Analysis of feather colours of varieties
Yellow and red feathers
Lutino and Rubino varieties
Two different approaches to analyse a variety
There are two different approaches to analyse a variety: Analysis of the mutated gene (1) Analysis of the changed colours of a variety (2) .Both approaches are used in practice and research. The results of this two approaches are used to namegiving (3).
1. The first approach is aiming at the knowledge of the mutation factor of a variety. The scientific background is formed by genetical research.
2. The second approach is aiming at the description of the new appearance of the variety, comparing the new variety with other varieties and the original wild-form. The scientific background is formed by tissue studies, histological research..
Genetics and histology are both succesful sections of biology. Genetic research is used to find out the explanation of the causes of new varieties. Histology is the science of tissue studies. This kind of research is used to describe and explain colour deviations of the plumage. The two approaches complete each other.The mutation breeder has to know the colour characteristics and the inheritance of the new variety. The breeder of varieties of a bird species can take advantage by the results of research in this aereas.
3. Namegiving is using both approaches Every bird species has two names::a common name and a scientific name Every variety of a bird species has two names also. The scientific name of the Bourke's parrot is Neopsephotus bourkii. We get the scientific name of a variety of this bird species when we add the name of the mutation factor to the scientific name of the species. Example: Neopsephotus bourkii (M-t+) M means melanin, t&Mac173; means tyrosine. We get the common name of the variety when we add the name of the characteristic colour to the common name of the species. Example: Lutino Bourke's parrot.
Example of both approaches, lutino variety
Every variety of a bird species has a changed appearance (phenotype) and a changed genetical make-up (genotype)
ad 1.The first approach means: genetic research
This approach starts with the genotype. Every bird species have his own specific genetical make-up. Study of varieties starts with the analysis of the altered genetical make-up. One of the genes was altered. In genetics they speak about mutation factors, the herediting of the factor, the location of the altered gene at the chromosome...Some varieties are caused by one mutation factor. Other varieties are caused by a combination of more than one mutation factor. Every variety has his own genetical make-up.
Example: The development of the Lutino variety by mutation: A mutation factor (M-t+) caused the total loss of eumelanin in the plumage, horney parts and eyes.of the Bourke. The eumelanin production depends on the activity of tyrosine. Research did find to much activity of the tyrosine as the cause. This mutation factor inherits sex-linked. The mutation tooks place in in Holland in 1992 . The sex-linked mutation factor in the Bourke gave rise to the development of the Lutino and Rubino varieties..
ad 2.The second approach means: histological research
This approach starts first with the appearance of the bird species, the phenotype. The method is the observation and description of feather form and colour. The characteristic differences of the plumage are compared with the wild-form and other varieties of the same species. Every bird species has his own possession of colouring elements, pigments and feather structure. Also colour devision of the feathers and feather fields are important. .This is followed by the study of cross-sections of feather barbs.barbules and hooks, In this approch the starting point is the histology, study of the tissues of skin, horny parts and feathers. Histology is an essentional tool of biology. Histology is the study of tissue, sectioned as a thin slice, using a microtone. This slices are studied by the electronic microscope.
Example: The description of the Lutino variety: The total loss of the brown eumelanine means that there is a striking different colouring of the plumage.The presence of psittacine pigments, red and yellow, dominates the new coloured plumage in stead of the brown eumelanin. Because of the absence of the melanin the blue structure cannot express himself and a blue feather shall be white. Scientific research of the feathers lead to the conclusion that the cortex of the feather barbs which was filled by eumelanin before, is empty (white colouring) or filled with other pigments red or yellow psittacine (red or yellow colouring).
ad 3. Two kinds of namegiving of varieties
This two approaches can be used to naming varieties. In the scientific name the name of the mutation factor is used to point out how the genetical make up of the species is altered. Each bird species has his own specific genetical-make-up. Each variety of the species has his own genetical make-up The scientific name of the variety can be:Neopsephotus bourkii (M-t+) In this new name the name of the mutation factor has been put on.
The variety can be named after the new colouring of the species..In the common name the name of the characteristic colour is used to point out how the colour is changed. Each bird species has his own characteristic colouring. The common name is Bourle's parrot. In this case the name of the characteristic feather field of the variety refers to Lutino. (Lutein means yellow). The common name of the variety of the Bourke's parrot can be Lutino Bourke's parrot. In this new name the name of the new colouring has been put on.
The change in colouring and colour elements of the
wild-form as the starting point
This page will be dedicated to the second approach and gives information about differences in feather colour and feather structure and is based upon important reseach of feather colour in histological studies.
