The genome contains the plan after a being "built" is. This was in the previous parts, a second-hand picture of me ever again. But we have seen in the last part that the environment also contributes her particular batch to "build" of the animal. This environmental influence may be the case that he is the authoritative body for the development of certain characteristics. This means that inheritance can do at this point nothing concrete.
The heritability (heritability)
Consider, for example the branches of a tree, it soon becomes clear that has not defined its genetic material, which branch shall grow out exactly how thick it is, and when he brings new cross-shoots. The genome is describing only behave according to what rules the tree, when exposed to wind, sun and Astabrüchen. What ultimately comes out of it then provides each different, unique, even if there are two trees with identical genetic material. Two other examples, we also know from the people: the fingerprint and the iris are individually different from person to person, even in identical twins. And it was at this point is mentioned again: It is not just unlikely that the iris drawings of our pigeons are not determined solely by the genotype, but individual products of nature, whose appearance in detail the impact of environmental factors and growth processes are. Say: just the details (the detail drawings of the pigeon eye, such as "speed lines" endurance lines ", ...), to which many breeders look is still all too happy to" predict inheritance strength "of racing pigeons are probably not directly from genetic material of the dove-dependent, but in large part on "environmental factors" due! are at least but the eye appearance determinants qualitatively inherited characteristics that are attributable to only a few genes. One conclusion from these few genes on the genome of a dove or to the dependent of many genes subjected to quantitative traits (such as speed) is not permitted (see also here under the heading of "linkage of genes").
The characteristic of a living being that we can strengthen or weaken due to directional selection, or, and this is also the background, the added feature of this environment through the range of variation known in genetics as a hereditary trait. That is, the feature must be able, despite the environmental variation in the phenotype to enforce identified. The relative progress
(relative to the selection limit) , the one made in the selection of one to the next generation called heritability in population genetics. This can be best with the German art word "heredity" translate.
So when the variation of the environment is extremely large, they may, as in the case of the branch structure of a tree, the genetic instructions to make behind disguised so that they would speak of a very low heritability / heritability of the branch structure of trees, as you will can breed by selection on any particular branch structure down.
in animal breeding and breeding of pigeons, we can therefore only by selection in the features of progress achieved in the genome that have a sufficient heritability. As a very important Feature that has different statements in a very low heritability is, at this point the vitality of these (eg in the book "The art of breeding" of Prof. Alfons Anker and in "The Big Book of pigeon" by Prof. van Grembergen) . So if the statements of those few scientists who once dealt specifically with racing pigeons are true then this means: A selection of vitality, although of course the average health status of the stock very beneficial and is therefore absolutely necessary, it does not improve but the genome of the animals, to an average of "more vigorous" doves. Say also two top-vital vital little animals can be drawn animals and vice versa. For mandating the property "vitality" in the genome is hardly possible.
written focusing on a few characteristics
As in earlier parts, which are so important in pigeons properties quantitatively inherited characteristics that involved in the expression of many genes. If you wanted to do it very easily, so you could only speak of a feature to which we breed: "The ability to be an ace-pigeon or 1.Konkursflieger.
This feature is a combination of many quantitatively inherited traits and therefore depends on a very large number of genes. And that fact makes us then may enable the selection special. Why?
Now, each has a quantitative trait variation (I refer here to those already shown more representation of the frequency distribution of a particular characteristic quality, such as in milk production in cows in Part 4 below). And the variation is again significantly increased by environmental variation and change. If we now operate on this trait through selection, we will indeed achieve steady progress in the improvement of the genome through the accumulation of "good" genes. But the progress per generation is smaller, the greater the variability of the feature and its heritability is the less. Also, it is difficult to assess the characteristics and reproducibility of environmental factors rel. to create separate criteria as environmental influences may limit the reproducibility strong. It should be mentioned as an example of the weather on the flights, the assessment of the property "Speed" more difficult.
addition, the assessment produced for many features nor a systematic problem:
When selecting assessment of the first characteristic (eg nest love) could, for example, only 30% meet the all the animals our criterion and remain, and in the assessment of the second characteristic (eg muscle) only 10% of all animals, and in the assessment a third characteristic (eg distance fitness) only 20% of all animals. And it could well be that meet only 0.6% (10% x 20% x 30%) of all available breeding animals, the selection tests! Say would pups from 1000, when we have some bad luck, meets all the criteria, only 6 pups! As a direct consequence
you would gewungen, selecting for one or another feature no longer as sharp. What is, however, if this feature already has a low Heritabiliät, in reference to this characteristic very quickly, on average, sinks and obtain any further breeding progress is herein.
