Domestic rabbit#Genetics

The genetics of the domestic rabbit in the sense of pedigree rabbits breeding is mainly concerned with the inheritance of external, breed typical features, especially the coat color, hair length and hair texture and body size of the domestic rabbit.

The inheritance of these characteristics was studied before the discovery of the structure of DNA by breeding experiments. The corresponding nomenclature dates from that period, but, as practically handled well, still used by breeders and in the relevant literature in this form.

• 4.1 Long Hair Factor
• 4.2 Short coat ( Rexes )
• 4.3 Satin
• 4.4 Other structures in the rabbit hair 4.4.1 beard rabbit
• 4.4.2 Possum

The Erbsymbole and Erbformeln

Due to the work of Nachtsheim, who conducted appropriate investigations in the thirties in Germany, in Germany a different name from the international use of the so-called genetic markers will be used. The international ( English ) nomenclature has not been successful in Germany, although their use would also be in terms of comparability with other species of advantage. In this article, the German nomenclature is also used, given the international parallel. For other species (cats, dogs, Color mouse etc ) homologous mutations are observed there, the English nomenclature is used in most cases. The various genes responsible for coat color are marked with letters, with dominant alleles with large, recessive alleles are indicated with lower case letters ( see also Mendelian rules). The genotype of the animal is usually given in the form of a break, there are inherited from the parent gene variants in the counter, inherited from the father in the denominator., By comparing the dominance of the individual alleles are predicted known genotype of the parents provided the coat color and hair texture. For the sake of clarity, the fraction notation is only used when Spalterbigkeit to be specified, unless otherwise indicated, after the slash symbol is called the English.

Staining of the wild rabbit

The color of rabbit fur is determined by three color zones as sub -, intermediate and top color is visible when blowing into a correspondingly dyed rabbit fur. The difference in coloration of the domestic rabbits is determined by whether this zoning is formed at all and what pigments are present in the individual zones. In the wild rabbits bzw.wildfarbigen house rabbit finds a dark blue sub- color and a gelbräunliche intermediate color. Black, brown and yellow hair tips are the top color. The belly and underside of the bottom of the flower are bright with blue belly under color, the ears are a dark edge edged ( agouti badge). The coloring of the wild rabbit meet the gray rabbit breeds (eg Grey Giant, Gray Wiener hare in gray colors shock).

Inheritance of coat color

The author Dr. Gerhardt Hochstrasser, Würzburg, has ( following the German system ) made ​​to the development of this symbolism and succeeded in some cases show that the previously expressed opinions are not necessarily applicable. In following his views and comments are given in parallel with the conventional understanding.

Albino series

Albino series A (C) is the basic factor of the pigmentation of the hair. Animals with this gene in the wild type have the full ability to form pigment. The individual mutations of this gene lead to a decreasing pigmentation of the coat. This is due to the formation of the enzyme tyrosinase. The increasing loss of color is particularly evident when one considers the gradation of staining in wild -colored animals, ie wild rabbit coloring -dark Chinchilla Chinchilla Chinchilla Colored marten Wild Colored Russians rabbits ( chinchilla colored badge ) albino. The various stages of the gene mutation embody different loss levels of this enzyme, the partial loss (dark chinchilla, chinchilla, marten ) on the heat-labile form ( Russians drawing) until the complete loss ( albino). For a detailed account see albinism. Accordingly proposes Hochstrasser before to call this factor " maximum presence / absence of tyrosinase maximum ".

The first stage of this gene mutation is the factor for dark chinchilla ad ( CCH3 ). In Germany no rabbit breed with this factor is known, it is ash-gray animals that are darker than the standard chinchilla. The Dark Chinchilla factor is recessive to wild-type (A / C), but dominant over the remaining variants of the albino series.

The Chinchilla factor achi ( CCH2 ) takes its wearer to the fact that the yellow pigment ( pheomelanin ) is not formed of the wild rabbit fur, instead of the yellow color occurs between a pure white band, the fur of the rabbit thus appears bluish- ashen. The claws are dark horn color. Due to the similarity of this coat color with that of the South American chinchillas was the naming of the breed. Typical representatives of this mutation type are the large and small chinchilla rabbits.

