Roseclover Homestead Turkeys

Genetics Basic Overview

The field of genetics as we know them today began in the 1800's, but even without a name or full understanding for it, selective breeding had been occuring well before this. In turkeys, there are no current accurate DNA tests for color, but the science predates the discovery of DNA and is quite reliable. Unfortunately, it does take a little more work than sending a blood sample off to a lab and having them tell you the result. In simplest terms, color genetics is looking at the color genes from the sire (dad) and the color genes from the dame (mom), and using this informatiion to determine what color we will see in the offspring (children). Turkey color genetics can seem complicated because several genes work together to create the final appearance of the bird.

Gene: The A unit of inheritance for hereditary traits

Allele: A specific version of a gene.

Chromosome:The actual structural that contains genetic informaton. Each chromosome will contain thousands of loci (next definition) and since under normal circumstances the chromosomes are always in pairs, the loci are always pairs as well

Locus: The "spot" in the chromosome where the gene "lives" and where those specific alleles can be found. They are alwasys in pairs because the chromosomes they are on are in pairs. There is one exception explained further along. Plural of locus is loci.

Genotype: The way to write out the different alleles at each loci so that the color can be interpreted

Phenotype: The way the colors express (look) from the genotype

Dominant:The allele that will express most when in a heterozygous(split) pair of genes.

Recessive: The allele that will express less or not at all when in a heterozygous (split) pair of genes.

This isn't algebra. You're not trying to find the value of "x" in the equation. The letters are more like state abbreviations in the US for mailing. They are about as close to just being initials as they could be without being confuseable with any other abbreviation.

Now, a basic concept of inheritence is that offspring (children) get half their genetic material from one parents and half from the other. If that is confusing, picture the parents instead as two glasses of water. The water is their genetic material. Their child is a new, equally sized glass that can only hold the same amount of genetic material. To fill the glass perfectly, each parent pours just half of their material into the new glass. The metaphor doesn't work perfectly, because the parents will still be "full" but in terms of visualization, this is meant to show that half of the offspring's chromosomes are from mom and half are from dad. So, all the chromosomes are in pairs, which means all the loci are in pairs which means all the letters (abbreviations for the alleles) will be written in pairs. For example, lowercase "b" is the abbreviation for "bronze." However, if a bird is standard bronze, there will be two copies of that gene, so it is written as "bb."

If you are familar with mammals or heard some political speak we won't get into here, you're familiar with hearing about X and Y chromosomes. Again, chromosomes under typical circumstances are always in pairs, and for mammals, two X chromsomes (XX) cause genetically coded females and an X with a Y (XY) cause genetically coded males. In birds, it is flipped and there are different sex chromosomes. Two Z chromosomes (ZZ) is male and a Z with a W chromsome (ZW) is female.

Now, to back up for a second and show why this matters, think of each chromosomes and each locus on that chromosome as a set of instructions. Instruction sets come in two pages with each locus on each chromosome being read by the assemblers to give the final results. In terms of female birds, if there is a mutation on the Z chromosome, the assemblers only have one half of the instructions, the other page isn't there. Instead, there is a W chromosome. In terms of color genetics, there are two color mutations that occur on the Z chromosomes that will be explained below. For these color genes, females only need one copy that they will inherit from dad with his Z chromosome because mom gives them the a W chromosome. Essentially, the assembly just proceeds with the instructions that are there and since there is only one set of instructions on the one Z chromosome for females, those are the instructions that are followed with.

Mutations... That's the short answer. In terms of turkeys, the bronze is considered the standard. All wild types of the meleagris gallapavo (read the history section for more on this) are considered bronze. It is the default setting for turkeys if you will... In terms of writing out the genotype, there is a long version and a short version. The short version assumes that for any locus (pair of allele abbreviations) not written out, there are no other mutations present and everything is in the factory default setting.

Therefore bronze can be written in shorthand as bb. But the full genotype would be written out as this:

You start with bb at the first locus, and then each space separates one locus from the next. It is important to know what the default settings are so you know when to change something and write out the full genotype. Otherwise, it would be best practice to just write it out fully each time as you're learning it.

