Genetic of the canary and canary-like species. Parts 1 to 3
Our country has contributed along the history with uncountable zoological species that one time selected and improved has been the base of different avian activities and livestock.
One example of this is the canary (Serinus canaries) which from the XVth century has spread to the whole world constituting nowadays, not only a hobby for lots of people, besides also an economic activity of rising importance.
For this reason and as a member of our native wildlife we have considered of interest realize a study about the genetic structure of the canary and canary-like species.
This present work shows the scheme of the known genes and their chromosomic distribution doing if itâ€™s possible a quantification of each.
Material and methods
We have worked with the data obtained during 20 years in our breeding places as well as in others owned by differents societies of Canary bird breeders and specially in Ornithologic Society of Reus.
The methodology consists in achieve all the possible combinations with the aim that each character manifests in an homozygote state and in their corresponding carriers.
Sometimes there are difficulties because of some combinations that originate canaries with low vitality and in consequence the study of some characters isÂ difficult. In all the cases we have tried to quantify the observations.
The canary possess nine pairs of chromosome presenting two X chromosomes the males and only one the females.
In general asÂ master line we have demonstrated that the autosomic inheritance is integrated by genes of productive character, and the inheritance sex-linked ensures the fixation. The following we described each gen.
I. Autosomic inheritance.
Itâ€™s integratedÂ by genes distributed in 8 pairs of autosomes and regulates the somatic characters as well as the collaboration, the singing and the feather.
1. The PMP gen controls the production and oxidation of the melanines in the feather. We considerÂ inside it a producer loci of brown melanines, their absence originate the opal mutation and another producer of blue melanines that their absence produces the rubino mutation. Both opal and rubine are recessives versus the normal gen.
This gen has to be autosomic because of the crossing between a melanic bird and an amelanic results in a 100% of pied sons and if this producer was in the X chromosome a melanic male crossed with a amelanic female would result inÂ melanic and pied sons.
2. The PMO gen governs the production of melanines for the eye.
Amelanic birds in relation to the feather manifest melanines in the eyes, we could think that it can be thanks to a lack of fixation. However, the study of the canaries â€śIsabela Opalâ€ť demonstrate that these birds having inhibited the production of their single brown melanine, they can manifest it in the eye. For this reason we consider that the producer center of melanine for the feather and for the eye are different although they are close because of the rubino mutation affects both. The rubino character is recessive in relation to the normal.
3. The C gen determines the category.
This gen regulates the size and the structure of the feather therefore the lipochrome pigments are more or less blurred originating the snowy and intense birds. The intense character is dominant over the snowy and the ancestral. Like all the dominant characters, over the original type, affects the vitality of the homozygotes.
4. The A1 gen.
Regulates the capability of absorption of the carotenoid substances (lipochrome pigment). The wild canary presents yellow lipochrome but the hibridation with â€śCardenalito of Venezuelaâ€ť has introduced the red lipochrome. The inhibition of this gen correspond to the denominated: white or recessive silver, that presents also strong visual deficiencies and it acts like a recessive versus yellow or red.
5. The PB gen.
Determines the production of the White or dominant silver that it can be considered like the lipochrome.
This character dominate the colour of the ancestral AL gen both yellow or red, like all the dominants over the ancestral affects the vitality of the homozygotes.
6. The S gen
It is a group with aleatory character that governs the somatic characteristics. In this group we include the production of type canaries (Gibber Italicus, Dutch, Raza EspaĂ±ola), canaries of big sizeÂ (Yorkshire), head morphology, singing capability (Seifer, Roller, Malinois, etcâ€¦)
7. The M gen.
Producer of puff that is dominant over the ancestral and affects the vitality of the homozygotes.
8. The Co gen.
Regulate the apparition of melanic or amelanic crowns and is a characteristic of breeds like Lizzard.
II. SEX-LINKED INHERITANCE
How we indicated regulates basically the fixation of substances regulated by the autosomic inheritance.
1. The T gen.
It determines the birds type, by regulating the fixation of melanins in quantity, quality and distribution among concentric areas of the feather.
