Observations Regarding Colour in Highland Blotched Blueys

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Scotts1au
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Observations Regarding Colour in Highland Blotched Blueys

Postby Scotts1au » Tue Dec 08, 2015 7:52 pm

Overview
I've been breeding Alpine Blotchies from the Blue Mountains area of Sydney Katoomba to Jenolen from animals that I'm reliably informed were directly descended from wild caught stock, prior to a licensing amnesty being implemented in New South Wales. Essentially my originating animals were quite diverse and close to wild type.

All of the animals have a degree of reddish tones through their blotches and undersides, although often only visible at in summer. Their "colouring up" is a function of the time of year, to some degree diet and their genetic makeup. To that end, some for much of the year have the appearance of yellow blotches, which turn pinkish in Summer. Others have strong orange tones which dominate their outward appearance for much of the year.

A process of colour change that occur across are likely an adaptation to their environment. For example, leaf fall in Eucalypt forests is strongly linked to the rate of growth and replacement of leaves, particularly in late Spring and early Summer. The dark background of Alpine Blotchies blends in perfectly with the shadowy undergrowth when blueys will be in this environment in this period.

Here is an example of how they look in their environment (actually this one in my enclosure - but you get the idea).
camoflague.jpg


Indeed pinkish blotches against dark background makes the very well camouflaged in Eucalyptus forest or woodland floor. Dead Eucalyptus leaves tend to take on a reddish tone prior to browning.

Underlying Genetics of Colour
I can’t profess to fully understand the genetic basis for colour variation – my contribution is observational, not scientific and limited to both my sample size and my exposure to these blueys in the wild (read Nil). Although I am familiar with their environment.

There is some indication that different genes governing colouration and pattern are located on different chromosome pairs and/or that some combinations of alleles (gene positions on chromosomes) may be repeated. On top of this, there is the spectre in attempting to understand what is going on that the same pairings may produce offspring differently to those which may be produced in a different environment (physical and/or developmental (read epigenetics)), so what I write here may not hold true in a different location or under all keeping regimes.

In general, it appears that individuals may exhibit stronger colours depending on how many times these combinations are repeated, the strength of the gene combinations at the allele and the absence, presence and/or expression of competing or additional genes controlling more dominant colours.

A factor leading to additional complexity is given that genes producing orange pigments may be located on a different chromosome, or position on a chromosome (Allele) to others, hence any individual may be heterozygous, or homozygous for one or more combinations that control the expression of colour. This may be the only explanation as to why colours tend to intensify with multi generational inbreeding. What is clear, is that expression of colour is also linked to a range of other factors, including the health or relative vigour of the individual.

In general, orange tones tend to be dominant to pinkish tones. Pinkish tones may also be absent in forms from other areas. I'm also contemplating the concept that yellow body markings may only occur where the individual is homozygous recessive for both orange and pink. Yellow features including faces have really only come to stand out in progeny resulting from back breeding to the parents where this has been done as an experiment.

Tones that create pink-reddishness tend to be dull early in development of a bluey and early in the season following brumation and may often be dominant later in a season if they occur in the individual. This means that a bluey that is orange in Spring may be quite strongly pink in Summer. There is some indication that the expression of genes controlling colour may be linked to seasonal reproductive cycling, i.e, orange when receptive to breeding fading to pink which I'll explain later.

There is some, but limited evidence to suggest that either absence of a functional gene or combination producing orange pigments, and/or failure of the reproductive cycle to initiate orange phenotypic expression may indicate an animal which may not be able to breed. It is likely that for both tones producing orange and pink that they have both generally recessive and dominant (weaker or stronger) genes located at their respective alleles, or in combination with other genes which control reproductive hormones for example.

Animals that are strongly orange, assuming that they have the pink gene will often produce babies that are strongly pink, although babies which are born strongly orange will likely remain strongly orange with only a hint of pink at certain times of the year. With Orange dominating the general appearance of the animal, it could still be homozygous dominant for pink but not visible due to the orange tones dominating.

A bluey which may be pinkish as an adult may be dull or even have the appearance of lacking colour completely as young animal. On the flip side, newborn babies can often have strong pink to red tones, such as on the head and the presence of genes which may strongly influence colour when the animal is mature may be indicated by a baby that has strong tones at birth. My guess is that It is likely that the expression of these red tones at birth results from exposure to hormones from the mother in utero. My reason for this is that these red tones tend to disappear within a few weeks of birth – only to re-emerge when the animal is mature.

The obvious temptation in these circumstances where colour intensity appears to be so strongly linked to the degree of inbreeding is to create strongly inbred lines. Care should be taken if purchasing an animal that is marketed as “high red” or other feature that might indicate significant line inbreeding. I fell for this one myself by buying animals marketed in this way from a seller, both of which failed to thrive. A strong physical indicator of animals likely to have this issue is a "spindly appearance".