I have heard this thinking before... "Dominant genes are the default ones, right?" No... again, bronze is considered the standard with no mutations, but it is written as two lowercase letters: bb. Black is a dominant mutation that occured at this same locus and is therefore written as capital B. It is important to understand it is at the same locus and not a separate place. Black is only dominant over the other alleles at this locus. It is another bad assumption to assume dominant means dominant over all the other loci. It is just for the locus where it is found.

So, since black (B) is dominant, in a heterozygous (split) pair, such as Black (B) and bronze (b) i.e. Bb, black will be the predominant color. I say predominant, because the next part is a little confusing... There is what is known as incomplete dominance/incomplete recessiveness. What this means for a split Bb color is that while the bird is mostly black, there is enough of the bronze gene poking through that it is not fully black. Therefore, a turkey with the genotype BB is just black and one with the genotype Bb is Barred Black because the barring shows through.

The genotype is what we have been writing out with all of the different gene (letter) combinations. The phenotype is what the bird looks like. This is important to remember. The phenotype gets the name. They were naming phenotypes before they ever knew what the genotype was or could be. For a simple example, we have to look at the next locus over from the bronze.

CC is what is written in the default above, and all this means is normal color. C is the dominant allele. There are a total of four alleles at this locus, one being white which is written as a lowercase c meaning it is recessive. It is essentially, "no color," as when there are two copies (cc) it blocks all pigment from showing in the feathering.

Cc would be split for both normal color (C) and white (c). However, in this case, the white would be fully recessive. There is no indication that it is there in the visible expression (phenotype). So, a turkey with the genotype bb Cc would just be bronze. If you ever see/hear anyone say that a turkey looks/is half bronze, half white, that's your sign that they don't know what they are talking about. There will be zero indication that this turkey carries the white allele. It will just show "C" or "normal color."

The first two loci are probably the most confusing of the bunch because there are three aleles at the bronze locus (B, b, and b1) and four allele at the color locus (C, cg, cm, and c). Just remember, only two can be present at one time. Your turkey will not be Bbb1 or bb Ccgcmc. There will only be two, no matter what combinaton there is.

The rest are easier with only two alleles at each locus (spot). In these ones loci, you can treat them as basically a yes or no question. One of the alleles is yes and one of the alles is no. So in the default example above, all of the other loci after CC are the "no" answer. So, skip over bb CC... dd EE NN PnPn RR SlSl are all in the "no" setting. See a further breakdown of each allele below!

Very large genetics overview image — replace underconstruction.jpg with your custom image

Add additional Genetics Basic Overview text here. This paragraph is intentionally placed below the large image so you can continue the lesson after the visual.

Turkey Color Genes

What it all means

Essentially, a helpful way to picture it is like a vending machine. Each locus is a row. If you are trying to get a chocolate bar that is in row A, spot 2, you would put in your cash and click A2. Well for turkey color genetics, the rows are the loci. You have row b, row c, row d, row e, row n, row pn, row r, and finally, row sl. They are in alphabetical order, but obviously things differentiate fromt he alphabet after row e. Now, where it differs is instead of numbers, you are selecting a pair of letters to spit out the final product. For example, if you're in "row d," you then would be selecting either DD, Dd, or dd as your 1, 2, or 3 options. For your own purposes, if you like numbers more, you could write things out this way... But for I am more of a letters person and happy to stick with the conventional, accepted way.

Now, instead of just getting a singular candy bar, picture instead that this vending machine is full of ingredients needed for a pie. Scrolling through the list of varieties is a lot like scrolling through types of pie. What variety you get is like asking what kind of pie you have... it depends what went into it. Did you put six types of fruit in there, or is it just apple? All depends what was dialed up in the hypothetical vending machine.

Now, unfortunately, as a breeder, you don't have full control of this. Turkeys will pass on only the genes that they have and in whatever way they happen to pass them on... For a heterozygous (split) pair of genes, the odds as to which gene get passed on to the offspring are technically 50/50, but that's not always how it goes.

