COLOR INHERITANCE AND GENETICS

ONLINE TRANSLATED *WILL BE UPDATED SOON


Topics of this subpage:

  • Color inheritance in Degus
  • Color genetics
  • Consequences of "breeding" without knowledge of genetics - color breeding

 

COLOR INHERITANCE

The inheritance of genes from one generation to the next is not arbitrary and accidental, but is subject to fixed rules. In the middle of the 19th century, the Augustinian monk Johann Gregor Mendel was able to prove these laws of inheritance for the first time through experimental attempts at crossing them with the garden pea. In 1865 he published the results of his cross-breeding experiments in his work " Experiments on Plant Hybrids ".

 

From the results of his experiments, Mendel derived the 3 "Mendelian laws" of inheritance, named after him. Mendel's laws are universal in character, they apply to plants and animals. Mendelian rules describe the inheritance process for traits whose expression is determined by only one gene becomes.

 

Download
Color inheritance at Degus as a table | V2.0 *only in German
A summary of color inheritance, results of each pairing of different colors and their inheritance.
➔ Agouti-based colors only, please contact us personally for all non-agouti colors.
Farbvererbung bei Degus_Dein-Degu.de.pdf
Adobe Acrobat Dokument 180.8 KB

COLOR GENETICS

The genotype is the totality of all genetic make-up of an individual, the phenotype is the external appearance.

 

A LOCUS / A (AGOUTI)

The A locus decides whether agouti fur or non-agouti fur, it forms the basis for all other colors.

 

Genotype AA or Aa: wild animals

Genotype a / a: black animals

 

Genotype A / AD / DE / E or A / - D / - E / -: (Agouti homozygous)

A degu has the allele combination D / D at the D locus and the allele combination E / E at the E locus, ie the fur does not show the colors specified by the D&E locus in the pigmented areas.

  • The animal carries the normal allele A / - D / - E / -. The system for the coat color (blue agouti / blue or red, sand, cream) is not available. It is an agouti degu without color carrier properties.

 

B-LOCUS / B (CHOCOLATE BROWN)

The B locus creates the color (s) chocholate / chocolate brown / cinnamon and, in combination with other Loki, other colors. In order for this gene location to have an influence on the coat color, it is necessary that at least one E allele is present at the E gene location.

 

Genotype B / B: (no chocolate degu or chocolate carrier)

A degu has the allele combination B / B at the B locus, ie the fur does not show the colors specified by the B locus (chocolate, cinnamon, brown) in the pigmented areas.

  • The animal is pure-blooded carrier of the normal allele B. The system for the coat color chocolate / cinnamon is not available.

 

Genotype B / b: (Schokoträger / SchokoT)

A degu has the allele combination B / B at the B locus, ie the fur does not show the colors specified by the B locus ( chocolate, cinnamon, brown in the pigmented areas .

However, there is a 50% probability that he will pass on the system for these coat colors to his offspring.

  • The animal carries the allele b, which is responsible for the coat color chocolate / cinnamon, and the normal allele B. Because of the recessive inheritance, the animal itself does not develop the coat color chocolate / cinnamon. The plant for the coat color chocolate / cinnamon (b) is passed on to the offspring with a 50% probability 

Genotype b / b: cinnamon or brown animals

A degu with the allele combination b / b at the B locus means that the degu cannot store black pigment (eumelanin) in the hair, but only lighter pigment (the so-called pheomelanin). 

  • The animal is a true carrier of the chocolate / cinnamon allele responsible for the coat color b. The plant for the coat color chocolate / cinnamon is passed on to the offspring with a 100% probability. 

 

C-LOCUS / C (COLOR)

The C locus suppresses the formation of all pigments and thus creates albinism and all variations that are formed with the help of the C locus and corresponding other genes.

 

Genotype c / c: albinotic animals

 

D-LOCUS / DILUTION (colour THINNING)

The D-Lokus creates the color (s) blue, blue (agouti) and, in combination with other Loki, other colors.