My interest in attempting to understand the genetic basis is to be able to create blueys within desired colour ranges by matching parents rather than inbreeding.

Other Factors Influencing Colour

In general it appears that colour may be variable for a number of reasons including, in no particular order:

• Vigour/health of the individual
• Gender
• Time of year/Sexual cycling
• Temperatures experienced in any season
• Stage of life
• Genetics and other factors influencing expression
• Nutritional status
• Diet
• Environmental stress – eg. heat
• Stage of shedding cycle.

I’ve conducted some experiments on babies that seem to indicate that colour can vary – mainly the brightness of orange tones, as a result of feeding, temperature and other environmental influences. I observed that a day after eating a large amount of mushrooms, the colour seemed to intensify. However repeating the experiment with other foodstuffs that were nutritionally dense (eg. chunks of raw beef) seemed to produce a similar response.

It is likely that young rapidly growing babies are actually sub clinically deficient in nutrients that would otherwise be used to produce colours. This is simply because they are using them to grow and that they are likely to produce colours resembling an older individual if they are not deficient – although I don’t suggest forcing growth to approximate their genetic potential.

Males tend to develop reddish tones on scar tissue resulting tussles over girls, often giving older males a gnarly red appearance around the head.
Young sub-adult to young adult blueys often experience mottling around the mouth (stippling of small black dots giving the appearance of a bad teenage beard). Many also get darkening within the blotches as lines and the perimeter of the scales) giving a dirty appearance to the blotches which often fades when mature.

Colour intensity, particularly orange is often greatest the day after shedding has occurred. Shedding can be induced by wetting down the inside of the enclosure.

Case Study
This beautiful girl is the progeny of a Norman and Liz, both have strong pink tones and a degree of relationship between them.

She was born as a “runt” from the litter, near death at approximately 15 grams although she did eat moderately after birth, but as with many runty babies the egg sac was eaten by another baby. The other babies from the litter averaged around 30grams. Her markings were striking in that there was a complete lack of orange or other tones giving the baby a white and black appearance.

She has grown steadily and is now three years old, however disposition is generally lethargic and seemed to have a degree of paralysis coming out of brumation this year. She still has no orange tones visible however has been placed with males for the last 2 years – although they have shown no interest (note no mating scars).

From experience I could tell that she would come out with pink tones at a later stage, given the absence of orange tones at birth that would otherwise dominate. I had assumed that both parents were homozygous for weak orange genes (both move from orange to pink) but can generally be described as pink, meaning that all progeny would be homozygous for it.

For some reason there is weak expression of pink genes and none for orange.

My guess is that she has a endocrine problem which is limiting her vigour and sexual cycling. Despite having genes that would otherwise result in some orange colouring, expression is absent, probably linked to a hormonal problem which also limits vigour. The problem may have come out of utero as very hot temperatures were experienced during the pregnancy that produced this baby resulting in at least two stillborn babies. My guess is that, if she was to reproduce here progeny would still be the same as any other of the babies with the weak version of the orange gene.
Lizard2.jpg

lizard4.jpg

lizard3.jpg


Here are some examples of normal colour variation in related animals, note the bluey on the far right (downing a chicken bone) is the mother of bluey pictured above.
Lizards.jpg
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Re: Observations Regarding Colour in Highland Blotched Bluey

Postby Richard.C » Wed Dec 09, 2015 1:29 am

This is a great topic scott and something that really intrigues me,seems to me from observation to be a common thing though all forms of highlands

Its something ive watched with the vics for many years,and have noticed a few differences in babies and how they do it,suggesting that it is possably inheritable,last few seasons ive held some inddors for alot longer than i normally would and it seems to have also made differences in color,well lack there of with certain a imals losing yhe yellow and going an almost gold washed brown but being put back outdoors late last season the yellow is rapidly returning

At the same time ive had a couple indoors since birth that are as bright as any outdoors ones and that particular pr recently produced by far the brightest vic babies ive seen

I wouldnt mind trying to set some select nice animals up and seeing whats possable with them

Do u find that males are the ones that change color the most,i see that with mine but at same time some females do just as much


The first babies i produced from your line always kept a bright yellow and black coloration,i called the high yellows,they have been outddors for one summer a couple od seasons back but indoors the rest of the time,this season they have both turned ery orange,the female in particular which i believe is gravid

Will bave a look through so.e pics and see if i can find some examples of the color changes
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Re: Observations Regarding Colour in Highland Blotched Bluey

Postby kl » Wed Dec 09, 2015 9:09 am

This has been an interest of mine ever since I started working with Blotchies back in 2007. Here are a few of my observations based on a strictly indoor breeder.

