A2 Ghee
A2A2 Meaning: How A2 Milk & A2 Ghee Are Tested
A2A2 means an animal has inherited two copies of the A2 version of the beta-casein gene (CSN2), one from each parent, so its milk contains only A2 beta-casein. A1A2 animals give mixed milk and A1A1 animals give A1 milk. Genotype is confirmed with a PCR DNA test on hair, blood or milk — which is how a genuine A2 ghee claim is proven.
Quick take
- A2A2 = two A2 gene copies → milk with only A2 beta-casein.
- A1A2 = mixed milk; A1A1 = A1 milk.
- Proven by a PCR genotype test (e.g. TaqMan) on hair, blood or milk.
- The test is done on the animal or milk, not on the finished ghee.
A1A1, A1A2 and A2A2 explained
Every cow or buffalo carries two copies of the gene that codes for beta-casein, one of the main milk proteins. Each copy can be the A1 or A2 variant, giving three possible genotypes:
| Genotype | Milk contains | Typical animals |
|---|---|---|
| A2A2 | Only A2 beta-casein | Indian indigenous cows (Gir, Sahiwal, Rathi…), buffalo |
| A1A2 | A1 and A2 mixed | Many crossbred cows |
| A1A1 | Only A1 beta-casein | Common in Holstein Friesian and other European breeds |
Indigenous Indian breeds are generally A2A2, but decades of crossbreeding mean individual animals can differ — which is why testing matters. Background: A2 vs A1 ghee.
How A2 testing works
- Sample: a few hairs with roots, a blood sample or milk from the animal or herd.
- DNA extraction: the lab isolates DNA from the sample.
- PCR genotyping: methods such as TaqMan real-time PCR detect which beta-casein variants are present.
- Result: A1A1, A1A2 or A2A2 for each animal, or a pass/fail for a milk sample.
Our Murrah buffalo milk was confirmed A2A2 by TaqMan PCR — see the A2 Farmer lab report.
Can you test ghee itself for A2?
Not reliably. Ghee is ~99.7% fat with almost no protein or DNA left. That is why A2 is verified upstream — on the animals or the milk — and why a brand should be able to tell you which herd was tested and when. Then the ghee’s purity is checked separately (milk fat, moisture, Baudouin test). More on spotting weak claims: fake A2 ghee.
Is buffalo milk A2A2?
Yes. Buffalo beta-casein is of the A2 type, so buffalo milk and buffalo ghee are naturally A2. It is one reason we make A2 ghee from Murrah buffalo milk. For the full picture, read what is A2 ghee.
Frequently asked questions
What does A2A2 mean?
An A2A2 animal carries two copies of the A2 beta-casein gene, so its milk contains only A2 beta-casein.
How is A2 milk tested?
With a PCR DNA test, such as TaqMan real-time PCR, on hair, blood or milk samples, which identifies the animal as A1A1, A1A2 or A2A2.
Can ghee be tested for A2?
Not reliably, because ghee contains almost no protein or DNA. A2 status is verified on the animals or the milk before the ghee is made.
Are all desi cows A2A2?
Indigenous Indian breeds are generally A2A2, but crossbreeding means individual animals can differ, so herd testing is the reliable proof.
A2A2, confirmed by PCR
A2 Farmer Buffalo Bilona Ghee — A2A2 confirmed by PCR, 99.76% milk fat, hand-churned and glass-packed. From ₹799.
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