 

Genotype D / D: (no blue degu or blue carrier)

A degu has the allele combination D / D at the D locus, ie the fur does not show the colors defined by the D locus (blue agouti, gray, silver) in the pigmented areas.

  • The animal is a true carrier of the normal allele D. The system for the coat color blue agouti / blue is not available.

 

Genotype D / d: (blue carrier / BT)

A degu has the allele combination D / d at the D locus, ie the fur does not show the colors defined by the D locus (blue agouti, gray, silver) in the pigmented areas.

However, there is a 50% probability that he will pass on the system for these coat colors to his offspring.

  • The animal carries the allele (d) responsible for the coat color blue agouti / blue and the normal allele D. Because of the recessive inheritance, the animal itself does not develop the coat color blue agouti / blue. The predisposition for the coat color blue agouti / blue (d) is passed on to the offspring with a 50% probability.

 

Genotype d / d: (blue degu)

A degu with the allele combination d / d at the D locus, ie the fur has the colors defined by the D locus (blue agouti, gray, silver) in the pigmented areas.

  • The animal carries the allele responsible for the blue agouti / blue coat color (d). The predisposition for the coat color blue agouti / blue is passed on to the offspring with a 100% probability.

 

E-Locus

The E-Lokus creates the color (s) sand, red and in combination with other Loki other colors.

 

Genotype E / E: (no sand colored degu or sand bearer)

A degu has the allele combination E / E at the E locus, ie the fur does not show the colors defined by the E locus (red, sand, cream) in the pigmented areas.

  • The animal is pure-blooded carrier of the normal allele E. The system for the coat color red / sand is not available.

 

Genotype E / e: (sand carrier / ST)

A degu has the allele combination E / e at the E locus, ie the fur does not show the colors defined by the E locus (red, sand, cream) in the pigmented areas.

However, there is a 50% probability that he will pass on the system for these coat colors to his offspring.

  • The animal carries the allele e, which is responsible for the coat color red / sand, and the normal allele E or EM. Because of the recessive inheritance, the animal itself does not develop the coat color red / sand. The predisposition for the coat color red / sand (e) is passed on to the offspring with a 50% probability.

 

Genotype e / e: (sand colored degu)

A degu with the allele combination e / e at the E locus means that the degu cannot store a black pigment (eumelanin) in the hair, but only a lighter pigment (the so-called pheomelanin). This pheomelanin can have all possible shades of color from reddish to yellowish to whitish-cream.

  • The animal carries the allele E, which is responsible for the coat color red / sand, and there is a 100% probability that the offspring will inherit the predisposition for the coat color red / sand.

 

DOMINANT-RECESSIVE INHERITANCE

THE MENDELian RULES

Mendelian inheritance is a type of biological inheritance that follows the principles originally proposed by Gregor Mendel in 1865 and 1866, re-discovered in 1900 and popularised by William Bateson. These principles were initially controversial. When Mendel's theories were integrated with the Boveri–Sutton chromosome theory of inheritance by Thomas Hunt Morgan in 1915, they became the core of classical genetics. Ronald Fisher combined these ideas with the theory of natural selection in his 1930 book The Genetical Theory of Natural Selection, putting evolution onto a mathematical footing and forming the basis for population genetics within the modern evolutionary synthesis.

Please read the article for further understanding.

Degus therefore have the dominant recessive inheritance. In the dominant-recessive form of inheritance, the dominant allele prevails over the recessive allele. The genotype is the totality of all genetic make-up of an individual, the phenotype is the external appearance.

 

In dominant recessive inheritance, all members of the F1 generation have the same phenotype as one parent.

 

Example: In degus, the agouti coat color is dominant compared to the blue / sand-colored, the system for the blue / sand-colored coat color is therefore referred to as recessive. When pure-bred agouti and pure-bred blue / sand-colored individuals are crossed, all members of the F1 generation have inherited an allele for the blue / sand-colored coat color and an allele for the agouti coat color, they are heterozygous. Nevertheless, they all have the agouti coat color because agouti is dominant over blue / sand colors.

