GENETICS 101
Have you ever wished for more color in your Holland Lop nestbox? While the majority of competitive Holland Lops are torts or broken torts, adding some color to your lines can be fun and rewarding, and it can do much to alleviate boredom in your breeding program. There’s nothing more fun than finding a litter of different colors in the nestbox, except watching that “colored” Holland win on the tables. But before you go out and breed whatever color to whatever color, you should take some time to understand the basics of coat color genetics and how dominant and recessive genes work. There are a lot of unshowable colors in Hollands, and improper pairings of colors can lead to lots of beautiful, but ultimately unshowable rabbits, and poor choices can affect your herd for many generations. Understanding how genetic codes affect the way the rabbit looks can initially take some time to learn, but it is well worth the effort and will lead to less
frustration (and less feed costs in producing culls) in the long run. Understanding genetics will also help you get an understanding of how to use those typey torts with colors to move forward.
BASICS
The gene is the basic unit of inheritance. Offspring inherit one allele from each parent to make up the gene pair. Dominant alleles result in what you actually see on the rabbit. Recessive alleles are the ones that are hidden. In genetic code, dominant alleles are displayed with a capital letter and recessives are displayed with small letters.
A genotype is the genetic code of a rabbit. A phenotype is the way a rabbit looks. This is an important distinction, because rabbits are shown by phenotype, not genotype. For example, a smutty cream is sometimes shown as a Lynx. A self-chin is sometimes shown as a poorly colored black. However, just because a rabbit can be shown with poor color doesn’t mean that we shouldn’t strive for perfection. Knowing the rabbit’s actual genotype can help you make proper breeding and culling decisions that align with your color goals.
COAT COLOR GENOTYPES
The coat color genotypes for rabbits start with the first five letters of the alphabet. These are always shown in order of most dominant first. Remember that the most dominant gene is always displayed over a lesser dominant gene (meaning you will see the dominant gene). If the rabbit is displaying the most recessive gene, it cannot carry or hide a more dominant gene on the same locus (the same physical location on the chromosome). Rabbits that inherit two of the exact same allele from each parent (for example, if the rabbit inherits two agouti alleles, or AA) are homozygous for that gene. Rabbits that inherit a different allele from each parent (such as inheriting an agouti gene from one parent and a self gene from the other, or Aa) are
heterozygous for that gene.
PATTERN:
A – agouti: Banded fur; eye circles, nostrils, belly, inside of ears, and underside of tail are cream or white. Nape is colored.
at - tan: Similar pattern markings to agouti, but body is self-colored, not banded, and ticking only appears on chest, sides and lower hindquarters.
a – self: no coat pattern.
COLOR:
All rabbits are either black or chocolate.
B – black
b – chocolate
PIGMENT:
C – full color: full amount of eumelanin (black pigment) and phaeomelanin (yellow pigment) displayed.
cchd – chinchilla: the chinchilla gene leaves the black pigment and removes all or almost all of the yellow pigment, leaving a rabbit with black ticking.
cchl – sable or shaded: reduces the amount of black pigment and completely removes all yellow pigment. A rabbit that is homozygous for this gene will display very dark sable (seal) markings.
ch – Himalayan: reduces the amount of black pigment to the points and leaves no yellow pigment. Temperature sensitive (meaning points will darken in colder weather). Ruby eyes.
c – albino: removes all black and yellow pigment. A double dose of the albino gene will effectively mask every other coat color and pattern present, leaving you with a REW rabbit. Ruby eyes.
DENISITY OF COLOR:
D – dense, not dilute. Pigment granules are normally arranged.
d – dilute. Pigment granules are scattered.
EXTENSION OF COLOR:
Es – steel: almost full extension of black on the agouti hair shaft. This leaves almost all black with very little yellow ticking and covers the normally light agouti areas (belly, eye circles, etc...) with black. This is widely accepted to be the most dominant extension gene, but it is incompletely dominant, meaning that it must be paired correctly with other genes (notably the agouti and another full extension allele) to display its dominance.