The Marder factor on is also not recognized as the sole factor in Germany as a single race. Standard compliant marten rabbit (type marten ) are spalterbige animals which are obtained by crosses between Russians rabbits with the homozygous, so-called dark martens. This makes it clear that this mutation together with the Russians factor and the albino factor shows an intermediate pattern of inheritance. The breed animals no zoning of coat colors more is additionally provided by the lifting of the agouti factor (g / a instead of G / A). The Marder factor is reflected in the coat color of a darker coloration of the head, ears, limbs and tail ( flower), a broad strip of the back is also darker. The bottom color of the fur is combined bläulich.Ist the marten factor with the agouti cofactors arise by means of Chinchilla marten. Genetically to the marten rabbit include the Siamesenkaninchen, subscribe to these animals is that of the famous Siamese cat, with a bright, bright yellow color when Gelbsiamesen deck, shoulders and rear portion are slightly darker. The Siamkaninchen have a dark, eyes full snout (mask, dark ears and legs, the flower is also dark).

The Russian factor ( on or cH ), referred to in English as Himalayan, causes some albino animals with red eyes. Only the muzzle, ears, legs and flower are colored ( Akromelanismus ). When derived from the wild- type mutation color the flowers underside is bright to the standard appropriate animals show plain black, blue, or brown markings. The dark color of the extremities is caused by so-called Kälteschwärzung. Only the parts of the body, where a skin temperature of less than 35 ° C (other details 28 ° C) there is, forming a color. The reason for this is that when the affected animals, a heat-labile form of tyrosinase is formed. For this reason, show Russians and Californians even when kept outdoors in winter a better drawing than in summer, with special cold formed, especially in older animals also have a dark zone around the eyes, in the does well on the dewlap from. If an animal shorn with Russians factor in the winter part of the coat, dark hair grows there, the resulting stain disappears at the next molt. The young animals of those breeds are born pure white, the formation of the drawing takes place only after leaving the nest. Are the pups exposed during lactation cold, often produces a gray approach of the coat, which disappears when moulting.

The final stage of the albino series is the albino factor (a or c). Animals that have this gene, do not form pigments, since they completely lack the tyrosinase. The skin thus appears pure white, as well as the iris of the eye is not colored, the eye appears red by the shining through the blood vessels of the fundus. Typical representatives of this type of mutation are the New Zealand White and the ermine roach.

Black series (B bzw.E series)

The called in German with B in the international literature with E ( for Extension locus ) gene controls the expression of the black pigment eumelanin in rabbit hair. Mutations of this gene cause according to reinforce or dilution of black in appearance.

Dark Iron Grey ( Bee or ED ) and iron gray ( or Be There ) are mutations that show compared to the wild type (B or E) a dominant inheritance. The animals show the agouti badge, but are much darker in color, dark iron-gray animals are almost black. Grey iron animals possess the whole body a dark body color, the belly color is only slightly brighter. The intermediate color and neck wedge are only hinted at. While dark iron gray is approved in Germany in any race as a color punch, iron-gray animals are permitted as color varieties, for example, the German giants, the horror Vienna and gray colors dwarfs. Dark iron gray is dominant over iron-gray, both of which are intermediate compared to the wild type. (see also the suspected Hochstrasser Black amplifier factor)

The wild-type B / E is responsible for the normal expression of the black pigment in the coat. In combination with the wild type, the other Farballele results in the wild gray rabbit fur. This coat color is found in all wild gray coat colors. It must be noted at this point that in practice, the breeder gray color varieties are not kept separate in the necessary degree, the ambiguities and transitions are possible. (see also yellow and black amplifier series )

The coloring of the Japanese rabbits ( English: Harlequin ) ( bj or ej ) ​​also provides a mutant of the Black Series dar. In this mutation, the black pigment is unevenly distributed in the coat, so the result is a black-yellow pied fur. The distribution of the spots can be used both in a small distributed structure occur ( realized in the Rhön rabbits there as white spots because in combination with the chinchilla factor ) or larger color swatches, as in the standard contemporary Japanese rabbits. The original version ( Japanese factor combined with the wild-type alleles of the other ) were also gray white spots on the appearance of the animal. However, White has been largely replaced except for the belly color, one strives today in genotype animals with the combination of the Japanese factor and the Einfarbigkeitsfaktor ( g or a) to. The Japanese factor behaves recessive to wild type.