The Wild-type Bourke's parrot has several colouring elements. Eumelanin pigment, red and yellow psittacine pigments and some feather fields with structural feathers, feathers with a blue structure. The eumelanin of the Bourke is brown eumelanin. The Bourke's parrot is an exception to the rule that all parrot species have black eumelanin.
In practice the second approach starts with description and naming of the colours. The starting point is the new appearance of the species. Naming of varieties in this approach are based upon the colour of a feather field.or other distinctive characteristics of the new variety. The mutation breeder is mostly a good observer. Every hobbyist can easely inspect the birds and control the colour and the differences of the wild-form and the difference compared with the other varieties. It is a good custom to describe all the characteristics of a new variety carefully.
The scientific background of this approach is the histology. Study of feathers, feather colour, feather structure and feather development, based upon the histology, was done by Steiner, Auber, Beckmann and others. They studied the feather colours in parrots. Their work gave rise to a lot of information about the development of feather colours. The work of Steiner and Auber was the base of the description of all known varieties of the Budgerigar. It was a study ot tissues sectioned as a thin slice, using the microtone and the electronic microscope. Auber wrote that he did not choose the approach of genetics deliberately but preferred the approach of the histology. It was an immens and laborius work to make hundreds of drawings of cross-sections.of barbs, barbules and hooks of feathers and the tissues of the skin where the feathers were developing. Also a great number of feather germs of different stages of development was examined.
In this page I will start with some remarks about the origin of colours in the feathers because understanding of colours is an important resource to mutation breeding , namegiving of varieties and resolving of problems in practice.
An example of the tissue study of a green feather of a wild-type Budgerigar by Auber (1941), in a magnification x 1300, taken from a stage of the development of the feather. The outline of the cortex , the cell bounderies and grouping of melanin grains are visible already.
To understand how colour is arising from the structure of the feather,the presence.of pigments and changing of the feather colours in varieties, we can use a series of simplified drawings..We start with some technical terms.
Two types of feathers: We make difference between feathers of the common type and feathers of the structural type according to Beckmann. The difference between them is is the posession of blue-structure. The sketch I made is simplified but gives a good impression.
Feathers of the common type have only pigments as colouring elements. Feathers of the structural type have pigments and blue-structure. This combination of feather pigments and feather-structure gives the most varied colour possibilities as we see in the colours of parrots
Analysis of the feather barb of the common type of a wild-type Bourke compared with the feather barbs of three different coloured feathers: white, yellow and red.
Remark: There are two things that interests us, the colour of a single feather taken from the characteristic featherfield and a description of the plumage as a whole. of the variety. I am developing this approach to all varieties of the Bourke. The Lutino and Rubino are the first examples. The wild-form is the starting point.
:Comparision of the structure of a white, a yellow and a red feather with an original brown feather of the Wild-type.
This are simplified pictures of cross-sections of a barb of a feather taken from the back of the Bourke's parot. All drawings are feathers of the common type, without a blue-structure, brown (wild-form) white, yellow and red
The drawings are representing a cross-section of a feather barb of the back:of the brown wild-type and cross-sections of a white, a yellow and a red feather. Three pigments are involved in the plumage of the Bourke. The original colour from the back of the Bourke is brown. The brown eumelanin. is found in the cortex and in the medulla. The cortex is filled as a whole with brown eumelanin.. In the medulla the eumelanin grains are spread randomly. The colour of this feather is deep brown. In this feather there is no other pigment involved than eumelanin.
Colour development in new varieties
In 1992 a mutation did happen. This mutation brought a total loss of the eumelanin in the plumage in the cortex and the medula, but in the barbules and the hooks also. The colour of the original wild-type was altered totally. The loss of the brown eumelanine gave rise to other colouring of the feathers.The deposition of red and yellow psittacine replaced the eumelanin in the cortex. .The first new variety was the Lutino. Combination of the Lutino with other varieties who had a lot of red pigment brought into being.the Rubino variety.
Extension of red and yellow pigment by selection
History: What happened between the early days of import of the Bouke in Europe in the ninetheens century ? Origenally there was no red or yellow pigment in the back. The only pigment in this featherfield was the brown eumelanin. The first mutation brought the pastel variety. This variety was developed. in1954. This mutation deminished the eumelanin. All breeders were busy to realise a Bourke's pastel variety that was as yellow as possible. This was the reason that the yellow pigment was extended in the wings, the whole back and the tail. The cinnamon variety was developed in 1959. The cinnamon was a variety that was more rose-brown. A lot of breeders were dreaming of a red coloured Bourke. Among them was Goossens.He selected Bourke's with a lot of red pigment.in the front and back. In 1972 he was very lucky. He bred from a combination of a Cinnamon hen and a Wild-type cock the first Rosa Opaline variety of the Bourke.It was a hen.The result of the combination of this two varieties, followed by a strong selection, did keep free the way to a Rosa Opaline variety. with a big extension of the red psittacine pigments in upper and lower back, wings and tail.This happened after decades, long before the lutino and rubino varieties did appear.