E – normal extension: normal or wild type black
ej – Japanese (harlequin): black and yellow in patches or brindling
e – non-extension: black is not extended, leaving mostly yellow
*Please note that Ed and cchm will not be discussed as they are not yet widely agreed upon.
Because in most cases, recessive alleles cannot be seen behind dominant ones, you will often not know what recessive genes your rabbit carries unless you know how inheritance works or unless you test breed. In genetic notation, the line after a dominant allele indicates that the recessive allele is not known.
For example, in the genotype:
A_B_C_D_E_ (a chestnut rabbit), you can’t be certain what the second allele is without some further investigating or breeding. If this particular chestnut rabbit produces a blue tort when test bred, you will absolutely know that its notation is:
AaB_C_DdEe (that it carries self, dilute, and non-extension).
If your rabbit is already displaying the most recessive form of a gene, then it cannot be hiding something more dominant. For instance, if you are breeding for a sable point, you cannot look at a pedigree and state that a REW rabbit must carry sable because one of its parents was sable point. It simply doesn’t work that way. Let’s look at why:
A REW rabbit has the genotype ??cc??
REW rabbits (cc) cannot carry the sable (cchl) gene. It is on the same locus. If the sable gene were there, the rabbit would be not be a REW. REWs can not carry pointed, sable or chinchilla.
WOOL AND BROKEN GENES
If you are going crazy with fuzzies, this discussion may help you understand why you’re getting so many. After the pattern gene was introduced to Holland Lops, a wooled breed was brought in to improve fur texture that was lost, which introduced the recessive wool gene to the Holland gene pool. It is important to understand that the wool and pattern genes are chromosomally linked. This means that they reside very closely together on the chromosome strand and are usually inherited as linked sets. The outcome of this linkage is debatable (even Punnett and Castle, the researchers who are by and large responsible for most rabbit genetics known today, could not agree), but a slight increase in the probability was noted and accepted by both researchers. Many of you may be familiar with a Punnett square (a tool to determine probability of genetic outcomes). Here are the basic Punnett squares for probability for each gene:
Broken Gene:
EnEn—Charlie
Enen—broken
enen—solid
En en
En EnEn (charlie pattern) Enen (broken pattern)
en Enen (broken pattern) enen (solid pattern)
This Punnett square shows that two broken patterns bred together will yield 25% Charlies, 50% brokens, and 25% solids.
Wool Gene:
LL—normal fur
Ll—normal fur, but a wool carrier (may or may not have slightly longer fur)
ll—wool (Fuzzy Holland)
L l
L LL (normal fur) Ll (normal-furred wool carrier)
l Ll (normal-furred wool carrier) ll (wooled or fuzzy)
According to the basic Punnett square, two Hollands that both carry the recessive wool gene should produce 25% fuzzy Hollands. However, linkage may slightly skew these results. Because of linkage, the more you breed wool carriers, the more you may approach or even exceed a 25% probability for fuzzy Hollands in your herd.
Linkage explains why some Hollands produce more than their fair share of fuzzies, and why some breeders swear that the gene has different “strengths” of inheritance. You may have to resign yourself to having fuzzies in your barn if you linebreed for type. For those of you who currently do not have to fight the fuzzy gene, you may wish to be very careful in selecting stock to bring into your barn.
TIPS FOR BREEDING FOR SPECIFIC COLORS
If you feel you need some direction in choosing color partners and are wanting to avoid having to cull based solely on a rabbit having an unshowable color, you can use these notes to help you. Common potential problems are noted, except for breeding dilute to dilute (which will increase the likelihood of light nails). Genotypes are listed under each color for your reference.
SELF COLORS
Self colors are very versatile and are a good place to start adding color to your lines. There’s a saying that a good black rabbit is like a good black dress—it goes with everything. You will find the best type in the black-based self colors (torts are genetically self rabbits), and black and blue can easily be bred into tort, shaded, and otter lines without sacrificing quality. Black-based self can also easily be used in shaded
programs.