The final stage of the B and E series represent yellow colored wild animals (c / s ), which are approved as color impact in some breeds. This mutation is in combination with other factors such as Burgundy rabbits ( y1, according to Dutch standard without additional amplifiers yellow ) or Red New Zealanders ( y1. .3 ) with additional yellow amplifier, or as yellow silver with additional silvering of the coat (P1 ... 3/Si ) involved. In combination with other color factors c / s also the drawing of various other breeds involved (eg in Thuringia together with g / a).

Black pigmentation (C / B series)

By this gene, which determines the system of the black pigment, in addition to the wild type ( C or B ) is known, the mutation of the absence of the black pigment ( c and b). In this case, a brown -colored wild beast, that is, the zoning of the color distribution in the hair remains, however, the animal appears brown. In combination with the factor -, in combination with the silver factor ( P1 ... 3/Si ) ( g or a zoning of the hair removed, the uniform brown color of the Havana Rabbit arises ) the color of brown silver rabbit.

The parallel genetic locus in humans caused Oculocutanen albinism type 3, also known as brown locus and is described in the article albinism.

Density of pigmentation D / D

This factor, which is referred to incidentally in the German and the English symbol system with D ( for the Dilute gene) (on double symbolism is therefore omitted here ), determines the density of the pigments in rabbit hair. Its mutation to d causes ( due to irregular breakdown and clumping), a dilution of the pigment and a change in skin color to blue partridge. This color show as the Perlfehkaninchen and the Blue-gray Vienna. If this mutant with the loss of color zoning combined ( g or a) creates the lush blue color of the Blue Wieners. Come to that the mutant c (or b ) is reached, the light blue color of the Marburger Feh.

The agouti factor ( agouti )

The Wild Farbigkeits or Agoutifaktor (G or A) determines the area distribution of the pigments in the hair. The English name of this factor is derived from the agouti.

Is the agouti factor in its original form G / A is present, the animal shows the typical agouti Features: Three-zone color distribution of hair on the back, as well as the typical agouti badge: White belly - and flowers base, inside of the thighs and Jawed edging and brownish neck wedge. The speckles on the back Color continues as a black and white speckled top continues on the flower. Is the agouti factor with mutations of the other Farballele combined, the result is the drawing images described therein.

The first mutation step of the agouti factor is the Lohfärbung (English tan, symbols or go at). In this mutation, the zoning of the hair is removed, all the other Farballele present in the wild type, resulting in a black coat color. The lighter agouti badge remain as white or cream-colored markings. In this form, the tan is not represented as colors shock, the Lohkaninchen also have the yellow amplifier ( y1. .3 ), which lead to a bright yellow to red abdomen lower color. In combination with the chinchilla factor ( achi / CCH2 ) the drawing of Weißgrannenkaninchens arises. After Hochstrasser this factor instead Lohfaktor should be better called " badges maintenance factor " as the typical to this mutation, the preservation of the agouti badge, while the the Lohkaninchen distinctive yellow-red tan is caused by the action of yellow amplifier.

In state g and a is the zoning of the coat color is completely removed, the rabbit is monochrome. In combination with the other alleles in the wild type result only black animals (Alaska, Black Wiener). Mutation of the remaining color factors leads to increasingly lighter colored, plain animals, from the blue of the Blue Wieners ( ABCDG / aBCdeE ) over the lighter blue of the Marburger Feh ABCDG / ABCDE, the color of the sand Separatorkaninchens ABCDG / ABCDE.

Silvering

Under silvering is defined as the occurrence of individual, more or less uniformly distributed in the coat hair with pigment -free top, give the fur along with the regular, black tipped guard hairs like a silver, frosted appearance. Young animals of the breeds are born without this silver treatment, it appears during the first year of life with the hair changes. The mutation (P1 ... 3 / si) is dominant over the Nichtsilberung ( p / Si). The silvering is described one of the oldest known mutations in the rabbit and already in English writings from the 17th century. The inheritance of silver treatment is not fully understood ( Sandford ).

Spotting

There are at least two different alleles that determine the spotting of rabbits. A distinction is made between the Punktscheckung, as with the German giant piebald or skewbald English. A different type of spotting is the belt or Plattenscheckung that occurs in the Dutch rabbit.

The two factors differ in their effect, while point check factor acts by during embryonic development occurs " too late " migration of melanoblasts from the neural crest, with no incorporation into the hair roots can be more than melanocytes by the now incoming hardening of the skin layers and the hair remains colorless accordingly. In contrast, under Plattenscheckung remains by superficial defects of neural crest formation of melanoblasts that otherwise, the blood vessels following immigrate to the skin surface and thus the hair roots and perform there as melanocytes, the pigment formation.

