Genomic Heterozygosity
Genomically measured heterozygosity describes the percentage of an animal's gene loci at which two different alleles are present. The method of choice is determination using SNP arrays, which precisely analyse thousands of markers in the genome. The value thus shows the actual genetic diversity of the individual examined. High heterozygosity indicates a broad genetic base, which is often associated with good adaptability (genetic fitness) and robust health. Low heterozygosity, on the other hand, can indicate inbreeding or close kinship in the ancestral line and carries an increased risk of hereditary diseases.
Please note:
We are often asked whether the SNP marker profiles used to determine genetic identity can also be used to assess heterozygosity/genetic diversity. An example of such an ID marker set would be the ISAG2020 marker set for dogs.
The comparison shows that the values determined from the ID profiles differ significantly from the array-based values.
Our own investigations show that the ID-based values are almost exclusively far better than the real array-based values. This is not surprising, as the markers for the ID profile were selected under the specific requirements for identity and ancestry determination and in addition cover only a negligible proportion of the total genome.
There are no scientific publications that would prove that ID profile marker values are a reliable basis for determining individual inbreeding and heterozygosity/genetic diversity.
| Animal-ID | ISAG2020 | 170k-Array | Diff_abs. |
|---|---|---|---|
| 1_16_43 | 36,4 % | 24,1 % | 12,3% |
| 1_23_17 | 41,3 % | 28,7 % | 12,6 % |
| 1_24_190 | 29 % | 23 % | 6 % |
| 1_20_59 | 43,6% | 27,5 % | 16,1 % |
SNP-Markerwerte, die zur Bestimmung der genetischen Identität eines Tieres erhoben wurden, sind nicht geeignet für die Berechnung der korrekten individuellen genomischen Heterozygotie.