Jarrett Roundhead (dark side) bullstag from Bill Hull by RA Superfly Gamefarm
Game fowl purity. Quite an overused phrase, and may even sound boring to many of us. Why, because many would say there you are again, rehashing what had already been rehashed for countless number of times.
Yes, it is true that game fowl purity has become one of the most talked about and controversial topics in game fowl breeding. In fact, there are more disagreements in this topic as there are in other game fowl breeding and management topics.
Why disagreements? Simple. If I say that a particular fowl is pure, not a few breeders will react with grave concern and tell me point blank that there is no such thing as pure chicken. True! Look. Except for clones, there are no two individuals that are exactly phenotypically and genetically alike. No, not even identical twins.
Now, even if two chickens are alike in most aspects, they differ in the way they express their traits because of differences in environment. As breeding experts say, no two individuals are in exactly the same environment at exactly the same time. Believe it? You better.
We may be able to provide the best environment to the fowls for their optimal development, but there always are micro-differences in the environment that may spell the difference between good and mediocre performance.
Now, what am I trying to drive at? Well, I am not about to refute the claim that no two chickens are alike, because it is true. However, if we widen our horizon, we will be able to see things from a clearer perspective.
You see, there are different categories of fowl purity. From a simplistic point of view, game fowls are different from one another because all of them are crosses. Of course, with crossing, we mean the mating of fowls from different bloodlines. We know pretty well that the resulting progeny is a combination of the original bloodlines used.
With indiscriminate crossing, the fowls become even more crossed up, more often than not causing trouble to the breeder rather than genetic progress.
Back to widening our breeding horizon. More often than not, we concern ourselves basically with only one category – that is, that every bloodline is a product of crossing and, therefore is not pure. What we fail to recognize is that purity is not always concerned with the totality of the chicken.
This may be difficult to believe or understand, but I can take just one characteristic and say that my fowl is pure – at least for the said characteristic. I can extend this to more traits, and conclude after a while that my fowls are pure as far as these traits are concerned. Although almost impossible under the conditions that we do game fowl breeding, I can even include all traits and still say that my fowl’s pure!
If we examine this closely, we will note that the extent of purity of the game fowl is based how homozygous their gene pairs or allelic pairs are. The more gene pairs are homozygous, the purer the fowl is. Just what do we mean by homozygous? Ok. Let’s go back to the chromosomes.
Chromosomes are the ones that contain the genes, and they come in pairs – hence, we have the ZZ chromosomes for males and ZW chromosomes for females. The chicken has 37 pairs of chromosomes, 36 of which are for the different traits, while the 37th is for the gender of the bird and some of its characteristics linked to it.
There are questions: What are in the genes and chromosomes? What do they have to do with genetic purity in chickens? Will they answer our question on the other category of purity that we want to get across? They should, but in the next post. Wait for it!
CATEGORIES OF PURITY – PART 2
Thompson White broodcock by RA Superfly Gamefarm
What are in the genes and chromosomes? What do they have to do with genetic purity in chickens? What is the other category of purity that we want to put across?
In each of the chromosomes in a pair are genes controlling various traits. The gene for a particular trait in one of the chromosome pair may be for the same type as that in the other chromosome in a pair, or different. If they are the same, then the fowl is homozygous for the trait; and if different, the fowl is said to be heterozygous.
So, what’s the fuss if a fowl is homozygous or heterozygous? If a fowl is homozygous, its phenotype is the same as its genotype. Meaning, if a fowl carries the grey plumage in both genes controlling plumage color in the chromosome pair (the fowl is homozygous for the grey plumage color), then the fowl appears as grey.
If the fowl carries the grey plumage color in one of its genes and red in the other (the fowl is heterozygous for the grey plumage color), the fowl appears as grey, but at the same time carries the gene for red plumage color – the fowl is not pure as far as plumage color is concerned. Now, its phenotype is grey, but its genotype is grey and red.
homozygous fowl heterozygous fowl
appearance: grey appearance: grey
genes: Z – grey genes: Z – grey
W – grey W – red
be expected: breeds true to type more likely to produce
If the purity of a fowl is extended in as many characteristics as possible, then the fowl becomes more homozygous – it is expected to express in its phenotype whatever genes it carries. What’s more – if used as a brood fowl, such fowl is more able to stamp its good (and bad) characteristics in its progeny, which means that it is prepotent. In more popular terms, the bird is said to breed true to its type. A brood fowl like this is very important if you want to see its characteristics in its progeny.
The question is: how can we have homozygous brood fowls? Easy. If you are serious in your game fowl breeding, you’d know what I mean. Of course, I am referring to inbreeding, outbreeding and outcrossing, the stuff you use whenever you feel like producing seed fowls. Well, actually, we use only inbreeding in producing seed fowls. It really depends upon what fowls we have, and what we intend to do.
If we are into seed fowl production, then we use inbreeding. The closer the relationship of the birds paired, the quicker each generation becomes purer. If you will be able to inbreed your chickens for so many generations (16 generations, minimum), you will be able to produce the purest of all chickens.
Easy? No. In fact, if you are not yet that experienced and knowledgeable in breeding game fowls, I am definitely not going to allow you to do this. Why? It’s going to give you loads of headache rather than help you win even in hackfights. Besides, we know that we cannot closely inbreed chickens for 16 generations!
While close inbreeding has its vital contributions to game fowl improvement, it is risky to implement in view of the negative effects it has on birds. First, the reproduction rate of the fowls may literally come close to zero. This may happen in small flocks where selection is almost non-existent.
When we say reproductive rate, we include all the factors that contribute to it – fertility, hatchability, chick survival and broodfowl vigor. The fowls become genetically purer all right, but not without these major setbacks. As we often say, you can’t have everything. You get something, but you also lose something in exchange. Unfortunately, to many breeders, losing seems to be the order of the day when it comes to inbreeding, rather than gaining.
Now back to categories of purity. As mentioned earlier, the first is the impossibility of it, because of the assumption that all fowls are crosses. The second has to do with the inner science of breeding that deals with the reality that the fowl, like any other living organism, has a definite number of genes that control its appearance and behavior.
These genes are in pairs, each pair influencing the expression of a particular trait. The pairs are independent of each other, although in some traits, expression depends upon the influence of numerous gene pairs. Because of the independence of gene pairs particularly in simply inherited traits, it is possible that a pair is homozygous while the rest are not. This serves as the basis of fowl purity, in the micro-sense of the word. A fowl can be pure only in one trait, two traits, three, or many traits!