fleabites changing colour - normal?

[Mehitabel]

as i was pulling out patches of hair from petal yesterday, i noticed that her fleabites seem to be changing colour. they've been a virulent ginger since they started appearing, but some of them now seem to be going black.

the ones round her eyes are still orange, but she has a very heavy streak of them down her shoulders - she is more ginger and black than white down them - and also a streak upwards from her stifles up to her hips, where the whorls are. i was pulling out ginger hair from the stifle area and seeing black hair underneath, so it is a very new thing. it definitely looks black rather than brown to the naked eye as well.

is she a freak, or is this normal? her mum is 19 now, and was still ginger-freckled last summer - i haven't seen her lately to see what she is doing.
other good news is that with the summer coat she still has a few dapples on her bum - her winter coat had been completely dapple-free, and all the fleabites were ginger, but summer coat looks like it is going to look very interesting this year.

no pics i'm afraid, but i will take some next weekend as she does look quite strikingly odd.

[chev]

That's interesting! Fleabites are a bit of an unknown quantity anyway to be honest; I've not seen any explanation for apparently producing pigment again after grey has basically prevented pigmentation. Nor has anyone found any correlation between the colour of teh fleabites and the original base colour, except to say that a chestnut gone grey will never have black fleabites because they can't produce black pigment.

So... Petal was sort of dark brown as a foal? So really it's probably more odd that she's had ginger ones all this time than to say she has very dark ones now, I suppose. Are they actually black? Or could it be that she was originally sort of seal brown and they are actually now more like the colour she is genetically?

I think if the mechanism that caused the pigment to be restricted in the first place was explained, that might give you your answer. Whatever it is in teh grey gene that casues that, grey also allows fleabites to develop; whether that is part and parcel of the grey gene or whether it's actually a related or linked gene is unclear. Certainly not all horses go fleabitten, regardless of whether or not they grey out very early on. So perhaps if Petal has Ee genes, that mechanism has allowed the red pigment to develop until now; and now (for whatever reason) the black is allowed too, you get your dark freckles.

I have seen fleabites darken like that before; but other than liver chestnuts (and only a certain proportion of them) that darkening is not really seen in the base colours. Apart from the liver chestnut variant (if Petal was liver chestnut originally I'd be thinking that explained it - but they wouldn't be black, and she didn't start off liver did she?), dark shades don't usually get darker; dark bay stays dark bay throughout life, as do seal bays and blacks. Even sooty buckskins like Copper and Kanuma's Stan don't darken over the years particularly.

I think it's more than likely a greater degree of pigment being 'allowed' in the hair shaft. There is a school of thought that says melanoma in greys develops because the pigment produced has to go somewhere - if not the hair shaft, then in the form of tumours. I'm not sure about that! - but it would make sense that whatever mechanism it is that first of all restricts pigment in the hair shaft in greys and then allows it in the form of flebites has allowed more of that to happen this season.

I have seen a few horses that started off with pale fleabites gradually get darker and darker ones; never seen one change as drmatically as this, but my guess is that that's what it is.

Piccies are a must... :D

[Mehitabel]

well, the attached pic is 2003 - definite ginger freckles there, and you saw the pic you used on your genetics talk, still pretty ginger then. this link is late last summer, they're browner but still brown.
http://historicalfact.com/~es/pony%20pictures/freckles.jpg

then i was plucking her yesterday, and you can see on the link that there were those slightly more concentrated parts on her shoulder - now her whole shoulder is much more concentrated, more like it is round her eyes, and some are ginger and some are black - and they look properly black. her sides are still woolly, so not sure how concentrated they'll be over the rest of her.

the streaky bit up from her stifle to her hip was very ginger in her winter coat - the only not white bits in the whole winter coat, actually - http://historicalfact.com/~es/pony%20pictures/barebackcanterheadless.jpg
the shadowy bit just in front of her hind leg isn't shadow, it's a ginger stripe going up there. i was pulling out the ginger hairs and seeing black ones underneath.

i asked on SU too, and it was suggested she may have been either sooty buckskin or sooty bay as a baby, and the sootiness is causing her to get darker with age?

her mum is ginger freckled too, her maternal grandsire was bay, so i presume the grey came from her granddam. anything could be lurking under it.
dad and both paternal grandparents are orange. mum and dad had 10 foals together, 5 bay (proper normal bright bay, nothing sooty visible) and 5 bay-gone-grey. she'd have had to be very very dark liver to be mistaken, i haven't any baby pics but here is her sister and they are more or less identical colour except petal was dingier and darker.

will definitely take pics on saturday, she went out naked last night and it is pouring with rain today, so i expect a fair bit more will have come out as she iwll be wallowing.

