The LDHA gene and racing pigeon performance
The Promising Development of Gene Technology
While genetic engineering is fully developing and promising, one should be patient instead of immediately seeing a business model.
It won't be another 500 years before man will probably no longer have a reason to exist because of no longer needed for human reproduction. Women have long been able to give birth to full-fledged offspring from an artificially fertilised egg. Fertilisation of the egg cell can also be done with a woman's genetic material (skin cell), making the man redundant.
Human embryo cloning has succeeded before, in 2013 at Oregon Health and Science University and again in 2018 in monkeys. 👇
One and the other could cause much change. The amount of testosterone, the most dangerous substance on earth, would decrease significantly. On average, this substance causes much trouble for men, especially between 18 and 40.
E.g. there would be far fewer autocratic regimes, often driven by male lordship and rooster behaviour. There would be 12 times fewer crimes and prisons. In many communities, women have an unenviable status (hard work without a say), and they are gradually getting tired of it. Rightfully so!
Women deserve respect for their universal biological maternal qualities, crowned with empathy and caring for the weak and vulnerable. Biologically and genetically, they also happen to be the stronger sex! A recent book casts a scathing light on “the man, being the strong sex”.👉🏻 https://www.langzullenwelezen.be/nieuws/vrouwen-zijn-sterker-dan-mannen-dokter-els-dufraimont-over-het-sterke-geslacht
'... women are lucky enough to possess 2 X chromosomes. And that is what the book is mainly about. The man's Y chromosome is very tiny, making him different from the woman's. The Y chromosome uses about 70 genes and has to do with producing sperm. In the female X chromosome, there are 1,000 genes essential for egg production, brain development, and immunity. When one X chromosome malfunctions, women can use the other. And men can't. So in men, for example, you are more likely to get mental illness.👇👇
Similarly, the hens have much more to offer physically than the cocks.
They do not waste energy in the basket arguing with their travelling companions. But mainly because of their genetic advantage, they can physically and mentally do much more, such as participate in heavy races every week, cocks cannot.
Genetic engineering is thus making significant improvements. In the meantime, by analogy with genetically modified plants, one can eliminate a bad gene in mammals (humans) because of certain diseases and replace it with a healthy one.
Future developments and changes
Similarly, in pigeon racing, people have been active. They have been conducting genetic research for years into the heritability of essential, specific characteristics of the racing pigeon, which we would like to address briefly.
Pigeons are continuously selected based on speed, spatial orientation and endurance during (long) flights. However, numerous genetic and non-genetic factors affect survival and return ability, making such traits challenging to control for the fancier.
A recent 2018 study addressed the issue of the influence of the LDHA gene on a racing pigeon's survivability during racing competitions.
We explain what it is about as simply and concisely as possible.
A few terms:
- The genotype is the collection of all traits inherited from the parents.
- The phenotype is the total of all observable characteristics. (eye colour, ...). Both genotype and the influence of environmental factors determine phenotype. A gene is a piece of DNA. See image 1. Each gene describes the code of a trait, which (co)determines how one looks and how the body works. A gene contains the information to make a protein. All these proteins have a task in the body.
- An allele is a variant of a gene that carries a specific trait. For most hereditary properties, two different alleles (originating from the father or the mother) cause an inherited property to be expressed. From this, genetic polymorphism follows (poly = more, morph = shape) or the coexistence of different traits in the same population (E.g. colour plumage).
Variations in the LDHA gene (Lactate Dehydrogenase A gene) are likely to influence sport performance and return ability to race pigeons due to its role in physical and mental performance processes.
This study investigated whether there was a link between the gene LDHA and pigeon survival during races. The survivability was evaluated through the estimated breeding value = EBV or "Evaluated Breed Value". (*) over the total racing distances of each pigeon during its athletic life.
This estimated breeding value EBV is the likelihood of offspring inheriting the genetic traits. An animal's breeding value is its genetic contribution to each trait. This cannot be determined precisely - but only estimated.
These estimates of an animal's actual breeding value are called EBVs (Estimated Breeding Values).
The test distances in the study were 500, 1,000, 2,000, 3,000 and 4,000 km to recognise a possible genetic variation tied to the travelled distance (a distance phenotype).
More extended distance performance can promote better return and survival skills. The study involved 867 Japanese racing pigeons born between 1989 and 2012 and registered with the Japan Pigeon Federation.
Their pedigrees were checked over five generations, totalling 2,037 pedigrees. Subsequently, the breeding value was estimated for the pedigree based on the targeted genotypes. The rarely occurring genotypes were grouped to finally arrive at only two types, namely S+ and S-.
The hereditary expectation, which according to the Japanese federation ranking was 0.25 (25% chance of inheriting the Palmares), was also included in the calculation models in analogy with the genetic profiles of winners and non-winners in equestrian sports. Sexes, specific characteristics, species, populations, and general external appearance were compared.
In this study, the pigeon population descended from a 'confined' group raised by the Japanese army. Therefore, population stratification (= division of a research population into one or more subcategories according to, e.g. age, sex, social status, ...) was not in place.
