Sunday, 22 January 2012

A horse of a different colour part 6 - odds and sods

So, it looks like there will be a part seven of this series, and possibly even a part eight. However, first, here's part six, which is largely catching up on a couple of loose ends that I missed out on in earlier parts, and not the article I promised last time out.

First up, dappled greys.

I mentioned this very briefly in part two, but it merits a slightly longer note, since greys are pretty common (let's face it, if you have a British 1815 army, you need to paint some greys!).

Classic dappled grey
Wikipedia: Fabio Vidigal
CC BY-SA 2.5
Dapple grey is an intermediate stage, not seen on all horses, in the greying process, where the animal has a dark coat but with 'dapples', or dark rings with lighter centres, all over. It's an intermediate stage because, since grey is very analogous to the greying process in human hair (something I know about all too well), it won't last, and as the horse gets older it will tend towards overall grey or even white.

Much as it's tempting, and fun to paint, the odds are that even in a unit of grey horses, not all the horses will dappled.

Next up, the truth about the A gene, and seal brown horses.

Since I first started coding equine genetics online in the mid/late '90s, there's been some further research and discovery of aspects of the 'Agouti' gene, the A gene that determines the pattern of black pigment on horses. And just when you thought part one all made sense...

Seal brown horse
Wikipedia: public domain
There are, it transpires, multiple possible options for the A gene, as follows:
  • A+ - the original 'wildtype' A gene, dominant over everything, produces very restricted black pigmenting on mane, tail - seen in Przewalski's horse
  • A - the 'classic' bay as discussed in part one of this series, dominant over everything below it
  • At - less restricted black points, produces a 'seal brown' horse, dominant over...
  • a - no black points
So, our classic bay could be AA E, AAt  E or Aa E. The seal brown (i.e. AtAt E or Ata E), is visually and markedly different from either a bay or a black - it commonly has a dark brown coat, dark-to-black mane and tail, but touches of red around the eyes and muzzle, as well as parts of the underneath. In some parts of the world, this is called a 'black and tan'.

2 comments:

  1. Nice work, a very interesting subject!!

    ReplyDelete
  2. Thanks. It's good to know folks out there are enjoying it.

    ReplyDelete

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