A New Era Begins as DNA Replaces Blood Typing

(Editor’s Note: At press time, the exact timing of the switch to DNA was uncertain.  AGA expects to make the conversion to DNA sometime later this summer. If you have an animal that needs to be tested, please contact the AGA.)

 

The AGA Board of Directors, at their January 2002 meeting, authorized the staff to make the conversion from blood typing to DNA testing for parent verification. Because DNA testing provides significant cost savings, powerful accuracy and simplified sample requirements, DNA has replaced blood typing as the standard method used by livestock associations for parent verification.

 

Animals That Must be Tested

Animals that have previously been tested are not required to be re-tested unless those animals are needed for parent verification purposes.  None of the AGA rules have been changed with regard to which animals must be tested and what tests are required.  As a reminder, AGA requires the following animals to be tested:

•   A.I. Sires – Must be DNA parent verified (requires that a DNA profile be on file for the A.I. sire plus its sire and dam)

•   Donor Dams – Must be DNA tested (requires that a DNA profile be on file for the Donor Dam only)

•   Foreign or Imported Animals – Must be DNA tested (requires that a DNA profile be on file for the imported animal only)

•   24-Day Rule: all registered offspring resulting from matings where the dam was exposed to more than one sire within 24 days, either A.I. or natural service – Must be DNA sire verified (requires that a DNA profile be on file for the animal in question plus its sire)

•   Randomly Selected Animals – AGA requires that approximately every 300th registered female be parent verified (requires that a DNA profile be on file for the randomly selected animal plus its sire and dam).

 

Timing

In order to make the transition to DNA as simple as possible, all new animals that require testing must fulfill their testing requirements completely using DNA.  Blood typing results and DNA results are not comparable.  In other words, if you have a DNA profile of calf and blood typing profile of its parent, parentage cannot be verified.  Therefore, if a new animal requires parent verification, all three animals must have a DNA test on file.  Unfortunately, this will require that some animals that were previously blood typed be re-tested using DNA.  The AGA has arranged to have the 150 most heaviest used A.I. sires over the last 5 years be DNA tested initially.  This should help reduce the financial burden of re-testing a large majority of animals.

 

DNA Testing Costs

AGA has negotiated lower fees for DNA testing as compared to blood typing.  Because some animals will be required to be re-tested, DNA tests will be performed at a temporarily reduced price of $25 per test for the first twelve months.  In other words during the first 12 months of testing, you can perform 2 DNA test ($25 x 2 = $50) for nearly the same cost as a single blood typing test ($45).  After the initial 12 months, the DNA fee will be $35 per test ($10 less than the current cost of blood typing).

 

Simplified Sample Collection

Another significant advantage of DNA testing as compared to blood typing is the ease of sample collection.  Unlike blood typing where a blood sample had to be pulled from the animal, almost any tissue sample works for DNA including hair, semen or blood.  The preferred DNA sample is hair.  Collecting a hair sample is as easy as pulling 20 to 25 hairs (roots must be attached) from the switch of an animal’s tail, taping the hair to the center of the appropriate DNA kit (see DNA Kit), folding the DNA Kit and placing into a regular envelope and mailing the official hair kit by regular mail to the DNA laboratory.

 

Step by Step Procedure

1. Animal must be recorded at the AGA (compute or register)

2. Request an “official” DNA Hair Kit for each animal

3. Collect a Hair Sample (20-25 hairs)

4. Tape the Hair Sample to the “official” DNA Hair Kit—samples will NOT be accepted unless they are attached to the “official” AGA hair kit

5. Fold the DNA Hair Kit and Place into a standard envelope—only one sample per envelope please

6. Mail directly to the offical DNA lab via regular U.S. mail

7. Results should be returned in 10 to 20 business days

 

Interpreting DNA Results

DNA results are fairly easy to interpret.  The DNA testing method uses 15 primary markers to evaluate parentage validation.  Nine of the 15 markers are standard markers used by all the major breeds.  These standard 9 markers can determine parentage across breeds provided that we know their DNA profile.  The accuracy of using DNA is .999 or greater using the 15 primary markers.

