Thursday, May 24, 2018

genetics_101

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Category: Schnauzer Facts

 * updated 8-15-2012, still working on all references .

First a look at the canine general population.

Note : since the field of genetics is rapidly changing and scientific research

is still isolating all the gene markers .

Many of these markers have been bred out of,

or never existed in schnauzers.

The following pictures are only to  illustrate the color. 

 

Canine Coat colors are made up of  chemicals that determine color, and the markers that effects these chemicals.. 

  1. Tyrosinase - allows the creation of melanin or what creates color (*C, *cd,  *c, *cb,)  although dogs do have Tyorsinase in there coats the C marker has not been proven in the canine species yet.
  2. Phaeomelanin - colors the coat yellow-red (I , i, ee , *C, *Cch)
  3. melanophilin -  this protein will dilute Eumelanin hair colors (d)
  4. Eumelanin
black eumelanin - grey, black, (B,E,Em,Kb,Cch,D,d)
brown eumelanin - yellow,  brown (b,Kb,E,Cch,D,d)

 

overview of the markers in dogs that make up coat color  :

Color markers: (markers with " * " are theoretical markers)

 

 crossed out text is older theory (2010) that has been but back under scrunteny , but I am waiting on a paper to link too before completly removing it . ..

marker code Type of effect Illustration description
Ay pattern

Ay red II red

agouti wild Ii med

Ay red ii light

Ay yellow

fawn cream to yellow to red with darker tips some solid (eumelanin) black hairs intermingled amongst reddish hairs dominantly phaeomelanin based coat

  • Ay II full intensity  red 
  • Ay Ii med intensity  red
  • Ay ii light intensity red
  • Ay cream
aw Pattern

 agouti wild red

agouti wild Ii med

agouti wild ii

wild color of sable black  (eumelanin) tips on (phaeomelanin) cream to red hairs

 

  • aw II full intensity  red banded sable
  • aw Ii med intensity red banded  sable
  • aw ii light intensity  red  banded sable

 

 It is possible that another marker my be  effecting the banding vs solid color coats , while  the "aw"  "agouti" protein controls the production of   eumelanin   switching to  phaeomelanin  in individual hairs , it also seems to creat a bi-colored coat pattern.  In miniature schnauzers all black and silvers appear to have tested homozygous awaw.

 

at pattern

brown tan IIblack tan II dark

brown Ii medblack tan Ii med

brown iiblack tan ii

Tan pointed. face eye brows, points, legs and belly are colored by phaeomelanin . 

  • at II brown & red /black & red
  • at Ii brown & tan / black & tan 
  • at ii brown & cream/ black & silver

 

"at" may possibly not exist in schnauzers , and the tan/white point could be caused by a yet undetermined gene, similar  Eg in Saluki's.

I do not have reference material for this new finding yet and will update as soon as I have it. 

As* pattern

saddle II dark bsaddle II dark B dark

saddle Ii med bsaddle Ii med Bl

saddle ii lightsaddle ii light B

new information from studies done in 2012 observe *Saddle * is actually  an extension of "at", tan point. 

  • saddle is assumed to exist in theory
  • as II brown & red/ black & red
  • as Ii brown & tan/ black & tan
  • as ii brown & cream / black & silver
a solid brownblack

Recessive solid eumelanin only, 

inhibitions production  of phaeomelanin

B solid black

black eumelanin dog will be base black ,The nose leather, pads, and eye rims are also affected by this gene and will be black

b solid brown

brown eumelanin dog will be base brown, The nose leather, pads, and eye rims are also affected by this gene.and will be brown

C* solid c albino

C is unknown in canines and is a theoretical marker. 

Tyrosinase ,Full color,animal genetic  sites have slightly varying definitions.

but according to The Genetics of the Dog, 

By Elaine A. Ostrander, Anatoly Ruvinsky.

"C" simply doesn't dilute phaeomeanin, and has no effect on Eumelanin. 

Cch* solid

Red chincilla Cch

Dilute black blue

Dilute brown fawn

Chinchilla partial inhibition of phaeomelanin resulting in decreased red pigment.

