading to the subsequent
eradication of the mutation from the lines.
Table 1: Possible breeding scenarios
Parent 1 genotype
Clear
Parent 2 genotype
Normal
All Clear
Carrier
50% Clear
50% Carrier
Affected
All Carrier
Carrier
50% Clear
50% Carrier
25% Affected
25% Clear
50% Carrier
50% Carrier
50% Affected
Affected
All carriers
50% Carrier
50% Affected
All Affected
The price structure of the test is indicated in Table 2. When testing one or two
dogs the price is R456 (incl Vat) each, and we offer a 15% discount when
testing 3 – 7 dogs, and 30% discount when testing 8 or more dogs. We also
offer a courier service that will collect any number of samples from anywhere
in South Africa at a price of R57 (incl Vat).
Table 2: Price structure of the PRA-cord1 test
Number of dogs tested Price for each dog (incl VAT)
1 or 2
R456
3–7
R388
8 or more
R320
We offer two sampling methods. Firstly 1-2 ml whole blood can be collected
by the owner’s veterinarian and sent to us via courier. We can arrange the
courier to collect the sample from the veterinarian’s practise. The second
method is the use of FTA filter papers. We send the owner the papers
together with a needle and full instructions via registered post. The owner can
take the sample themselves. The dog’s ear is pricked and one or two drops of
blood are blotted on the paper. The paper is then sent back to us via mail or
courier.
For more information please don’t hesitate to contact Henriëtte van der Zwan
from Inqaba biotec.
E-mail: [email protected]
Tel: 012 343 5829 or 018 290 6926
Cell: 082 859 2229
Fax: 012 343 0287 or 018 290 6926
Website: www.inqababiotec.co.za