[chev]

Hmm.... there's definitely sooty there on her sister (and there will have been on Petal too, if she was dark brown). I'm not sure about buckskin. Yes, there's a vaguely yellow tinge to the sister's coat there - but foal coats are notorious for fading and even foals that definitely don't carry cream will usually go a yellowy shade as the foal fluff fades. This is Blod (http://img.photobucket.com/albums/v231/bronyfelin-ponies/bigbaby.jpg), showing the same kind of shading; and she's definitely not carrying the cream dilute.

It could be sooty; but I've never seen a bay get darker because of sooty. Then again, with grey complicating things, it could be sooty... although I still think it's more likely to be a progressive allowing of more pigment through teh grey, rather than an actual darkening based on the fact she's never been ginger!

[Mehitabel]

i will defintiely take pics on saturday. got a new arrival last night to take pics of too!

[chev]

Congrats on new arrival - definitely need pics now then! :D

[Mehitabel]

more pics from this weekend:

head, with very ginger freckles - http://historicalfact.com/~es/pony%20pictures/fleabitesface.jpg
flank - also very ginger, these are the ones i can just see black in the summer coat - http://historicalfact.com/~es/pony%20pictures/fleabitesflank.jpg
shoulder - much darker and more concentrated - http://historicalfact.com/~es/pony%20pictures/fleabitesshoulder.jpg

backside- also darker than they have been, and with fetching splodge - http://historicalfact.com/~es/pony%20pictures/fleabitesbackside.jpg

[chev]

They're quite amazing. The head ones are really ginger; if she was that colour, she'd be orange. And yet she's not chestnut based at all. They really do look like the black pigment is being 'blocked' from the hair shaft.

The ones on her body are obviously red and black pigmented - the same kind of colour you'd see on a sooty bay horse, which fits in with the colour she started off (I know fleabites don't reflect the base colour of the horse, but they do reflect what pigment can be produced in the hair shaft to an extent - you would never see black pigment in the fleabites on a chestnut based horse, for example).

I think there must be some kind of mechanism that means more black pigment is being 'allowed' through the action of the grey gene, which effectively prevents pigmentation in the hair shaft over the horse's lifetime. So the red pigment has been allowed for a while, and now you're seeing more black in places. I'll let you know if I find anything!

Love the splodge!

[chev]

Meant to add the shoulder is interesting; there's a marking known as 'bloody shoulder' that crops up mainly in Arabs, and it's like a rusty streak of pigmented hair on a grey horse. The streak is usually made up of closely-placed fleabites. I wonder if there's any relationship here?

[Mehitabel]

interesting - i wonder if that might be behind the arse-splodge too? it is much much more concentrated than it has been before, although i'll be able to see better when she is in proper coat.

her line is certainly quite araby-throwbacky, as you can see from her sisters - http://groups.msn.com/NRphotos/esspictures.msnw?action=ShowPhoto&PhotoID=195

http://keithcurtis.co.uk/onlinesales/equestrian/nfshow/Wednesday/Showing/Show%20Ring/NF%20Ridden%2011.20am%20-%202pm/805-3878.htm

[chev]

Could well be. A quick look through my genetics stuff has shed practically no light on fleabites at all :rolleyes: except for one theory put forward by a few people that fleabites are the result of a gene that acts on the grey gene; or a variant of the grey gene.

Showkayce (http://www.daydreamarabians.com/showkayce+_main.htm) is a great example of an Arab with a bloody shoulder; his is extreme, I've seen several who have teh same type of marking but not quite as loud! Although they're known as bloody shoulders they can occur elsewhere on teh body and will gradually become more and more solid as the horse ages. Some are only a couple of inches in diameter; others run teh length of the shoulder and down the leg.

As for genetics of fleabites... all in the realm of theory, it seems. There are still plenty of people saying the fleabites will be the same colour as the horse's base colour; obviously not the case with Petal (or several other greys I've known well). There's also a theory that fleabitten greys are the result of two grey genes (also not the case - I've known greys with one solid parent who developed them - and isn't Petal's dad orange?) and another theory that says fleabites are freckles of colour that never go grey. Which they're not - as has been seen in the way Petal's freckles have got more prolific over time.

So I still think the most likely explanation for Petal's getting darker is that whatever variant of grey or related gene causes freckles of pigment to be allowed back into the hair shaft again does so in stages; so red is seen, in increasing concentration, and then black, if black exists in the horse's genotype.

[Mehitabel]

thanks, this is very interesting. her dad is indeed orange.