The ancestral type of all the canaries and finches correspond to the black-brown that is fixed full to blue and brown melanins. By losses in the capability of fixation quantitative and qualitative have been produced the three types: agate, brown and isabelas that are considerated as classic types.
The four types present a distribution of melanins in three zones. The pastel mutation besides affect the fixation of brown melanins alters the zonal distribution and complementarily the satined mutation originates the lack of fixation of blue melanins.
Furthermore the two mutations described present two phenomenons noteworthy: atypic birds and black-brown crossingover.
Melanic atypic canaries have PMP autosomic genes that provide excessive or very low melanins in relation to their fixation capability. For example, a canary capable to produce blue melanins ifÂ fixes brown (Isabela) will be an atypic.
Another case of atypical is observed in the carriers males of satine or pastel because they produce but they canâ€™t fixed. In the other hand the carriers of opal or rubino because of they are autosomic they are not distinguished of the normals.
The black-brown crossingover produces only in male agate sons and browns. This is because the capability of fixation of both types is equal to black-brown. However the confirmation of the crossingover is obtained only when we obtain black-browned descendents of the same and with this we check the pass of a piece of chromosome to another.
2. The FLP gen.
It regulates the fixation of lipochromes in the feather in the quantitative and qualitative aspect. From a quantitative point of view the FLP gen can be normal or ivory. The last one fixed 50% less than the normal, obtaining a lightest colour.
From a qualitative point of view the FLP gen can considered that divides the feather in two fixation zones. If the FLP gen has a dimorphic character the lipochrome appears only in shoulder, eyebrows, chest and rump giving to the bird a poor colour and for this reason it permitting a best camouflage of the females and the nest.
The FLP gen can be not dimorphic permitting the fixation of the lipochromeÂ along the wide of the feather and then the colour intensity depends exclusively of the G gen (category), their autosomic inheritance has already been studied.
Thus canary breeders consider three united categories: dimorphic or mosaic, intense and snowy, from the genetic point of view these characters depend on two genes and they have a clear ecologic finality of camouflage versus predators.
Furthermore of the described characters there are other types less studied like madrone, champignon and sequin (autosomic) of goldfinch as well as the crown of Lugano. Special mention to the red colour in the chest and in the head of the linnets also because it is a sex-linked character andÂ involving nutritional, stational and nervous factors.
Currently weâ€™re working in a project that consists in hybridize some species with genetic compatibility. â€śVerdecitoâ€ť, â€śCardenalito Magallanesâ€ť, â€śCardenalito CĂłrdobaâ€ť, â€śCardenalito de Venezuelaâ€ť, â€śMozambique canaryâ€ť that are some of these species. We pretend to give you all the genetic information related to the canary raised in captivity as well as try to search an individual with fixed characteristics and it could be equal to the specie that originated the others.
We consider that genetic studies constitute the more important base in the knowledge of any specie and it’s necessary in birds that form our native wildlife. From these studies we obtain benefits not only in the improvement, creation and pureness of different types, varieties and categories if not itâ€™s also applied the genetic to the study of the nutritional needed of the birds.
From these knowledges we will govern the scientific characters of the industrial breeders of canaries and canary-like species.
Following we emphasize these important conclusions:
1. The autosomic inheritance governs the productive parameters.
2. The sex-linked inheritance controls fixation characters and has an important mission in the camouflage of females and visibility of males.
3. Most produced mutations studied (satine, pastel, opal, rubino, ivory) have recessive character versus the normal because they consists in the disappearance or block of the existent genes or part of the same.
4. Some mutations (puff, dominant white, intense) are dominants over the original genes affect the vitality of the homozygotic birds.
5. It doesnâ€™t know until now any sex-linked mutation or with dominant character, contrary to the terms used by canary breeders that confusing sex-linked inheritance with dominant character and autosomic inheritance with recessive characters.
6. Genetically itâ€™s not correct the denomination melanic and lipochrome to distinguish birds with or without melanin in the feather. The correct term is melanic or amelanic because of lipochromes are all except recessive whites.