Punktscheckung

Punktscheckung ( German symbols k / K, English symbols en / En) is evident in homozygous form by a little animal drawn, the light check in so-called, which is essentially white with only a little darker drawing ( breeder expression: Chaplin ). The mutation for spotting ( K or En) shows an intermediate pattern of inheritance with the wild-type k / s. In the approved standard breeds Punktscheckung is always in combination with monochrome, one exception is the Rheinische pinto, which is a combination of Japanese drawing and Punktscheckung. For clarity, it is assumed in the further discussion on the combination with monochrome ( g bzw.a ). The animals defined as standard typically are split, mating these animals with each other results in accordance with the Mendelian rules 25 % monochrome animals, 50 % and 25 % type Check Light Check. In theory it follows a mating of animals with monochromatic light check in 100 % type look. However, the factor for Punktscheckung with a so-called lethal factor (after Majaura better Semilethalfaktor ) linked, which means that light can check in have a significantly reduced viability. For reasons of animal welfare is therefore recommended to make preferred pairings between monochrome animals and type checking, in order to avoid the occurrence of homozygous Light Check. However, there is literary evidence that these Semilethalfaktoren that seem especially cause problems in the digestive tract, could be overcome by suitable diet for the individual animal and the breed by appropriate selection. The drawing of the type Check is essentially characterized by snout ( Butterfly), bakery items, fully colored ears, a dorsal stripe that runs up to the top of the flower and the side spots formed, which, as a band, as in the English pinto or as individual points can be constructed as in the giant pinto. As required in the breed standard Ideal drawings also be achieved in type piebald, not all animals. Schlohlaut indicates that the drawing of the Mecklenburg Pinto is due to the effect of point check factor.

Plate-or Gürtelscheckung

Plattenscheckung: German Symbol S for non- spotting, s1 ... 3 for different types of spotting, english You (from dutch dutch = ) for Nichtscheckung and dud ( dark) and duw (light ) for various Scheckungstypen. The mutants are not completely recessive to Nichtscheckung, the inheritance is not fully understood, according to Sandford several (even modifying ) genes are probably involved. The spotting is in the form of Dutch drawings in more or less standard contemporary expression of the Dutch rabbit ( in various combinations with the five Farballelen that leads to the large number of color strokes ) and in extreme expression in the Hototkaninchen in which the white spots except for the black eye circles cover the entire body of the animal. After Hochstrasser this factor should be called " Neuralleistendefektfaktor " on the background to the development of piebald spotting, see article. It should be noted that the numbering of the Plattenscheckungsfaktoren not correspond to single, accumulative genes but different mutation levels of the factor.

Leucism

Usually have rabbit (including albinos ) the factor for color formation X ( German symbol X, english symbol V). The English symbol refers to the White Rabbit Vienna ( Vienna White ) as the best known carrier of the mutated form of x and v, respectively, which leads to the non- formation of pigment, however, remain in contrast to the albino, colored eyes. Another representative of this mutation is the ermine rabbit in colors blue-eyed shock, so its the white fur of a completely different genetic makeup owes as the albino red-eyed ermine rabbit. Crosses between albino and leucistic rabbits produce a colored offspring because the offspring of the F1 generation from leucistic parent bring the dominant factor A / C and the albino parent factor X / V. The leucism is somewhat intermediate to the wild type, the offspring usually have white markings on the muzzle or legs.

The Plattenscheckung and leucism as parts of Neuralleistendefektreihe

Following Hochstrasser, there is no " Leuzismusfaktor " X / V in the rabbit but this factor is to be considered as a further mutation ( up to total loss of pigmentation ) of the Plattenscheckungsreihe. The gradation of these Neuralleistendefektreihe looks so like this:

• S - complete formation of the pigment
• Sa - sb sc sd ..... first sign of spotting in the form of single white hair, white tufts, forehead spot, etc.
• Si .... ideal training of the Dutch drawing
• Sn .... unknown mutation levels of the gene lead to severe spotting with complete predominance of white ( for example, when Hotot and Husum blue eye).
• Sx ..... complete loss of pigment as the White Vienna.
• Sxe ..... another mutation stage, moreover, leads to epilepsy in White Vienna next to the complete lack of pigment.