So we quickly realized why the Breeder is extremely important that his breeding animals are not only good but very good in it as many of the important properties. After all the offspring will always deviate in both directions, and that the number of young animals at the same time in all important features is the "better" direction differ statistically already very low. Yet it goes quickly to zero as used in breeding animals that are with us the important features of only average or even below average.
In my view, the most complex of all possible selection criteria for an pigeon's ("The As-dove" or "the tip-plane") is already subject to many quantitatively inherited traits under. Therefore, the expected heritability is very low. Exactly why is achieved in the breeding of very good pigeons so slow and difficult progress. But that's why it's so exciting.
And it is precisely why it is important in my view, that our already difficult to access feature of the "peak-pilot" is not other, of which independent breeding characteristics (such as eye color, feather shapes of the cover feathers, toe color ,...) adds. Because then inevitably the selection of field suffers in our main feature, as we are not so many youngsters can grow without limit.
On the other hand, it would be very useful, this complex back to main feature less complex sub-features to speak of which it "exists". So you could keep the breeding progress in these sub-features in the eye in order not to risk large "decline". Because this danger is especially true if one has focused on the selection for the feature "AS-dove", and the performance of a particular animal were but in this case, unfortunately, are greatly influenced by some hereditary characteristics, such as an outstanding vigor and hybrid power .
And at this point we leave the path of the known. What they may be in the eye to remember piece of "character states". Tradition Embossed pigeon breeders enter here often appearances such as "wing shape", "body shape", "Behavior of the tail when tilting of the Dove," "broad back ",... at. This could all well be true characteristics.
But I personally have strong doubts there that many of the above selection criteria are really effective. For how do we know how practical look at these features, the good and the bad? There have been so far as I know, no biomechanical studies that have determined the optimum body pigeons. Had these features is highly relevant for a very good flying pigeon, it should be but in the last centuries of breeding pigeons at least among the top pigeons and aces have with respect to these traits emerged very common type!
exactly
And this is despite many assertions to the contrary, just not the case! As examples I would like to add only two famous pigeons: The famous "Knook" (translates to "bone", which says quite a lot about his appearance) of De Klak, and the "Sissi" of ad Schaerlaeckens, a statement of Schaerlaeckens after very small and rather unbalanced female that to the best breeders of the 20th Century is to be expected.
Let me not be misunderstood. Sure it is optimal body shape (or more give short, medium and long distance pigeons). But when a pigeon breeding, in a manner of this body in shape, which is detrimental to flight performance (and only that but we are interested), just the flight performance of that animal even worse. Say is a selection on flight performance of a dove to me the necessary agonyty a deaf body but directly accessible!
My personal favorite for the eye to remember piece of "sub-features" are rather
- intelligent behavior and learning ability
high - a high sense of direction
- strong nesting instinct and area
- fast regeneration ability after a great effort
- Distance suitability
and finally
- Speed
particular, the regenerative capacity can, however, include not necessarily a good hereditary cardio-metabolic complex, because it simply just a special (unfortunately low inherited) could be due vitality. Therefore be recognized breeders selected only as a viable breeding animals when their offspring have those features and also by the heredity of their properties was to prove to their offspring. Otherwise, this breeding animal (no matter like how its travel services are then also have been) removed from the herd and its progeny.
But as said. Here we are no longer on the specific pre-determined by the population genetics path. Rather, it is the individual interpretation of these findings and the resulting consequences of each breeder. Here it is exciting, and that competition is between the breeders of at this point in the breed!
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