7 new mutations in KIT found, including two more TB DW!!

[summerhorse]

I don't know, I still take the Bowling study with a grain of salt as from what I remember she did not have photographic evidence of all the "roans".

the Hancock horses are also questionable as they have a mixture of frosty roans (not lethal) and regular roans and probably combinations of both on that page. And that is still a very small number of "homozygous" stallions. I'd lend more credence to the breeders with experience of breeding roan to roan and ending up with 1/3 to 2/3 ratios.

I am glad there seems to be research in this area but until it is published it can't really be considered a scientific source. After publication of course it is different.

[Linda_d]

I would think that the existence of "regular" true roans and "frosty" true roans may very well indicate the existence of 2 different genes or mutations that behave just differently enough that they are not lethal.

Moreover, as I understand the UC Davis testing, they don't actually test for the roan gene but markers for it. Could the same markers be pointing to two different versions of the roan gene?

[Pan Zareta]

Moreover, as I understand the UC Davis testing, they don't actually test for the roan gene but markers for it.

Correct.

The markers are accurately predictive of roan, but the roan mutation itself has not been identified.

Could the same markers be pointing to two different versions of the roan gene?

They *could* be, yes.

Have any frosty roans been tested and proven to exhibit the same markers used to identify true roan?

Last I heard, the idea that true roan and frosty were controlled by the same gene was unproven but reasonable since frosty is observed only in the same breeds in which true roan occurs.

[summerhorse]

Don't know about what controls frosty roan and true roan or how they are related. I think they probably are different genes because of the lethal thing and the distribution pattern.

[accphotography]

Frosty roan and true roan are one and the same. Breeding has proven this time and time again.