An interesting synthesis of Hochstrasser 's works are Majaura, which assigns the given modification factors quasi. In addition to the postulated Hochstrasser black amplifier series and the already longer known Yellow amplifier and Holländerscheckungsreihe this author is still a factor Z, whose mutations determine the strength and the expression of the Punktscheckung (of blanknasigen piebald, over the typical patching the point check breeds up to the jacket drawing).

As in other species, several different genes may be responsible for leucism and piebald, it is unlikely that it is mutations of the same gene in all these check patterns.

In addition, according to Castle lie the genes for leucism and Plattenscheckungen on different chromosomes.

The broadband - Factor

This, the width of the intermediate color -determining factor is in both symbol system denoted by W and the mutation ( wide -band) with w. For this reason, it is omitted here to the dual display of symbols. The wild-type W denotes the normal formation of the intermediate color, w leads to the broadening of the band, a corresponding author breed is not known. Sandford gives the German equivalent y1 .. 3 for the address given in the English system w mutant. According to the information provided by Rudolph / Kalinowski and Schlohlaut the Yellow amplifier in the English system is not listed.

Yellow amplifier (The Phäomelaninkontrollreihe )

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Enhanced expression of the yellow or red color in the rabbit fur is referred to in the German system with y1 .. 3, in the English system lacks this factor. The Dutch breed standard, which specifies the English and German Erbformeln to each race, the y- symbol at the corresponding breeds used in the English system. The unmutated type is denoted by Y. To find this factor is, in rabbits, rabbits and Deilenaar, it provides a rich chestnut brown coloration of the wild colored coat. Yellow Wild Coloured ( single color target time) breeds with additional amplifiers are yellow gold and Saxony Red New Zealanders. The Lohkaninchen give yellow amp the glowing tan. How could show Hochstrasser, the Yellow amplifier variations are dominant over the wild-type and must be marked with large letters. Partly this proposal is followed in the literature. The wild type is not marked with Y1, the mutation steps that will lead to enhanced expression of the yellow-red color with Y2, Y3, etc.. Since yellow amplifiers are usually listed only if they are relevant to the coloring of the respective rabbit, is hardly to be expected misunderstandings. In this article and the articles on the individual rabbit breeds in the conventional representation is followed. In contrast to the often -to-find representation, after which the yellow and red races should have seemingly different amounts of these yellow amplifier, Hochstrasser was able to prove that it is, that is, mutation levels of a gene is alleles, that is, to breeds with different yellow - or red color do not differ in the number of Gelbvertärker but in the mutation level of the gene. Are alleles of Phäomelaninkontrollreihe, i.e. the gene controls the storage of the dye into the hair of rabbit pheomelanin.

The eumelanin Control ( Black amplifier )

Hochstrasser explains the various forms of wild colored rabbit (in the form of color strokes Hell, rabbits and dark gray ) with the same after Nachtsheim hereditary formula ABCDG with the presence of a factor for control of the black pigment eumelanin, which in analogy to Phäomelaninreihe (Yellow amplifier ) as a black amplifier is referred to as a symbol for e proposed. Also here is the wild-type E1, the indicated opposite him dominant mutants as E2, E3, etc.. Hochstrasser explained by this factor, the color black amp blows iron gray and dark gray iron that. Than in the previous system mutants of the Black series (Bee and Be to Nachtsheim, Ed and Es according to the international classification) were considered Analogously, also in the form of recessive forms a black reduction (e1, e2, ..., etc.)

Red eyed dilution factor ( Lutino factor)

This mutation has occurred only recently (according Regitz 1985 in Denmark). Animals with this mutation show a fairly bright yellow wild colored coat, like a bright burgundy or the base color of yellow silver. The breeding in the Nordic countries takes place in the shades of color " shadow" ( cream- yellow body color with a bright blue bottom color and agouti badge bright blue) and " lutino " with yellow to orange body color and white to cream- colored belly and agouti markings. (quoted from Regitz ). Regitz are a symbol of the dilution factor in the rabbit u ( lu elsewhere? ) To (wild type then U and Lu? ). It is noteworthy that this mutant red eyes, anolog an albino shows, though not completely without pigment. The mutation could, in combination with the previously known Farballelen the breeding of new coat colors in the rabbit. Rudolph and Kalinowski 1982 cite a work of Fox (in Handbook of Genetics, 1975), and lead ( English ) Re icons for normal coloration and re for brightening and red-eye, but make no further information. In humans, this mutation corresponds to the Oculocutanem albinism type 2 and across species is referred to as pink -eye series. 1960 reported a 1949 first observed in Bremen mutation caused the red eyes without lightening the skin color and was symbolized with ra.