I have noticed on some of my adults, after they get to be 5 to 6 yrs of age, the orange blotches seem to have faded a little. I've also observed that when babies are born, most are born with very little to no orange pigmentation in the blotches and achieve the orange intensity they end up with by the time they have had 3 shedding cycles. If they don't develop that color intensity after that, they generally don't. Every now and then, a baby will be born that exibits extremely orange color right away such as the 2 animals pictured here. Both have the same parents and are from different litters. Interestingly, neither parent shows this strong orange color. The very orange babies tend to be born much smaller than litter mates and not all the litter mates will share this color. This pairing has a very high percentage of stillborns and very small litters despite the female being very big. As for yellow blotched animals, I've got no experience because my founding group all had orange and only once in 9 yrs have I seen a baby born with yellow blotches.

I have a few questions. First, would diet influence an animal to have that orange pimentation in the blotches fade over time and if so, what might be lacking in animals that fade a bit. Secondly, would lack of natural sunlight cause it. This is interesting because some of the animals here were being housed outdoors year round in Florida since birth and subjected to very high temps for several months a yr. Those animals seem to have taken on a less intense orange color in the blotches than when they were younger which makes me think temperatures are the factor rather than natural sunlight. Even indoors, when temps get very hot the animals seem to look more faded and often look the brightest when temps are cooler. One note though, this reduction in orange intensity does not seem to effect the orange pigmentation sometimes found in the background coloration of the animals, only in the blotches. I'm not sure if any of this may be my imagination when trying to think back how they use to look a few yrs earlier and often photos are deceiving due to poor lighting and tinting caused by unnatural light from lamps. I say this because often friends who have obtained babies from me from several yrs earlier will send me pics of the animals and they still seem just as colorful as before.

I've never paid attention to details of coloration prior to mating season as a way to maybe predict success or if an animal is capable of reproduction and I found those comments on that subject very interesting and I'll have to see how they may apply here.

KL
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Re: Observations Regarding Colour in Highland Blotched Bluey

Postby Scotts1au » Wed Dec 09, 2015 4:21 pm

Mmm not sure that I can provide an explanation to those observations other than:
My older blueys (both male and female) have lost some intensity of colour with age.
My colours seem a bit better in blueys outdoors (however I haven't done A/B comparison with siblings) - observations may be simply different rates of maturation.
Richard I have some holdbacks that we can discuss ;-)
Both males and females seem to change colour about the same amount during the year (however all of mine have underlying pink tones).
Kim - I've had it reported to me that recessive high red adults that are related to mine produce smaller and fewer babies - possibly due to selection of this genetic combination being less viable (recessive genes on same chromosomes or expression linked to a "lack of" something controlled by a linked gene. A similar thing may be going on to your animals?
I've only had a couple of babies that I would describe as having the potential to be yellow, however I haven't kept them to see how they turn out.
Kim your blueys - I've only ever seen Alpines advertised as originating from the Oberon area that look in any way similar to the blotches on yours. Interestingly the person who I originally got my blueys from pointed out that the strong orange tended to come from that area - eg. West of Jenolan, which would make sense. Others have pointed out that this is outside of the Blue Mountains area, so there may be fundamental differences - eg. no genes for pink or red tones.
Generally my original stock blueys had very little yellow on their faces and feet etc, but backcrossing as F2 generation has yielded fairly high yellow faced babies. So I figure this is a recessive trait. From observation these babies with yellow faces are smaller than other related animals - so there may be other linkages there.

I may be able to post some more photos today to illustrate some differences.
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Re: Observations Regarding Colour in Highland Blotched Bluey

Postby Richard.C » Thu Dec 10, 2015 7:52 am

Scott that light one u posted above,is that related to stumpy,she looks alot like that at the moment with the light pink hue through her

Interesting those 4 have lightened right up since i got them,but still see pink and orange through them,the two i bred from one of your girls a few seasons back have gone the oppasite way,they went so bright yellow i was calling them yellows but now they have become very orange on me,lol,especially the female

I havnt had this form nearly long enough to tell what happens long term with them color wise,but the vic alpines hold there color well right through to old age

The biggest weird thing ive seen with them is some actually lose color early,buf as they get to sexual maturity,mine on average take a few years to get there the color returns and even intensifies and a few seem to just improve with age

Ive not noticed any thing like this in lowlands ,they seem to stay pretty much the same through out life
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Re: Observations Regarding Colour in Highland Blotched Bluey

Postby Scotts1au » Thu Dec 10, 2015 12:36 pm

Ther are several I've sold that I've kicked myself whe. I've seen them s year or two on, due them changing and colouring up. I expect that all of yours will show at least some pink, even if very subtle - late in the season. However the bright orange ones it will be hard to tell.

I think that stumpy was a baby from "flicker" who is on the left in the group photo above. She is about 60cm and 1.1 kg.
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