Black - aaB_C_D_E_
Breed to: Black, Blue, Tort, Blue Tort
Black to Black should produce the best nail color)
Agouti colors
Otter colors
Shaded colors
Chocolate colors
Don't breed to: Chinchilla can result in Self-Chin
Blue - aaB_C_ddE_
Breed to: Black, Blue, Tort, Blue Tort
Blue to a Black dilute carrier should help you produce rich, dark blues with darker nail color)
Agouti colors
Otter colors
Shaded colors
Chocolate colors
Don't breed to: Chinchilla can result in Self-Chin
Chocolate - aabbC_D_E_
Breed to: Chocolate, Lilac, Chocolate Tort, Lilac Tort, Chocolate-based Agouti or Otter colors
Can be bred to Black-based varieties, but Black is dominant and will mask Chocolate
Don't breed to: Shaded varieties should be avoided as chocolate shadeds are not recognized
Lilac - aabbC_ddE_
Breed to: Chocolate, Lilac, Chocolate Tort, Lilac Tort, Chocolate-based Agouti or Otter colors
Can be bred to Black-based varieties, but Black is dominant and will mask Lilac
Don't breed to: Sshaded varieties
Tort - aaB_C_D_ee
Breed to: Black, Blue, Tort, Blue Tort, Sable Point, Siamese Sable, Smoke Pearl, Agouti colors
Don't breed to: Chinchilla can result in Self-Chin
Otter can result in Tort-Otter
Blue Tort - aaB_C_ddee
Breed to: Black, Blue, Tort, Blue Tort, Siamese Sable, Smoke Pearl, Agouti colors
Don't breed to: Chinchilla can result in Self-Chin
Otter can result in Tort-Otter
Sable Point can result in Blue Point
Chocolate Tort - aabbC_D_ee
Breed to: Chocolate Tort, Lilac Tort, Chocolate, Lilac
Can be bred to Black-based varieties, but Black is dominant and will mask Chocolate
Don't breed to: Chinchilla can result in Self-Chin
Otter can result in Tort-Otter
SHADED VARIETIES
Lilac Tort - aabbC_ddee
Breed to: Chocolate Tort, Lilac Tort, Chocolate, Lilac
Can be bred to Black-based varieties, but Black is dominant and will mask Lilac
Don't breed to: Chinchilla can result in Self-Chin
Otter can result in Tort-Otter
Shaded varieties
SHADED/SABLE COLORS
You might notice that the ARBA Standard of Perfection lists torts as shaded varieties. They are in the sense that they have shaded markings. However, many people use the term “shaded” to reference those rabbits that display the sable gene. Having a shaded program implies that you are breeding for the sable colors. The sable colors—Siamese sable, sable point, seal, and smoke pearl—can easily be bred into tort lines. Although they will be recessive to a tort’s full color gene, you can get them to pop up in litters if both parents carry shaded, pointed or REW.
REW and pointed are not genetically shaded rabbits (can’t be), but it is often necessary to use them in a shaded program since a rabbit that has two sable genes will be a seal, seal point, or dark smoke. To produce correctly colored sables, the second allele should be recessive to the sable gene, meaning it should be pointed (ch) or albino (c). Please note that using REW with your sables will not necessarily clean up smut; it just results in the correct pairing of genes to produce a sable. Modifiers can be responsible for smut, as can using the chinchilla gene. A chinchilla rabbit with self and non-extension genes (a sallander or iron grey) rabbit (aaB_cchd_D_ee) can phenotypically look like a sable point. I have seen these in Hollands, and they
can be strikingly beautiful. They can range from light pearl to a very smutty pearl, though are typically darker or smuttier and lack the slight reddish glow in the iris of a true sable point. For those breeding to the standard, you will want to make sure that the sable points in your program aren’t genetically sallanders. While some breeds (most notably the Satin) actually prefer to use the chinchilla based color in order to get consistent litters of the same color without having to deal with the effects of a double sable gene (which results in a seal), if you have the chinchilla gene in your sable program, you might not ever be able to clean up smut. How will you know if you have the chinchilla gene? First, look at the pedigree. Is there chinchilla
in the background? This could be one indication (though not always a reliable one). You could breed the rabbit in question to a REW known to have the genotype (aaB_cc_D_E_). If you get what looks like black (or even blue), you will know that the rabbit is chinchilla based, and the resulting black or blue is actually a self-chin (you will know this because a sable or sallander bred to a REW cannot genetically produce a full-color rabbit). In addition, if you get marbled or blue-grey eyes on your sable points or Siamese sables, they are most likely chinchilla based.