  • Some new research believes it will also dilute Eumelanin
cd* solid  cd white dark skin White:  leads to white coated dark eyed dogs with black noses and pads. Inhibits Tyrosinase production
cb* solid  cb white blue eyes Cornaz: leads to white coated blue eyed dogs. Inhibits Tyrosinase production
c* solid  c albino Albinism*: white coat pink nose and pads. Inhibits Tyrosinase production
D solid brownblack  No Dilution to Eumelanin
d solid
Dilute brown fawnDilute black blue

Dilutes Eumelanin

  • black "B" becomes blue
  • liver "b"  becomes fawn 
Em Pattern  Em mask  mask ii Mask animal expresses eumelanin Mask on face,  will be black or brown, body color not effected 
E solid brownblack No mask animal expresses eumelanin. coat can produce  eumelanin  and be  black or brown 
Eg Pattern  redbase Eg Ii grizzle

Grizzle/Domino dark overlay covering the top and sides of the body head(widow's peek) and tail and the outside of the limbs hairs are  eumelanin  banded, darker at tips.

example :a base colored Phaeomelanin(red),with an eumelanin overlay pattern

e solid  red No mask animal does not express eumelanin coat will be Phaeomelanin red or yellow
G* solid

black->Dilute black blue

brown->Dilute brown fawn

red->Red chincilla Cch

 “progressive greying”

eumelanin

born black turns blue,

born brown turns fawn,

 

Phaeomelanin - born red/yellow turns apricot/cream (less noticeable)

g* solid

blackbrownred

Graying born black stays black, born brown stays brown 

born red/yellow stays red/yellow

I solid black tan II darkblack tan II dark

Intensity – effects Phaeomelanin that  colors the coat yellow-red this  marker I produces the deepest red

(examples are tan pointed dogs exhibiting at)

Ii solid brown Ii medblack tan Ii med

Intensity – effects Phaeomelanin that colors the coat yellow-red  marker Ii produces a tan.

(examples are tan pointed dogs exhibiting at)

ii solid brown iiblack tan ii 

Intensity – effects Phaeomelanin that  colors the coat yellow-red  marker ii produces a cream-white

(examples are tan pointed dogs exhibiting at)

K or Kb solid

brownblackred

Will Mask the pattern at “A” and express the Color at ”B”&"e"
Kbr Pattern  brindle red tan blackoverlay

Brindle 

 

example: red/tan(Phaeomelanin) with black (eumelanin) stripping

k or ky solid  see "A" allows the full expression of the “A” Loci
M Pattern

 

black tan blue Merel

double merel leathel

Merle visible in dogs that are not e/e

  • black and tan single merle,
  • black and tan double merle (lethal white)

http://merleminiatureschnauzers.weebly.com/

m soild  not merel  Non-merle
S solid  any solid  Solid color small areas of white may appear on chest toes or tail tip
si Pattern

 irish spot eeirish spot b

irish spot Bl

 

Irish-spotting white on muzzle forehead feet legs chest and tail

  • si ee
  • si b 
  • si black

 

sp Pattern

 spotted ee

spotted b

spotted Bl

Pie-bald spotting large areas of white

  • sp ee yellow/red
  • sp b brown/liver
  • sp B black 

 

sw Pattern

 ex spotted ee

ex spotted bb

ex spotted b

Extreme pie-bald spotting Extremely large areas of white almost completely white.

  • sw ee yellow/red
  • sw b brown 
  • sw B  Black

 

T Pattern  black tan irish ticked

Ticked : ticking effects the white areas of a dog, it allows tiny spots of the dogs base color to show through.

  • example :a black and tan, Irish spotted  dog with ticking
  • at/II/si/T
t solid  black tan irish

Non-Ticked

  • black and tan / II /Irish spotted  with no ticking

 references:

 


Modern Purebred Schnauzers (USA) 

Colored based on Black eumelanin (B-,E-,K-), all schnauzers at "ii" intensity  where the red/yellow Phaeomelanin does not express , or as in "red pepper, expresses very slightly as banded  tan .

 


 

"A" notes for schnauzers:

  • Schnauzers do not seem to  carry the dominate "Ay" "red/yellow sable".
  • "aw" is the wild color, this created the banding in the salt and pepper coats, it is always doubled with the "ii"  light intensity marker,  marker "ii"  dilutes the intensity of Phaeomelanin the most and will create a very white or cream color instead of  deep reds and yellow/tans. Their are salt and pepper and red pepper schnauzers, red pepper is a "aw" coat with a little more Phaeomelanin in it. their isn't a lot of Phaeomelanin, but a few tan colors hairs and tan in the banding occasionally will show through.
  • If the "as*" saddle is present, this is still a theoretical marker, It rides very low on the schnauzers back extended to the legs. If "as" doesn't actually exist , it may actually be the Eg marker.
  • "at" the pointed marker, in Schnauzers is coupled with "ii"(dilutes the intensity of Phaeomelanin) and where the points would normally be tan or red, they area white "silver , or very pale cream.

