A Colour Genetics Guide

[Marigold4]

Here she is. The stripe along her back is quite visible. Are these faint primitive markings/bars on her legs??

 

[Jeef Perky]

According to https://www.equinetapestry.blog/roaning-and-white-ticking/ there are several genetic things that cause white ticking and/or roaning. I'm in the USA so my terminology and frame of reference reflects that.

I associate "true roan" with foundation quarter horses with Hancock breeding -- dark head and legs, white hairs mixed with base color on body. They look markedly different in their winter vs summer coats. Foals may take some time to develop the roaning. It's definitely not the same as grey.

"Skunk tail" / rabicano puts the white hairs around the tail head. Some thoroughbreds have this.

Sabino roan causes white ticking on the body of horses with extreme sabino markings. Think Clydesdales. Some can be neatly all-white. There are several variants of sabino gene -- some may do this more than others.

Dominant white at varying degrees of expression can resilt in roaning.

Varnish roan is one variation of leopard complex (appaloosa) and is distinctly different from quarter hoarse roaning. Appaloosas in general can have some pretty extensive (or minimal) roaning, even on the same horse as time goes by.

Tobiano pintos can have roaning at the borders of the pigmented spots, or larger roan spots. Other white spotting genes may influence this, but the Tobiano pattern csn make those invisible without genetic testing.

UC Davis is constantly adding more color genes to their testing. Maybe it's because horses in the Americas are unusually rich in peculiar patterns and colors, whereas Europeans lean more conservative in what colors they breed for.

Sorry 'bout the duplicate posts above -- the 'add link' button sneakily overlays the 'post reply' button.

 

[Jeef Perky]

Here she is. The stripe along her back is quite visible. Are these faint primitive markings/bars on her legs??

Yeah, that's a very obvious dun dorsal stripe.

 

[Cloball]

@Marigold4 they do look like leg stripes but I agree her coat doesn't have the right dilution I wonder if she is Nd1 instead. I think @Caol Ila ha a mare with Nd1 that is similar.

 

[Marigold4]

@Marigold4 they do look like leg stripes but I agree her coat doesn't have the right dilution I wonder if she is Nd1 instead. I think @Caol Ila ha a mare with Nd1 that is similar.

I think that must be right - that she is Nd1. Main thing is that we got her colour right on her passport. She IS a bay dun!

 

[ester]

Nd1 to me too - generates primitive markings but no dilution. She’s def bay

 

[FieldOrnaments]

My little one is homozygous nd1 and is really pale. It causes the pigment to be distributed asymmetrically in the hair shaft the same way dundoes but to a lesser degree, so does cause slight dilution in some individuals


this is an old pic, she's nowhere near as fat now, but unfortunately she has cushings and her coat quality has gone downhill as a result

 

[Marigold4]

My little one is homozygous nd1 and is really pale. It causes the pigment to be distributed asymmetrically in the hair shaft the same way dundoes but to a lesser degree, so does cause slight dilution in some individuals
View attachment 143295

this is an old pic, she's nowhere near as fat now, but unfortunately she has cushings and her coat quality has gone downhill as a result

Sorry to hear she has cushings. She looks very much the same colour as mine, doesn't she?

 

[rhino]

I think that must be right - that she is Nd1. Main thing is that we got her colour right on her passport. She IS a bay dun!

Dun is first and foremost a dilution gene. Your horse has no coat dilution, I’d agree with bay nd1 (which is not dun 1 gene). She’s not bay dun IMO.

 

[Marigold4]

Dun is first and foremost a dilution gene. Your horse has no coat dilution, I’d agree with bay nd1 (which is not dun 1 gene). She’s not bay dun IMO.

That's interesting. So she is a bay then and the stripe along her back and into her tail, and primitive markings on her legs are irrelevant? And any horse with a bay colour cannot be a dun?

 

[rhino]

The primitive markings are not irrelevant but are down to the nd1 gene, not the dun gene. There are lots of different shades of bay dun - mine is very ‘yellow’ but they do look diluted in comparison with a bay.

How is your girl bred? There’s not that much dun in uk breeds, relatively speaking.

 

[Marigold4]

The primitive markings are not irrelevant but are down to the nd1 gene, not the dun gene. There are lots of different shades of bay dun - mine is very ‘yellow’ but they do look diluted in comparison with a bay.

How is your girl bred? There’s not that much dun in uk breeds, relatively speaking.View attachment 143901

Her sire is Killour Star, a buckskin connemara. Mum is a British warmblood by Royaldik, an Oldenburg. She is a very dark bay, almost black in the winter. Here's a link to Killour Star. https://www.barrowbyconnemaras.co.uk/killour-star

 

[Gloi]

Yeah, that's a very obvious dun dorsal stripe.

A dorsal stripe but the head isn't darker, coat faded, like a dun so I'd suspect ND1 rather than dun.

Sorry , hadn't read all thread.

 

[rhino]

Her sire is Killour Star, a buckskin connemara. Mum is a British warmblood by Royaldik, an Oldenburg. She is a very dark bay, almost black in the winter. Here's a link to Killour Star. https://www.barrowbyconnemaras.co.uk/killour-star

Connemaras have cream, not dun. They’re different genes and coat colours, although some still insist on using them interchangeably.

Buckskin x Bay can NOT produce dun offspring. Yours is definitely a beautiful bay.