Siamese Sable - aaB_cchl_D_E_
Breed to: Siamese Sable, Sable Point, Smoke Pearl, Pointed, self REW, Black, Blue, Tort,
Don't breed to: Agouti can result in Sable Agouti
Otter can result in Sable Marten
Sable Point - aaB_cchl_D_ee
Breed to: Siamese Sable, Sable Point, Smoke Pearl, Pointed, self REW, Black, Tort
Don't breed to: Agouti can result in Sable Agouti
Blue Tort can result in Blue Point
Otter can result in Sable Marten
Seal - aaB_cchlcchlD_E_
Breeding to REW will result in 100% sables
Breed to: Siamese Sable, Sable Point, Smoke Pearl, Black, Blue, Tort, Blue Tort
Don't breed to: Agouti can result in Sable Agouti
Otter can result in Sable Marten
Smoke Pearl - aaB_cchl_ddE_
Breed to: Siamese Sable, Sable Point, Smoke Pearl, Pointed, self REW, Black, Blue, Tort
Don't breed to: Agouti can result in Sable Agouti
Otter can result in Sable Marten
REW - ??cc??
Breed to: Siamese Sable, Sable Point, Smoke Pearl, Pointed, REW, Black, Blue, Tort, Blue Tort Depend on genotype—please review lineage before breeding REWs into your lines. A REW out of agouti or chocolate lines can mess up your shaded program
POINTED COLORS
If you are breeding for pointed Hollands, please note that a pointed (ch) crossed with a REW (resulting in chc) will produce pointeds with abbreviated points. A pointed that is homozygous (chch) produces the most brilliant color on points and a larger nose marking, which is desirable.
Pointed Genotypes
aaB_ch_D_E_ (Black)
aaB_ch_ddE_(Blue)
aabbch_D_E_(Chocolate)
aabbch_ddE_(Lilac)
For best point color, breed Pointed to Pointed only.
Siamese Sable, Smoke Pearl, Black, Blue (though these are higher in dominance)
Self-REW
Agouti
Non-extension colors (ee) can result in torted points, which will lack proper color Otter
Pointeds should not be bred to broken pattern, as they will lack boot color (a DQ)
OTTER COLORS
If you are looking to improve type on otters, it would be best done with a good black rabbit. However, many breeders introduce red or orange to their otter program to increase the rufus in the offspring. This is a several generation fix, as agouti is dominant to otter. It also introduces the non-extension gene, which can create future problems. It is best to avoid torts, since you will have to cull tort otters.
Otter Genotypes
at_B_C_D_E_ (Black Otter)
at_B_C_ddE_ (Blue Otter)
at_bbC_D_E_ (Chocolate Otter)
at_bbC_ddE_ (Lilac Otter)
For best color, breed Otter to Otter
Acceptable: Black, Blue, Chocolate, Lilac
Don't breed: Non-extension (ee) colors can result in Tort Otter
Chinchilla can result in Silver Marten
Sable can result in Sable Marten
AGOUTI COLORS
The agouti colors are dominant to the self colors. While agoutis can be used with most self colors, it is best to avoid mixing your agouti and shaded programs, as this will create sable agoutis (also often called sable chins). Chinchilla should also not be used with self rabbits if you can help it. The most brilliant chinchilla color will be produced by breeding chin to chin. Please note that if your chinchilla rabbits are homozygous for the chin gene, they can have blue-grey eyes (eye color in chinchillas can be problematic due to linkage).