Locus 1 — The Bronze Site aka Base Color

b • B • b1

b = bronze

B = Black

b1 = black-winged bronze

This is the Bronze Site, but refered to frequently as the Base as well. In short form genotype, this is the only one that is essentially to write out as a bird must have a base color even if the rest are defaults. Now, in terms of dominance, there is a hierarchy. Black is the most dominant followed by bronze and followed lastly by black-winged bronze. Again, only a pair of alleles can be together at once. The possible combinations are only BB, Bb, Bb1, bb, bb1, and b1b1.

As far as combination, for the homozygous (non-split) pairs, BB is black, bb is bronze, b1b1 is black-winged bronze. Now, here is where phenotype comes into play in terms of naming the color variety. Bb and Bb1 are both Barred Black. They have two different Genotypes, but phenotypically appear the same. Similarly, bb1 is considered just bronze. It is incomplete dominance, so you can see signs of the split genotype, but the overall phenotype remains bronze.

Locus 2 — Color

C • cg • cm • c

C = Normal Color

cg = gray

cm = mottling

c = white (no color)

This is probably the most complicate locus because there are four alleles and multiple interactions. For the homozygous pairs, CC is the default of normal color. Because it is the normal/default, for the short form genotype, CC is not written out. Contrarily, cc needs to be written because it produces white which is significant. White hides essentially everything else as it just blocks pigment from showing. There can be leakage occassionally, but typically every feather will lack pigment and be white. Again, C and c together (Cc) shows only normal coloring.

cgcg is homozygous gray, but don't be confused. It does not automatically turn the whole bird gray. The different loci interact in ways. The genotypes BB cgcg and bb cgcg do not show anything. But b1b1 cgcg changes the phenotype from a black-winged bronze to a sweetgrass. In fact, b1b1 Ccg changes the phenotype from black-winged bronze to that of a Cornish Palm.

Conversely, while cm is mottling and cmcm created mottled variants, Ccm and cgcm are not affected. Ccm is normal coloring and cgcm is essentally just gray. But mottling (cm) and white (c) do interact. The cmc combination creates painted varieties and fawn varieties: BB cmc is painted, bb cmc is fawn, and b1b1 cmc are white-winged fawn.

If you've been keeping track, the last combination is gray (cg) and white (c). This is probably the one mentioned the most, but occuring the least... cgc.

BB cgc and bb cgc do not show anything as is. But b1b1 cgc is the "legendary" light sweetgrass. I am trying to stay informative, but I would be remiss if I did not address this elephant in the room. Sweetgrass are a popular variety, but I wish they weren't because I hate this one factor about them... The phenotype varies... They can be very dark and saturated or very light with far less coloration and still be the same genotype: b1b1 cgcg. Nonetheless, it is often assumed that the lighter colored sweetgrass are b1b1 cgc aka "Light Sweetgrass." They might be... but probably not. Again, there's no DNA test, so the way to prove it would be through breeding. Two light sweetgrass would produce some white offspring.

Locus 3 — Dominant Slate

d • D

d = recessive allele = "no" dominant slate"

D = Dominant Allele = Dominant Slate

This is where you have to understand the difference between a phenotype/variety name vs a gene/allele name. Dominant Slate is the gene that causes the variety we (in the USA) typically think of as slate, or blue slate, but only in a specific combination. BB Dd is the shortform genotype for a blue slate. This gene does not turn any other variety into blue slate. For example, b1b1 cgcg is a sweetgrass. Adding dominant slate (D) does not change the variety to a blue slate. It does, however, show through and change the phenotype/variety to Blue Sweetgrass.

Rewinding, BB Dd is a blue slate. This is a heterozygous gene pair. BB dd is just black as there are no copies of the slate gene. BB DD is known as a Lavender with two copies of the Dominant Slate gene. Two copies of Dominant Slate together typically produce a lighter color than one copy align as they dilute the pigment further. A clear visible difference between a BB Dd and BB DD is that the Lavender will have diluted all of the black pigment where as in a BB Dd blue slate, there will always be flecks of black showing through in the feathers.

