About Polled Genetics
What do Homozygous, Heterozygous and Scurred Mean?
The polled/horned gene is viewed as a simple dominant, recessive inheritance. Each parent contributes one copy (allelle) of the gene to the calf.
The two alleles are : P = Poll and H= Horn
Every Animal carries 2 copies of the gene, The 3 possibilities are PP, PH, and HH.
Polled is dominant to horned. This means that whenever a polled gene is present, the animal does not have horns.
- PP-Polled – this is called Homozygous Polled
- PH – Polled – this is called Heterozygous Polled. Scurs are possible*
- HH – Horned
Scurs are small, loose horns or flat bone growth, which are only expressed in heterozygous polled animals.
*expect a higher incidence in males than females.
Homozygous polled animals will always give you polled, or scurred progeny, even when crossed over horned animals
When crossed over fullblood Wagyu, which are 100% horned (HH), every calf will be polled, or scurred.
When Crossed over Heterozygous polls, 50% of the progeny are homozygous polled, and 50% are Heterozygous.
When crossed over homozygous polls, 100% of the progeny are homozygous polled.
Heterozygous polled animals will give you a combination of polled, scurred and horned progeny depending o what they are crossed with.
When crossed over fullblood Wagyu, which are 100% horned (HH), 50% of the progeny will be polled, or scurred.
When crossed over heterozygous polls, 25% of the progeny are homozygous polled, 50% heterozygous, and 25% horned
When crossed over homozygous polls, 50% of the progeny are homozygous polled and 50% heterozygous polled