Chestnut - A_B_C_D_E_
Best to breed to: Other Agouti patterns, Steels
Acceptable: Black, Blue, Tort, Blue Tort
Don't breed to: Sable can result in Sable Agouti, a non-showable color
Opal - A_B_C_ddE_
Breed to: Other Agouti patterns, Steels
Acceptable: Black, Blue, Tort, Blue Tort
Don't breed to: Sable can result in Sable Agouti
Chinchilla - A_B_cchd_D_E_
Breed to: Chinchilla, Squirrel
Other Agouti patterns, Steels
Don't breed to: Self can result in Self-Chin
Sable can result in Sable Agouti
Otter can result in Silver Marten
Squirrel - A_B_cchd_ddE_
Breed to: Chinchilla, Squirrel
Other Agouti patterns, Steels
Don't breed to: Self can result in Self-Chin
Sable can result in Sable Agouti
Otter can result in Silver Marten
Chocolate Agouti - A_bbC_D_E_
(also known as Chocolate Chestnut)
Breed to: Chocolate Agouti, Chocolate Chinchilla, Lynx, Chocolate-based Frosty, Chocolate, Lilac
Can be bred to black-based varieties, but black will mask chocolate.
Don't breed to: Sable can result in Sable Agouti
Chocolate Chinchilla - A_bbcchd_D_E_
Breed to: Chocolate Chinchilla, Lynx, Chocolate-based Frosty
Chocolate Chestnut,
True Lynx
Black-based Agouti colors (black will mask chocolate)
Don't breed to: Self can result in Self-Chin
Sable can result in Sable Agouti
Lynx - A_bbC_ddE_
Bred to: Lynx, Chocolate Agouti
Chocolate Chinchilla
Black-based Agouti colors (black will mask chocolate)
Don't breed to: Sable can result in Sable Agouti
*As a side note, true lynx is a chocolate-based color. Most “lynx” Holland Lops are actually smutty creams. Rabbits are shown by phenotype, not genotype, so this is a hard call. However, for the sake of honesty in breeding practices, selling a smutty cream as a lynx should be avoided since the genotypes are completely different. If there is no chocolate in the pedigree, chances are very high that it is not a lynx. Also, if both parents are non-extension (ee), the rabbit cannot genetically be a lynx.
STEEL COLORS
There is much confusion regarding the steel gene. This is because it is an incompletely dominant gene. It must be paired with at least one agouti gene and the extension gene (E) to correctly display. The proper pairing of alleles on a steel colored rabbit would be EsE. Some people state that Ese will produce steels (and it may produce very poorly colored ones), but steel should be paired with one allele of the normal extension gene (E) so that the color will extend nearly the full length of the hair shaft. Two steel alleles (EsEs) will produce a rabbit that looks nearly black. These are called super-steels. The agouti gene also affects steel coloring. A rabbit with self coloring will appear black—you must have the agouti gene to get a
properly colored steel. Care should be taken to avoid using true self-colored rabbits (non-agouti based) in a steel breeding program. Because steel must be paired with agouti to correctly display, if you keep using self-colored rabbits in the program, you will not know which of your rabbits carries steel and you can end up with some strange surprises down the road. I believe most “exceptions” to genetics rules (such as getting agouti rabbits out of two “self ” rabbits) result from hidden steel genes.