 

Because we know that animals receive one marker from each parent, we can quickly evaluate the calf DNA profile to see if it contains a marker from each parent.  Study the first example below showing an animal that qualifies to both parents.  Specifically, look at the marker results for ETH 13.  The calf contains identical markers of 266.  By definition, this means that both parents must contain a 266 for the ETH 13 marker as is the case with this animal.  At marker BM 1824, the DNA profile includes 127/137.  Again, by definition, the calf must have received a 127 from one parent and a 137 from the other parent.  In this particular case, we know that the calf inherited the 127 from the sire and the 137 from the dam.

 

Now, analyze the second example below where that dam has been excluded.  Once again, study the DNA profile results for marker ETH 13.  The calf DNA profile contains 262/266.  The dam is excluded based on the fact that the calf DNA profile contains 262/266 and dam DNA profile does not contain a 262 or 266.  This is also the case at marker TGLA 48.  The dam contains 156 only and calf profile does not include a 156.  Therefore, the dam is excluded as the parent. 

 

You will also notice that the DNA profile of the calf shows incompatibility at markers BM 1824, ETH 10, SPS 115 and TGLA 53.  In all of these cases, both parents possess one of the allowable markers but one marker is unaccounted for.  As an example, look at the profiles for marker BM 1824.  The calf profile is 135/137.  Both parents contain a 137 but neither contains a 135.  Therefore, we know that one parent is not accurate.  Based on markers ETH 13 and TGLA 48 we know that the dam has been excluded and is the likely culprit.

 

Summary

The movement from blood typing to DNA testing will provide the AGA membership with a powerful, simplified and cost-effective method for parental verification.  If you have any questions or comments with regard to DNA, please don’t hesitate to contact the AGA.  We are confident you will appreciate the simplification that DNA testing provides.

 

1. Calf QUALIFIES to Both Sire and Dam

 

 

 

 

 

SIRE

CALF

DAM

Case Number

GV2002008001

GV2002008002

GV2002008002

Registration

AMGV 123456

AMGV 782598

AMGV 657895

Prefix + Tattoo

DONS 11A

BEEF 54L

BEEF 32K

ETH 13

266/270

266

264/266

EHT 225

180/184

184

184/190

BM 1824

127/141

127/137

127/137

TGLA 126

187/198

198

190/198

TGLA 122

218

218

218/224

TGLA 227

140/150

146/150

146/154

BM 2113

117

117

117

ETH 10

208/224

204/224

204/208

SPS 115

90

90

90/92

INRA 23

246/258

246/258

246/254

TGLA 53

149/153

153

153/181

CYP 21

119/127

119

119

BM 1818

84/88

88/92

80/92

RM 067

75

75/77

77

TGLA 48

164/182

156/164

152/156

* a single number indicates that the animal contains the identical markers

 

 

 

 

Summary:

 

 

 

*All Markers demonstrate compatibility

 

*Both Sire and Dam Qualify

 

 

 

 

 

2. Calf EXCLUDED to Dam

 

 

 

 

 

 

SIRE

CALF

DAM

Case Number

GV2002009001

GV2002009002

GV2002009002

Registration

AMGV 256894

AMGV 782599

AMGV 657355

Prefix + Tattoo

DONS 22A

BEEF 58L

BEEF 67K

ETH 13

262/264

262/266

264

EHT 225

180/184

180/184

180/184

BM 1824

127/137

135/137

133/137

TGLA 126

190/198

187/190

187/198

TGLA 122

218

218

218

TGLA 227

140/148

140/148

144/148

BM 2113

123/125

123/125

117/125

ETH 10

202/208

208/220

202/208

SPS 115

90

90/94

90/98

INRA 23

246

246

246/254

TGLA 53

153

145/153

153

CYP 21

119/121

119/121

119/121

BM 1818

92

92

84/92

RM 067

77

75/77

75/77

TGLA 48

152/162

152/164

156

Note: a single number indicates that the animal contains identical markers

 

 

 

 

Summary:

 

 

 

*Markers ETH 13, BM 1824, ETH 10, SPS 115, TGLA 53, TGLA demonstrates

    incompatibility with the DNA profiles of the sire and dam.

*Dam is excluded based on Markers ETH 13 and TGLA 48