HGG Community Forums

Yes, Ee Aa would be the minimum change required to make it bay.

Yes, the Agouti gene can only be activated or 'switched on' if the horse has at least one of the dominant alleles of the extension gene, either EE or Ee.

And can be either homozygous dominant or Heterozygous for the dominant Agouti allele - AA or Aa. However if your horse is heterozygous for the Agouti gene, then the alleles for wild bay (A+) and brown (At) would mask the black allele (a) and turn your horse its respective colour. However the dominant classic bay allele (A) masks them all, except wild bay

EE/Ee AtA = Classic Bay
EE/Ee Ata = Brown
EE/Ee A+A = Wild Bay
EE/Ee A+a = Wild Bay
EE/Ee AA = Classic Bay
EE/Ee Aa = Classic Bay
EE/Ee aa = Black