Steel (Ticked) Genotypes
A_B_C_D_EsE (Black Gold Tipped)
A_B_cchd_D_EsE (Black Silver Tipped)
A_B_C_ddEsE (Blue Gold Tipped)
A_B_cchd_ddEsE (Blue Silver Tipped)
A_bbC_D_EsE (Chocolate Gold Tipped)
A_bbcchd_D_EsE (Chocolate Silver Tipped)
A_bbC_ddEsE (Lilac Gold Tipped)
A_bbcchd_ddEsE (Lilac Silver Tipped)
Best to cross with: Agouti varieties
Don't cross with: Self (results in self-steel)
Non-extension varieties (Tort, Orange, Cream, etc…)
To produce a properly colored steel, most breeders will breed steel to agouti. You can breed steel to steel, but 25% of the litter will be super-steels (EsEs). These will look like a self rabbit, and sometimes the only way to tell them apart is at birth (they are born with light bellies that turn dark later) or by test-breeding. A supersteel is useful in a steel breeding program as it will consistently produce steel when paired with a chestnut, opal, or chinchilla that is homozygous for the agouti gene. Here is a chart that may be helpful in determining what would happen if you bred the different steel gene combinations to self, otter, or agouti rabbits:
aa (self ) at (otter) A_ (agouti)
EsEs Black * Black * Steel
(* may have ticked guard hair on the blacks)
EsE Black Black Steel
Esej Black Black Black
Ese Black Black Black
*Roush, Stephen. 2011. Advanced Genetics. RabbitCon. Indianapolis.
“WIDEBAND” COLORS
Although the groupings in the ARBA Standard of Perfection reference a wideband group, Hollands in this category do not technically have the wideband gene (except for possibly red). Truthfully, what they have in common is that they are agouti (A) and non-extension (ee). The wideband gene allows deeper colors to be more visible.
If an animal truly has the wideband gene, it will cover all belly undercolor. This would be a DQ for anything other than red. You can see the wideband gene at work in other breeds, most notably the Tan. If your reds are truly genetically wideband, be careful about using them with other colors.
Rufus modifiers play a large part in developing good color on reds and oranges. These affect depth of color by intensifying the yellow pigment. Because all rabbits have yellow in the hair shaft (except when removed by other genes), rufus modifiers will affect the brilliance of all colors, not just red and orange. Think of a Madagascar tort—these are thought to have high levels of rufus modifiers. There are 6 levels of rufus modifiers, with R6 being the highest. While the results of increasing rufus are easiest to see on the oranges and reds, if you want to increase depth of color on your rabbits, pair them with rabbits with high rufus factor. Black and blue rabbits with high rufus factor are incredibly brilliant.
Red - A_B_C_D_ee (high rufus)
Best to cross with: Red
Orange, Fawn, Cream - Low Rufus colors
Don't cross with: Sable can result in Sable Agouti
Orange, Fawn - A_B_C_D_ee
Best to cross with: Orange, Fawn, or Red, depending on your desired level of Rufus
Agouti colors
Tort, Blue Tort
Don't breed to: Sable can result in Sable Agouti
Cream - A_B_C_ddee
Best to cross with: Orange, Fawn
Agouti colors
Tort, Blue Tort
Don't cross with: Sable can result in Sable Agouti
Frosty - A_B_cchd_D_ee
A_B_cchd_ddee
A_bbcchd_D_ee
A_bbcchd_ddee
Breed to: Chinchilla, Frosty
Agouti colors
Don't breed to: Self can result in Self-Chin
Sable can result in Sable Agouti
TRI-COLORS
Tri-colors are the result of breeding a harlequin to a broken pattern. Most Holland breeders will use oranges in a tri-color program since these are readily available and can often be found with good type. Fawns and creams are also good choices to pair with a harlequin. However if you are aiming for brilliant color, your tri’s
should actually carry two copies of the brindling gene (ejej). This is something that may take several generations to accomplish, but you will be able to if you keep the resulting tri’s or harlies and breed them together. An orange paired with a harlequin will result in the rabbit carrying (eje), which often do not have the brilliant coloring of the (ejej) rabbit. Tort could be used to bring in type, but you should be aware
that a self-colored harlequin results in a torted tri, which has very poor color. And in the end, you will still have to bring the agouti gene back in to get proper color. The best option would be to use the best orange you could find and avoid using the torts if possible. In fact, you should avoid using self colors altogether. You should also avoid breeding to any rabbit that carries a more dominant gene, such as E or Es. Therefore, you need to avoid steels, chestnuts, opals, blacks, blues, etc. The ideal scenario to get properly colored tri’s is to breed a solid harlequin to a charlie harlequin, which will result in 100% broken. The brindling gene should NOT be bred into your herd without proper thought and without the specific goal of breeding for tri’s, as even one copy of the recessive gene (Eej) can produce rabbits with brindled patches. If you introduce the chinchilla gene to your tri program, you will get magpies, but these are not showable.