Now, keep in mind, there is a reason Lavender varieties are not kept much. The slate variety was nearly excting within the United States apart from a few remaining flocks. Those remaining slates created a very narrow gene pool from which all other slates had been bred. Unfortunately, two copies of Dominant Slate together are associated frequently with a lethal neurological problem. It is not always the case, but it is frequent enough that is needs to be considered when breeding together varieties that carry the gene. For true breeding slate varieties, read about recessive slate (sl) below.

Locus 4 — Extended Bronze aka Brown (Sex-Linked Color)

E • e

E = "No" for extended bronze

e = extended bronze

E is the normal coloration and is the dominant allele. The name extended bronze is why the abbreviation is "e," but there really wasn't a better way to abbreviate it either... It is "extended bronze" because the brown/bronze color replaces all of the black pigment. Keep that in mind because a turkey cannot have any black pigment if it is expressing the extended bronze gene. So a black turkey (BB) with this gene would be written as BB ee for a male. The black is gone. It is now just showing the brown and is known as the chocolate variety.

Now, back to the name, this gene is typically referred to as brown, but there really was not a better way to abbreviate than to stick with the "e" for extended bronze. "b" was already taken with the bronze allele. "r" is taken by "red," and "n" is Narragansett. "o" and "w" were technically available, but this is just as confusing as sticking with "e."

The sex-linked part... Start with it being linked to the Z chromosome which, again, ZZ is a male and ZW is a female turkey. Therefore, males can be written as EE, Ee, and ee, but for a female, there are only two options: E- or e-. The "-" is just another way of saying "Nothing." And "Nothing" just means, follow the only set of instructions that you have. So with one set of instructions inherited from dad, this will be the color the female offspring express. And because they do not have a second gene (cannot be split), there is only the two options. Is it yes or no? Brown (e) or normal (E)?

Toms have two genes though and can be split in alleles. Their yes is ee, their no is both EE and Ee. This is why it is possible to have sex linked offspring.

Locus 5 — Narragansett (Sex-Linked)

N • n

N = "No," not Narragansett.

n = Narragansett.

Narragansett, similar to slate, is a variety, but also a gene. A bronze base (bb) with Narragansett (nn for males, n- for females) makes a Narragansett variety. But the gene is part of many other varieties as well. A common one, Royal Palm, is a sweetgrass with the Narragansett gene: b1b1 cgcg nn/n-.

Narragansett is a dilution gene that dilutes the pigment. This is why some varieties with the Narragansett gene just get "Dilute" added to their name. For example, a Rusty Black is BB Rr, but add Narragansett, and it is a Dilute Rusty Slate at BB nn/n- Rr.

Again, like the brown gene before it, it is sex linked. Males can be NN, Nn, or nn. Females can only be N- or n-.

Locus 6 — Penciling

Pn • pn

Pn = Dominant Allele = Not Penciled

pn = recessive allele = penciled

There are rules to this one... There are no penciled black or penciled bronze varieties. Penciling is only present in varieties of black-winged bronze. It is incomplete recessive and typically shows in birds that are b1b1 Pnpn, but is much more prominent in b1b1 pnpn varieties. Penciling causes jagged, vertical lines most prominent in the wing and tail feathers. These lines look a bit like someone scribbled with a pencil from top to bottom of the feather.

Vermiculation is often confused with penciling. Vermiculaton is typical in many varieties and is not associated with a particular, identified locus. Vermiculation cause the horizontal lines that go across the feather and often trace the inner outline of the feather. The Red Bronze variety is probably one of the best example of vermiculation, and again, while confused with penciling, it is not the same thing and the patterns are unrelated.

Locus 7 — Red

R • r

R = Dominant Alelle = "No" Red

r = recessive allele = red.

Red is another incomplete recessive allele. The phenotypical changes due to the homozygous combination of R and r (Rr) often leads to the naming of entirely new varieties, some conventional, and some unconventional. Rr in dark varieties leads to the "Frosted" name and genotype. In black varieties, "Rusty" is typically used. In black-winged bronze varieties, the pattern is all new names.

b1b1 = black-winged bronze and b1b1 Rr = Harvest Gold.

b1b1 cgcg = Sweetgrass and b1b1 cgcg Rr = Fall Fire

The pattern continues with varieties such as Calico and Red Phoenix.

