Post by dexteraddict on Oct 18, 2014 7:14:58 GMT 10
The Dexter Genetic Colours
Black and red colour share the same gene. So this gene will only ever be red or it is black.
There are always TWO copies of this gene, one from each parent.
TYPR1/b (dun) gene can attach itself to this gene whether it is a red or a black.
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The below explains different scenarios
ED = Black
b = Dun
E+ = Wild red
e = True red
The Black Dexter
The black gene ED is dominant. If a Dexter has only one copy of ED, then it will appear black irrespective of what colour the other gene is.
If the Dexter has two copies of ED (one from each parent) then it will appear black.
| ED/ED | black coloured only |
| ED/EDb | black coloured but dun carrier |
| ED/E+b | Black coloured but dun AND red carrier |
| ED/eb | black coloured but dun AND red carrier |
The Dun Dexter
If the Dexter has only one copy of TYPR1/b (dun) attached to one copy of black and the other black gene does not have TYPR1/b (dun) attached, then the Dexter will appear black, but will be a carrier of dun.
ALL dun-coloured Dexters are carriers of black.
| EDb/EDb | dun coloured – but because there is also at least one copy of the black, duns are always black carriers |
| EDb/E+b | dun coloured but red AND black carrier |
| EDb/eb | dun coloured but red AND black carrier |
The Red Dexter
Reds can be either Wild red or True red, and then they could also be capable of producing dun depending on their mate’s genetic colour makeup
Red Dexters can carry the TYPR1/b (dun) gene or even two copies of the TYPR1/b (dun) attached to each red gene, but because the protein will only dilute black, the Dexter will always appear red.
This is why the saying only two red Dexters will breed true.
| E+/E+ | red coloured |
| E+/e | red coloured |
| e/e | red coloured |
| E+b/E+ | red coloured but capable of producing dun if mate has black gene + b given to progeny |
| E+b/E+b | red coloured but capable of producing dun if mate has black gene + b given to progeny |
| E+b/e | red coloured but capable of producing dun if mate has black gene + b given to progeny |
| eb/e | red coloured but capable of producing dun if mate has black gene + b given to progeny |
| eb/eb | red coloured but capable of producing dun if mate has black gene + b given to progeny |
Colour testing of parents is the only way to guarantee what colours are ‘possible’ in your calves. It’s a percentage game.
Hope this helps explain 