TRICOLOR
A_B_C_D_ej_Enen (Orange/Black)
A_B_C_ddej_Enen (Fawn/Blue)
A_bbC_D_ej_Enen (Orange/Choc)
A_bbC_ddej_Enen (Fawn/Lilac)
Breed to: Tri-colors, Harlequins
Orange, Fawn, Cream
Don't breed to: Any other color
BLUE-EYED WHITES
Blue-Eyed White rabbits are the result of the Vienna gene. BEW will mask all other colors and patterns.
VV—non-Vienna marked (no effect on color or pattern)
Vv—Vienna marked (white markings)
vv—Vienna (white with blue eyes)
All rabbits have this loci. However, only those with at least one copy of the recessive gene will display Vienna markings. A rabbit that is homozygous for the recessive gene (vv) will be a blue-eyed white. It is important for breeders to fully understand how BEW might affect their herd for many, many generations to come, since it only requires one copy of a recessive gene to cause mismarks. At the same time, it is possible to have offspring that carry the Vienna gene that do not display white spots or BEW markings, meaning that the gene can hide for many generations. Breeding the Vienna gene into your herd should not be done haphazardly.
BEW - ?????vv
Breed to: BEW
Vienna marked
Don't breed to: Chinchilla, Sable, Pointed, Chocolate varieties, REW (all create eye-color issues)
CONCLUSION
I hope the information provided proves useful to you in your breeding program. Just remember that color is a bonus and type should always come first. We don’t want to lose all of the tremendous gains that have been made in type over the years. Color can be changed in one or two generations for the most part. Poorly
typed animals take years to improve. While adding color can be fun, it doesn’t do any good to create generations of culls. Just because our judging standard doesn’t allocate many points to color doesn’t mean we shouldn’t continually be trying to improve the breed overall. It might take some patience to get the whole package of type and color, but your patience and work will be rewarded when that special “colored” Holland Lop wins on the tables!
REFERENCES
The Genetic Structure of Domestic Rabbits Evolution. Available at: http://eebweb.arizona.edu/nachman/pdfs/Carneiro_et_al_2011.pdf
The Genetics of Domestic Rabbits. Castle, W.E. 1930. Cambridge Harvard University Press.
Linkage of Dutch, English and Angora in Rabbits. Castle, W.E. 1924. Proceedings of the National Academy of Sciences, 10(3): 107-108. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1085547/pdf/pnas01864-0025.pdf
A Note on the Inheritance of the “Steel” Coat-Colour in Rabbits. Onslow, H. 1922. Journal of Genetics, 12(1): 91-99. Available at: http://www.ias.ac.in/jarch/jgenet/12/JG_12_92.pdf
On the Series of Allelomorphs Connected with the Production of Black Pigment in Rabbits. Punnett, R. 1930. Journal of Genetics, 23(2): 265-274. Available at: http://www.ias.ac.in/jarch/jgenet/23/265.pdf
Further Experiments on the Inheritance of Coat-Colour in Rabbits. Punnett, R. 1915. Journal of Genetics, 5(1): 37-50. Available at: http://www.ias.ac.in/jarch/jgenet/5/JG_5_37.pdf
Inheritance of Coat Color in Rabbits. Punnett, R. 1912. Journal of Genetics, 2(3): 221-236, Available at: http://www.ias.ac.in/jarch/jgenet/2/221.pdf
Genetic Studies of the Rabbit. Bibliographia Genetica. Robinson, Roy. 1958. 17,3: 228-558. Available at: http://lit.rabbitcolors.info/robinson.html