Pigeons with the "S+" variation (allele) of the LDHA gene had a higher EBV value correlated with a longer total race distance.
I.e. they have higher survival rates (a property they can also pass on to offspring).
The specific "S+" spot on the LDHA gene may thus be helpful for gene-marker-assisted selection, allowing fanciers to maximise the quality of pigeons.
In addition, data obtained from breeding may also improve our understanding of the genetic mechanism that underlies navigation and flight ability in wild migratory bird species.
This research study investigated the relationship between the survival of racing pigeons and multiformity (polymorphism) in the already well-studied LDHA gene. Individuals with the "S+" genotype showed higher EBV of three (longest) race distance-related traits.
The lack of significant relationships between LDHA genotypes and shorter race distances may be because pigeon survival rates matter less at 500-1,000 km (most races and existing competition). The results confirm a significant relationship between LDHA polymorphisms and pigeon-return abilities.
These data are consistent with existing knowledge of LDHA function.
LDHA affects overall physical and mental performance: similar to human physiology.
For the more advanced:
This link illustrates the sugar metabolism of astrocytes.
In these brain cells [type glial cells in the hippocampus (*)], LDHA is converted to lactate, which is released to nearby neurons as a fuel source.
(*) The hippocampus plays a role in spatial navigation and long-term memory formation.
The astrocyte-neuron lactate shuttle hypothesis. The activation of nerve cells leads to the release of the neurotransmitter glutamate. Glutamate is actively taken up in astrocytes by glutamate transporters (GLT-1) and is converted into glutamine. Glutamate incorporation into astrocytes stimulates glucose uptake from surrounding capillaries via glucose transporters (GLUT1) and increases aerobic glycolysis. The degradation of intracellular glycogen stocks can also stimulate aerobic glycolysis. Pyruvate is converted to lactate by lactate dehydrogenase isoenzyme A (LDHA) and is exported from the cell by the monocarboxylate transporter 1 or 4 (MCT1/4) and transported to nerve cells via MCT2. LDHB in nerve cells coats lactate to pyruvate, which fuels oxidative phosphorylation in mitochondria. Glucose can also enter nerve cells via GLUT3 transporters.
Besides the S+ allele, there is also the M allele, which was found twice as much in Japanese racing pigeons (0.712) than in wild rock pigeons (0.334). This trend is due to the long history of artificial selection for high-speed and rapid returns from racing flights.
In the present study, the occurrence of the M allele was also higher than that of the S allele, but the presence of the latter showed a higher survival rate (i.e. higher EBV).
This result is probably due to the chosen studied property: Do we want to select speed or survivability? In particular, in the athletic life of a pigeon, accumulated total race distance implies the safe completion of many races, a factor that depends mainly on survivability.
High survivability indicates excellent navigational ability, increased endurance and improved resistance to environmental hazards (e.g. wild predators and bad weather), but not necessarily high speed.
Wild rock doves are more likely to survive (suggesting higher S-frequency) than racing pigeons, given the intense natural selective pressure on the former for traits such as foraging, seeking shelter and predator defence.
However, intensive and extensive artificial selection for high speed in racing pigeons has increased the M allele frequency at the expense of the S allele.
One can advance some hypotheses at this early research stage about how LDHA genetically affects the EBVs of accumulated total race distances.
Other essential genes that can affect pigeon performance are:
- The serotonin transporter (5-HTT) gene 👉🏻 personality, and
- The mitochondrial ATP6 gene 👉🏻 energy generation and physical fitness.
These properties are also crucial for survival.
These 5-HTT and ATP6 were examined among Japanese racing pigeons, but no polymorphism (necessary to select genetically) could be found within these two genes.
Indeed, to confirm the relationship between genetic variation and complex traits such as survivability, more candidate genes and pigeon populations are needed. However, studies of this kind will increase our knowledge regarding the genetic underpinnings of survivability and navigability in wild migratory bird species.
* Conclusion and consideration
There are reservations in academia regarding this particular study:
Although genetic engineering is fully developing and promising, one should be patient instead of immediately seeing a business model.
Moreover, the causal link between performance and genes must be bi-directional: If it was established that pigeons that do not underperform or die usually have a particular gene, it must also be shown in the other direction that a pigeon that has that gene also performs well.
This still needs to be contradicted.The research is highly complex due to the numerous interactions between the many variables. It will take a long time before people will be in a position to select efficiently based on gene markers.
Moving to the next step in this discipline of actually breeding super breeds via genetic modification (or manipulation) will come with ethical obstacles (eugenics during the war) and is still a distant dream ...
Meanwhile, we put up with the talents and intuition of many a top fancier in pigeon racing who manages to breed champions year after year through perseverance and insight. Comed feels a privileged partner to support branded breeding with, among other things, Miobol, which advances weaning by a week!
At this stage, with Miobol, it is best to unlock the full potential of our current pigeon stock's genotype before selecting or improving genes.