Breeding strategies with genotypes ; inheritance and tips
Victory Best Kittel was tested TTTT for the new CRY1 gene
A large number of markers or SNPs in the pigeon genome have already been investigated for possible relationships with performance performance in competitions. In addition to the first known LDHA gene, more such genes such as DRD4 and very recently CRY1 have been shown as valuable quality markers. For a feather keratin gene, a difference was seen between short and long range. Many other genes have already been investigated with no clearly demonstrated association with competition performance such as myostatin, creatine kinase, alpha A globin, LDHB genes. And research in this area continues. The three genes that show a clear connection are also interesting to test in practice for breeding programs because the beneficial variants are relatively rare in themselves. This makes it relatively interesting because there is still progress to be made. Suppose we find a gene with an advantage for good performance and 80% of the pigeons have this gene. This last gene in itself would not be interesting to test because most pigeons possess it. At the same time, it also indicates that these genes will not be absolutely necessary to have a top pigeon. Because if this were the case, the average variants of the gene would have been selected out long ago. With many genes this will certainly have happened during the evolution of a racing pigeon.
In the meantime, the value of these genes has often surfaced in practice and these quality markers are increasingly tested and used to try to breed better pigeons. Hence this article to help with how we think this can be done usefully.
First and foremost it is important to realize that these markers can help to make a difference, but of course they can only be part of breeding better pigeons. In our opinion, therefore, only taking these genes into account is unwise. In our opinion, one should try to take into account as many factors as possible when determining a breeding strategy and these genes can then be part of that. In addition, the complete selection of the 'normal' genotypes (such as BB CCCC) is also simply unwise. There are still too many good pigeons among these genotypes to do this. Pairing the advantageous genotypes on top pigeons with such genotypes is, see further explanations and explanations below. When determining the links, it is important to have an understanding of Mendel's laws and their explanation. You must therefore understand that a pigeon has every chromosome in duplicate (one from the father and one from the mother), which is why all genes are also present in the double (which always results in two letters, eg AA).
Which useful markers do we currently have available and what is their value according to our experience and suspicions?
The oldest and best known is lactate dehydrogenase A or LDHA. There are 3 genotypes, viz.
AA ; rare and most sought after
BB ; the 'normal' and most common
According to what we can now see after many tests together with additional research, this 'A' marker is more common in winners (pigeons that make the difference) in races with several hours of flying (less in sprint) and in pigeons that are raced more ( basketing weekly). Globally, the top extreme middle and long distance pigeons are the animals where we find these genotypes most often. It is also clearly advantageous in extreme long distance pigeons. The mutation in this lactic acid enzyme gene is located in the intron of this gene (meaning before the actual gene starts with the amino acid sequence) and has to do with expression of the gene (how much of the gene is transcribed). This has already been shown from an expression study, in simple words the 'A' pigeons have on average more of this enzyme. The explanation remains the same here; these pigeons probably have less lactic acid and therefore less pain in the muscles during prolonged exertion.
Practically speaking, this gene simply follows Mendel's laws, e.g. with the following crosses you get these results:
- AA x BB
100% of the offspring are AB
- AB x BB
50% chance of AB
50% chance of BB
- AA x AA
The second gene already established is the dopamine receptor gene type 4. This gene has to do with the character of the pigeon. This gene is more complex and somewhat special because it concerns two different markers within the same gene. In our notation, the first two letters refer to the first mutation and the last two to the second place in the gene. The “T” mutation in the first place eg CTCC probably has to do with more exploration behaviour, more daring, courage, faster flying alone. We find this mutation more in winners at all distances (speed to extreme long distance) but typically also in mass releases. We therefore suspect that these pigeons want to free themselves from the bunch more easily.
We clearly find the “T” mutation in second place, eg CCCT, the most in extreme long distance pigeons. We suspect that this mutation may have to do with persistence.
Within this gene there are the following genotypes;
CCCC ; the 'normal' genotype
TTCC ; homozygous for the mutation in the first place
CCTT ; homozygous for the second mutation
CTCT ; this genotype is by far the best genotype for competition performance
With this gene, it is important to note that the two 'T' mutations do not co-exist in the same gene, and it is unlikely that they ever will. Genotypes such as TTCT, CTTT, TTTT will therefore normally not be found. If you would have received such a result from a lab, we strongly recommend that you have this retested and/or have another lab perform the test. In general, try to work with a reliable quality lab. Human errors can always be made and that is why it is also grateful with DNA that retesting is always easily possible, but we have already discovered that there are probably scammers active in this domain.
Mendel's laws of course apply here too, but it is a bit more complex because the two markers C in first place and T in second place will always inherit together. This is also the case with T in first place and C in second place.
Examples of crossings;
- CCTT x CCCC
- CCCC x TTCC
- CTCC x CCCC
How do you breed pigeons with CTCT? This is what you actually want if you want to breed racing pigeons for better racing performance.
- TTCC x CCTT
- CTCT x CTCT
- CTCC x CCCT
The new third gene found is a gene for a cryptochrome 1 protein in the retina of the eye. Such proteins have been associated, among other things, with day-night rhythm and magnetoreception of birds. The advantageous TT mutation in this gene is also located in the intron, so the hypothesis again goes in the direction of gene expression. The normal AG is also the most common here. Here again we are talking about a simple inheritance as we saw with the LDHA gene. Don't be fooled by the four letters, the first and last two letters always inherit together.
Following genotypes exist;
AGAG ; the 'normal' that most pigeons possess (be careful here too there are still very good pigeons)
TTTT ; exceptional and very beneficial both for performance and for breeding
- AGAG x TTTT
- AGTT x AGAG
A possible breeding strategy is to try to breed with homozygotes of the good variants eg AA for LDHA or TTCC or CCTT for DRD4. This is because these pigeons in fact always give a good variant to an offspring. After that, it always seems important to us to extensively test and select these pigeons at the competitions. It is also interesting to intentionally link dominant breeding pigeons that lack advantageous genes to pigeons with genes. In general it is statistically interesting to breed more good genes in your pigeon colony. This increases your chances in percentage terms.
Hopefully this explanation was helpful to you.
If you wish to test pigeons, you can do this directly on the website www.pigen.be
You can register and immediately request your DNA with the ring numbers for the pigeons to be tested.