Remark: The loss of eumelanin pigment in the cortex makes place to other pigments, yellow or red psittacine pigment. A yellow feather drawing (2) or a red feather drawing (3) can be the result. This depends on the possesion of other pigments in this feather
Lutino and rubino varieties
Comparison of the plumage of an Albino, (alba=white), a Lutino (lutein=yellow) and a Rubino (ruby= red) with the brown Wild-type
Albino? We did speak above about a white feather, not about a whole white plumage. The Albino is a dream of every Bourke's breeder. This M-t +mutation is a melanin mutation . A full white plumage is only possible when there is a total loss of the other pigments also.. An Albino in most parrots species needs a combination of two mutations, total loss of melanin (M-t) and a total loss of psittacine pigments (P-t P=psittacine, t= total loss).The Albino did not appear in the Bourke varieties.thusfare In other birdspecies, like the Blackbird, one mutation (M-t) is enough, because this species has only melanin pigment and has no other pigments.
Lutino and Rubino: Plumage description: Disappearing of the brown colour because of the loss of all eumelanin pigment. Also disappearance of the blue colour because of the lack of melanin.in the medulla. White colour is replacing the blue colour. Disappearance of the rosa colour because the combination of brown and red pigment was no longer possible..Intensive red or yellow colours are possible because of the extension of red or yellow pigment.by replacing the eumelanin in the cortex.
Differences and similarities of Rubino and Lutino varieties. The head and hindneck are red and white in the Rubino and partly red and white in the Lutino. The outer vanes of the flight feathers and tail are white in both varieties.The Rubino has red tail feathersa, red upper and lower back, red wings, except of a yellow band on the wing. The Lutino has a yellow back, wings and tail. The breast and belly are red in both varieties. The most important differences between rubino and Lutino are the upper and lower back and wings.
Question: Why are the colours yellow or red so bright? The Wild-type Bourke has brown eumelanin. The red and yellow colours are bright because there is no mix of yellow and brown (sand coloured brown) or a mix of red and brown ( rosa) This bright colouring arrives when the amount of eumelanin grains in the cortex and medulla is totally gone.
Question: Where does the red back and tail comes from? By mutation, a combination of the Lutino and the Rosa variety? Or by selection of partners with a lot of red pigment in the plumage? Or both?
In the beginning the Lutino was combined with all other varieties and the Wild-type. Some of them had a lot of red pigment also. It was easier to combine the Lutino to recessive varieties than to sex-linked varieties. The problem of the combination of the Lutino with the Rosa Opaline is the fact that both mutation factors involved are inheriting sex-linked .Crossing over is needed. Many breeders preferred a combination with the Wild-type with a red belly or with other varieties with a lot of red pigment in the plumage.. This means that not every Rubino was bred from the combination of the Lutino and the Opaline variety.
Remarks: The red and the yellow psittacine pigment are inheriting independently,. Research let to the conclusion that red an yellow psittacine pigments have a different chemical make up..My experience is that most of the mutation factors are melanin mutations, I discovered in many years of breeding that all varieties based upon melanin mutations, a red and a yellow variety are possible.
Par example: I bred the Red Opaline and the Yellow Opaline, the Yellow Pastel and the Red Pastel, the red Edged and the Yellow edged, the Red opaline-Pastell ( in German Lachs) and the Yellow Opaline-Pastell, the Sandcoloured Fallow and the Red Fallow, the Wildtype Pied with red and with yellow feathers, Thusfare there is no study about the turn from yellow to red and reverse.. Steiner reported the possibility of the total loss of one of the pigments red or yellow and the preservation of the other pigment in the plumage. What we saw thusfare was a reverse of colour in the back, wings and tail.
Question: Why are there Lutino's and Rubino's with colours that are faded in stead of intensive? When the amount of psittacine pigments is low. and the cortex is not enough filled with pigment than the colours are faded. Selection is the only answer.
Question: What will be the result when we combine a Lutino variety with a Rubino variety? Both have the same mutation factor. Both did loose all melanin. The only difference is the kind of psittacine pigment that fills the cortex. There will be a mix of the two pigments in the cortex . In this case there will be a red suffusion (1) or .some feather fields have red pigment in the cortexother feathers have yellow pigment in the cortex The result is a multicoloured variety. If de feather has yellow pigment or a mix of both pigments is decided in the zone of differentiation iunder the growing feather.
Two variances on the thema red and yellow
In mutation breeding of this varieties of the Bourke's was to little attention paid about breeding full red or full yellow varieties.
Copyright 2008 by Bob Fregeres