Hair structure

Long hair factor

The long-hair factor ( German V, v in the mutation, English L / L) occurs in the Angora rabbit and the fox (including dwarf forms ). While the hair while Angora is continually grows and shorn, subject to the long hair of the fox rabbit, which lacks even the angoratypische Ohrbehang, the normal shedding and does not need to be shorn. As used in the breeding out of the fox rabbit angora, the longhaired the fox rabbit will build on the long-hair factor attributed as the Angora, which is, however, also doubted by Schlohlaut.

Short coat ( Rexes )

Main article: Rexkaninchen

There are (at least) three loci known that in the rabbit Short coat ( Rex fur lead ). According to literature, these animals are phenotypically indistinguishable, but lead crossing each other in the F1 generation to normal -haired offspring. The day -to-find, at least in Germany, according Sandfort in the UK Rexkaninchen all belong to the Castor Rex - type ( or rex r1 ). However Joppich describes who has bred German Shorthair rabbits ( dek or r2) saying that differences with the French Rex so far existed when the German short hair was curled persianerartig all over. The animals of this line were also asked Nachtsheim available. The breed is apparently extinct already back in the thirties. Joppich mentioned in this context a Astrex or Astrachanrex with similarly crimped hair structure. Also this guy is apparently extinct. To which of the three types of short hair they belonged, or whether they represented a further mutation is not known. Sandford mentions this Astrex too, but also there as probably extinct. The Normannenrex ( nok or r3) had emerged in France as mutation breeding in large Russians rabbits. Although Joppich describes these animals in hair structure and health as the Castor Rexen and the German Short Hair for superior, even this breed is apparently extinct. A few years ago one designated as Astrex rabbit breed in Canada has emerged as to whether these animals is identical to the original Astrakhan Rexen is unknown.

Satin

Main article: Satin rabbits

The structured satin rabbit hair is a mutation of the normal factor ( Sa ) to (sa). The hair of the animals has a normal length, but a particularly soft, satin -like structure (name ), which also leads to a slightly different appearance of the coat color ( is white to ivory). The coat of the satin hair is about 3.5 cm long, the awns are fine and tower over the hair only slightly. The undercoat is very thin. The individual hair is covered by a thin, transparent with very fine flake or shingled surface pellicle. Due to the special structure of the hair coat colors in satin rabbits are particularly clearly visible.

More hair structures in the rabbit

Bart rabbit

Bart rabbits ( genetically identical with lion heads? ) Show a distinct beard or mane education, that is, the hair on the head and the bottom of the hull are significantly longer. Representatives of this type is the Belgian Bart rabbits.

Possum

In Sandford and Joppich the Opossumkaninchen is mentioned. Sandford describes it as Rexkaninchen, whose whole body is covered with ruffled, weißgespitzten hair that stick out at right angles from the body and give the animal a woolly appearance. The author also mentions that the Oposumcharakter is recessive to the "normal Rex". ( rex/r1? ). The mentioned at Joppich Opossumkaninchen is also a continuation of breeding rex rabbits, here German Shorthair ( dek / r2), further breeding seems not to be done. Following the development of the British Opossumkaninchens shown in Sandford, it is in this mutation is a combination of the short hair factors with the long hair factor.

The dwarf factor

The appearance of the known dwarf rabbits ( Hermelin and colors dwarfs ) with the stocky build and short close-set, taut upright ears is caused by the dwarf factor Dw (wild-type ) or dw in the mutation, showing an intermediate pattern of inheritance. The type dwarfs represent a spalterbigen genotype (Dw / dw ) represents the breeding of these animals with each other results in 25 % greater, not in accordance with the ermine rabbit in type rabbit with slightly longer ears ( " atypical, large color dwarf, Dw / Dw ), 50 % type dwarfs ( dw / dw ) and 25% homozygous animals of type ( dw / dw ), which are not viable, however, and at birth have a significantly lower weight. Some authors use the symbolism vice versa (wild-type dw / dwarfism Dw ). The dwarf factor is thus a homozygous lethal factor.

The cultured in addition to the colors Dwarf Dwarf Lop rabbits have not the dwarf factor in his mutated form.