    New studies seem to have disproved that "at" is present in schnauzers, although it seemed to be present  historically.

  • "a" is recessive black, it allows the full expression of the markers at "B" this gene only seems to exist in herding breeds and dosen't manifest in schnauzers.

 

 

agouti wild iiblackblack tan ii

aw ii (B)                               B,Kb,E                                EG*?, at?? ii  (B)

 


 

 

"B"  notes for schnauzers:
  • All pure bred schnauzers appear to be dominate "B" for black eumelanin.
  • Well bred schnauzers do not carry for (b) brown eumelanin. 
 

 
"C"*: Chinchilla locus  Schnauzers are believed to be dominate "C" solid 
  • C*- solid color 
    • More likely  "C" is simply an on switch for Tyrosinase and it allows full exhibition of both  Eumelanin and Phaeomelanin.
    • "C" simply doesn't dilute phaeomeanin, and has no effect on Eumelanin
    • If Phaeomelanin is stripped by the "ii" intensity marker an animal who is "C"  exhibiting "red" with "ii" would be light cream or white if they were also unable to produce or exhibit eumelanin

  • Cch* Chinchilla : dilutes the red Phaeomelanin pigment. it's passable that a Cch/ii dog could appear white or cream, if they were also unable to produce or exhibit eumelanin. Cch does not itself effect the production of eumelanin.
  • cd*   Inhibits Tyrosinase production in the coat , but allows eumelanin in the lips, eyes , nose and pads dog would have a white coat  ,This is the color type  of the german "white " schnauzer and could be a possible associated gene..
  • cb*   Inhibits Tyrosinase production in coat as well as nose and partially in the eyes , dog  would have a white coat, pink nose, and blue eyes. This is not exhibited in schnauzers even "white " ones
  • c*     Inhibits Tyrosinase" true albino ,no color is produced .
 

 
"D" and "G" - Dilution / Progressive Graying
Diluted animals would be a lighter color from birth, Progressive gray animals would fade over time. 
Most likely Schnauzers are  Dominate for "D" no dilution , and recessive "g" no progressive gray.
 D: no Dilution, animal will exhibit the color at "B"

 

  • d: Dilution of eumelanin, "d" only effects the black and brown eumelanin

 

  • G: progressive greying, this effects the canine coat color over time , a dog will be born , Black , Brown (eumelanin) and Red (Phaeomelanin), as the animal ages it's color fades .

  

  • g: no graying

 


 
"E" Extension  notes for schnauzers:
"Em" and "E" are confirmed for the US purebred miniature schnauzer , e/e may only exist in German Whites
 which is in Germany a separate breed .
  • "Em" dominate this expresses a mask on the face , colored with the animals black or brown eumelanin at "b".
  • "E" no mask but expresses the coat color at "A" "k" "B".
  • "Eg" Grizzling/Domino found in Saluki and Afghan Hound, not know in Schnauzers
  • "e/e" recessive this masks the black or brown eumelanin at "B", and creates a Phaeomelanin based uniform  yellow.
 

 
"I "intensity  Phaeomelanin Modifier 
All schnauzers seem to carry the most dilute modifier of this type . "ii" Strips most of the Phaeomelanin out of 
the coat and where Phaeomelanin would be a very light cream or white is in it's place because the Phaeomelanin pigment is not produced 
  • I - Red (bred out of schnauzers )
  • Ii- Tan (bred out of schnauzers )
  • ii- very light tan -> cream ->white 

 


K effects on schnauzer colors 

  • Kb/K: masks all color patterns  at "A"  will express what ever is at " B" or "e/e" 
  • Kbr : Brindle not a schnauzer color 
  • ky/k : allows full expression at the "A" locus.

 


Merle:  not historically  present in schnauzers 

Although you will see Merle schnauzers advertised online these are not purebred. there is more info on non-schnauzer colors here.

