Observations Regarding Colour in Highland Blotched Blueys
Posted: 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).
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.
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.
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).
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.
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.