 

The rule of division or segregation applies when two individuals are crossed who are both heterozygous in the same way, e.g. B. two degus who have genes for the blue or sand-colored coat color. This could be the F1 generation from the previous section. In descriptions of the Mendelian rules, the offspring of such a heterozygote cross are therefore referred to as grandchildren or second generation of branches (F2). The offspring from this mating are no longer uniform with one another, but split up in terms of both genotype and phenotype.

 

  • If the inheritance is dominant-recessive, then on average a quarter of the F2 individuals are pure-bred with two recessive genes and show a corresponding characteristic expression (e.g. blue or sand-colored). The other three quarters show the dominant-recessive inheritance phenotype. These three quarters are made up of pure inherited (one fourth) and mixed breeding (two quarters) individuals. Overall, there is a ratio of 3: 1 in the phenotype and 1: 2: 1 in the genotype.

 

CONSEQUENCES OF "BREEDING" WITHOUT KNOWLEDGE OF GENETICS - COLOR BREEDING

GENETIC MALFORMATIONS DUE TO IGNORANCE

The first real color mutation occurred around 1998 in Holland with the so-called silver degus or blue degus (Sporon A., Mettler M., 2002). 

 

This increasing popularity had other unpleasant consequences: DIY stores added degus to their range and due to the constant increase, blue color mutations soon accumulated. Not only is the demand for colored degus growing, but piebalds are also moving more into the focus of the desires of ignorant pet owners.

 

Most people are probably not aware that especially with such color mutations an increase is promoted, which could have negative consequences on the health and the character of subsequent degugenerations. Many breeders or "I once wanted degu babies because my degus are so great - multipliers" strive to combine their characteristics by crossing animals of different colors, e.g. B. to combine the color scheme with another color scheme. However, this not only requires careful planning about which animals are to be mated with each other, but also basic knowledge of so-called "classical genetics".

The consequences of such breeding with poor selection (or with wrong breeding priorities) will have to follow. Lower life expectancy, hereditary diseases and poor social tolerance among conspecifics could be possible consequences. 

  

Genetics is the science that studies how certain traits, i.e. the genes that are responsible for the expression of these traits, are passed on from one generation to the next and how the information encoded in the genes is implemented.

 

Too much kinship can be fatal. When siblings, cousins have offspring, they are usually more susceptible to disease, less fertile and more often malformed. That inbreeding leads to more diseases and infertility is known from laboratory tests and animal breeding. It is not without reason that zoological gardens risk public displeasure and kill animals rather than allow close relatives to mate.

 

Inbreeding damage

  • weaker immune system
  • smaller size
  • refined bone structure
  • sparse hair growth
  • Loss of pigment
  • decreased sex drive
  • infertility
  • delayed development of offspring
  • missing sockets
  • pronounced glaucoma formation
  • Balance disorders

Conclusion:

 

That especially with color mutations in which an uncontrolled reproduction is promoted, can have negative consequences on the vitality and the character of subsequent deguge generations. The consequences of such breeding with poor selection (or with wrong breeding priorities) can only be guessed at. Lower life expectancy, hereditary diseases and poor social tolerance among conspecifics could be possible consequences.

 

Susceptibility to diseases or inherited genetic defects are not caused by the color of the coat but by inbreeding, incorrect nutrition, incorrect husbandry and insufficient selection of the parent animals - it is therefore a misconception that the coat color has an influence on health.

 

Targeted promotion of serious breeding, which is based on healthy breeding lines and through appropriate, solid specialist knowledge of the breeder, which is not only based on forum knowledge and information from the Internet, but mainly on the experience of professional breeders and specialist literature, enables the chance to establish healthy breeding lines . It becomes clear that without knowledge of heredity, genetics, etc., breeding should be left to people who are familiar with genetics and who keep their animals in a species-appropriate manner. 

 

BIBLIOGRAPHY & RECOMMENDED LINKS ON COLOR GENETICS

ratfrett.jimdo.com -- Seite zur Farbgenetik (German)

Mendelsche Regeln (Wikipedia)

degutopia.co.uk -- Sehr informative Seite als Einstieg (English)

 

All texts and contents are subject to copyright, © dein-degu.de