 


Roan:  not historically present in Schnauzers 

 


Spotting : Spotting occurred in the very begging of the breed , But ONLY white dogs with even black spots  were ever whelped.  more here

 


Combinations/mutations that could cause " white miniature schnauzers".

Stacked Dilutions not  in US schnauzers and not likely in German white  Schnauzers  

These types of dilutions would produce the "designer" 

"C" is still a theoretical marker ,It's passable that a Cch/ii/DD/ dog could appear white or cream, if they were also unable to produce or exhibit eumelanin.  Dilution is less likely because the "d" dilute marker also dilutes the eyes and nose , of the dog and the German white have black noses.

In theory "cd"  which strips all color from the coat but doesn't effect nose and eyes membrane color.

  Ay/ii/D could produce a dog stripped of most Phaeomelanin and eumelanin. It would appear very light BUT would probably  also have a diluted nose.

  e/e in a black dog, this marker would block the production the eumelanin , and the ii intensity marker would then strip any  Phaeomelanin out of the coat .

 

 Salt and Pepper

 

 

awawBBCCDDEEggiikyky salt and pepper salt pepper no mask awawE agouti- salt & pepper | B-Black|C-no dilute color | D-no-dilute | E-no black mask| no-graying| ii-all tan points diluted to silver | kyky- recessive "off switch ", allows full expression of color at A loci of color art A loci)
awawBBCCDDEmEmggiikyky salt and pepper salt pepper mask awawEm agouti- salt & pepper | B-Black|C-no dilute color | D-no-dilute | EmEm homozygous - black mask| no-graying| ii-all tan points diluted to silver | kyky- recessive "off switch ", allows full expression of color at A loci of color art A loci)
awawBBCCDDEmEggiikyky salt and pepper salt pepper mask awawEm agouti- salt & pepper | B-Black|C-no dilute color | D-no-dilute | EmE- black mask| no-graying| ii-all tan points diluted to silver | kyky- recessive "off switch ", allows full expression of color at A loci of color art A loci)

 

Black and Silver

       

atat?

BBCCDDEEggiikyky

black and silver  blackandsilver pointednsaddle no mask asatE agouti- black and silver " black and tan pattern" | B-Black|C-no dilute color | D-no-dilute | E-no black mask| no-graying| ii-all tan points diluted to silver | kyky- recessive "off switch ", allows full expression of color at at loci

atat?

BBCCDDEmEmggiikyky

black and silver  blackandsilver pointednsaddle mask asatEm agouti- black and silver " black and tan pattern" | B-Black|C-no dilute color | D-no-dilute | EmEm homozygous - black mask| no-graying| ii-all tan points diluted to silver | kyky- recessive "off switch ", allows full expression of color at at loci

 domino/grizzle in schnauzers???

 

awaw?

BB

EgEg?

ii

kyky ....................................

black and silver

..........

 blackandsilver mask asasEm agouti- black and silver " black and tan pattern" | B-Black|C-no dilute color | D-no-dilute | EgEg Grizzle/Domino pattern?| no-graying| ii-all tan points diluted to silver | kyky- recessive "off switch ", allows full expression of color at at loci

 

 Black dogs:

 

       
awawBBCCDDEEggiiKbKb black black soild agouti-salt & pepper | B-Black|C-no dilute color | D-no-dilute | E-no black mask| no-graying| ii-all tan points diluted to silver | Kb- Dominate Black Masks pattern gene at A loci
awawBBCCDDEEggiiKbky black black soild agouti- salt & pepper | B-Black|C-no dilute color | D-no-dilute | E-no black mask| no-graying| ii-all tan points diluted to silver | Kbky- Dominate Black Masks pattern gene at A loci(carries for "off", allows full expression of color art A loci)
awawBBCCDDEmEmggiiKbKb black black soild agouti- salt & pepper | B-Black|C-no dilute color | D-no-dilute | EmEm homozygous - black mask| no-graying| ii-all tan points diluted to silver | Kb- Dominate Black Masks pattern gene at A loci
awawBBCCDDEmEmggiiKbky black black soild agouti- salt & pepper | B-Black|C-no dilute color | D-no-dilute | EmEm homozygous - black mask| no-graying| ii-all tan points diluted to silver | Kbky- Dominate Black Masks pattern gene at A loci(carries for "off", allows full expression of color art A loci)