Umbrous

[Dood]

I learned something new today

"Umbrous" is the term used to describe the dark modifiers that make some torts almost black and others almost orange

It can do the same for all colours

- super dark Havana chocolates have a lot of umbrous modifiers while the redder chocolates like Amber rex lack umbrous and have a lot of Rufus factors

- sallanders that are washed out lack umbrous factors and the Skeltor-like black and white sallanders have them

Umbrous modifiers also explain why sable point littermates without the himi or REW gene to interfere, can be have a huge range of shades from very light to almost looking like siamese sable - see picture

 

[Susie570]

Nice... I'm never going to remember that, but good info!!

Actually, I might remember it because it sounds like 'umbra' which means 'shadow of' or something like that, so it makes sense.

Ah, here we go: http://en.wikipedia.org/wiki/Umbra,_penumbra_and_antumbra

 

[alforddm]

So then Rufus is the darkening of the Red coloration? <br /><br /> __________ Thu Apr 09, 2015 9:11 am __________ <br /><br /> I've also seen the darkening call "melanistic" specifically in regards to black wolves, deer, and squirrel.

 

[katiebear]

So then Rufus is the darkening of the Red coloration?

__________ Thu Apr 09, 2015 9:11 am __________

I've also seen the darkening call "melanistic" specifically in regards to black wolves, deer, and squirrel.

The pigment in the skin is melanin so that makes sense....
Umbra sounds like amber which is a golden or reddish color..right?

 

[Dood]

I wouldn't say darkening of red but definitely intensifying it

A self black is a melanistic rabbit but due to domestication we've got wayyyy past one colour mutation and need to be more specific

umbrous - Latin, from umbra shade, shadow

 

[Miss M]

Neato!

 

[Zass]

Interesting. Do you suppose it has any affect on steels?

 

[Dood]

I don't see why not

 

[twr]

Robinson defines umbrous as darkening modifiers that affect the agouti pattern (where black is already intense), by modifying the extent of black (i.e. similar to steel but with a white belly). That book specifically cautions against assuming that the modifiers that affect the intensity of black in shaded colours are the same as those that affect the extent of black in agouti.

Personally I'm not convinced that the current state of knowledge is better than "there are some poorly understood darkness modifiers", in which case assigning names seems premature.

 

[Dood]

I agree it's ambiguous but it sounds so much cooler :mrgreen:

I've got two homozygous sable does and the one regularly has torts that are so light they look like low Rufus reds with just a smudge of tort shading on the nose while the other doe has tort kits that come out black and their markings start to come in later and it always drove me nuts that they should be so different - now I can say it's "umbrous modifiers"

They use the term a lot in decribing mouse colours so I assume it is better understood I that species