So what makes it recessive if it shows through? Well, two copies of red make varieties like Bourbon Red (bb rr) and Jersey Buff (BB rr). One copy of red leaves mostly the standard phenotypes with red influence. Two copies of red, for the most part, take over.

One last thing to keep in mind, remember, just because an allele is dominant at it's locus does not mean it dominates all loci. Slate (D) is a dominant allele, and when combined with one copy of red (r), it remains mostly dominant... But don't assume that means double dominant slate (DD) would be predominant over double recessive red (rr). In a bird like this, the slate gene is barely visible apart from the edging on the featehrs.

Locus 8 — Recessive Slate

Sl • sl

Sl = Dominant Allele = "No" Recessive Slate

sl = recessive allele = recessive slate.

Recessive slate is a true breeding color as it takes two copies to display. It is fully recessive, and one copy (i.e. Slsl) does not show in the phenotype.

To be honest, it surprising recessive slate carrying varieties are not more common. A recessive blue (BB slsl) looks basically identical to a lavender (BB DD) only without the associated neurological problems. Part of it seems to be the misunderstanding of the term "recessive," as I think for some, the connotation is exceedingly negative. Recessive conjures up images like receding hairline and some thing there must be something wrong with this variety. If I were to rebrand it it would be "Aussie" or "Ozzy" slate as this is the only variety of slate in Australia.

That said, this slate gene did originate in Arizona in the 1930's, but was lost sometime after. Somehow, it ended up in the UK, Ireland, Australia, and other parts of the world. It was brought back to the United States by Kevin Porter in the 2000's.

Identifying Color Expressions

This is a frequent question... "What color is my turkey?"Well, there is a tab for that specifically which suggests using the Facebook group, Turkey Color Genetics 101. That said, if you're wondering how to do it yourself, you need to know what you're looking for...

That said, it's gonna take a minute to write out as much as I can. I will get there, but bare with me, everything is a work in progress...

Calculating Breeding Outcomes

As far as a calculator, we promised not to build one. See the next section below for the why. That said, you don't need a calculator to predict outcomes once you understand what you're doing...For the most part...

The more heterozygous pairs of alleles there are in a bird, the more outcomes you can have. If you're trying to breed for a specific color, a Mottled Slate and a Red Painted may be the worst combination to go with... Why?

A Mottled Slate tom with genotype Bb1 Ccg Dd nn with a Red Painted with Genotype Bb cmc Rr gives far too many outcomes...

At locus 2, you have all four alleles with possible combinations being Cc, Ccm, cgc, and cgcm

All hens will express Narragansett and all males will not, giving more variation

Finally, there is split Dd and Rr, so all offspring could be dd or Dd and/or RR or Rr.

This you can expect the odds to be 1 in 62.5 for a specific gene combination.

So, what you want are better odds... Which means not just breeding at random to see what happens! A best practice is to figure out what end result you want and instead of just breeding at random, select intentionally what you need to get to that point.

Let's say you want to breed a red palm... The genotype of a red palm is b1b1 cgcg nn/n- rr... That's step 1, so what is step 2?

You can technically get there in two generations with a royal palm x bourbon red cross. Those offspring could breed and produce red palms... But those offspring would have many heterozygous pairs: bb1 Ccg Nn Rr... Rather than 1/4 odds, it is 1/250 odds to get a red palm... So, you've gotta make a decision... Hope you get at least 250 eggs to hatch and that the odds work out how you want them to, OR, find calicos and use those...

The clear distinction I want to make with this section... Random breeding trying to get a specific result is very inefficient. You can get very lucky... But it's more effective to put the thought and time into figuring out a plan.

We do offer the service of creating a custom breeding plan. We can work off of the flock you currently have or make suggestions for birds to obtain if you lack the necessary genetics to get there now.

The Godfather of Turkey Color Genetics

Kevin Porter has spent years documenting turkey varieties, phenotypes, genotypes, breeding outcomes, and color inheritance.

Visit PorterTurkeys.com