Genomic Assessment and Conservation Strategy for the Historical Brugse Vechter
AOBA Scientific Report – Phase I & Phase II
Abstract
The African Ornamental Breeders Association (AOBA) commissioned a comprehensive genomic study through African DNA Laboratory to evaluate the genetic integrity of the Colonial Bloodlines and the contemporary Belgian population of the Brugse Vechter (Bruges Gamefowl).
The objectives were threefold:
- to determine the level of genetic continuity with the historical Brugse Vechter;
- to identify historical introgression from other chicken breeds;
- to establish a scientific framework for the long-term restoration and conservation of the breed.
The results revealed a clear genetic distinction between the Colonial Bloodlines and the modern Belgian population. While the Colonial Bloodlines retained exceptionally high genetic integrity, several Belgian strains displayed measurable introgression from Sumatra, Malay and commercial meat-type chickens.
These findings provide AOBA with an objective scientific basis for conservation breeding and the refinement of its breed standard.
1. Introduction
The Brugse Vechter is one of Europe's oldest and most historically significant gamefowl breeds. Throughout its history, the breed has undergone numerous periods of selection, population decline and recovery.
Like many traditional livestock breeds, the Brugse Vechter has been exposed to historical crossbreeding, changing breeding objectives and regional differences in selection. These factors have inevitably influenced its genetic composition.
Recognizing the need for objective scientific data, AOBA initiated the first large-scale genomic investigation of both its Colonial Bloodlines and the modern Belgian population.
The purpose was not only to identify foreign genetic influences but also to establish a roadmap for restoring the historical genome of the Brugse Vechter.
2. Historical Background
For decades, the Belgian Brugse Vechter has been maintained by numerous independent breeders, each applying their own interpretation of the breed standard and selection criteria.
Although these efforts ensured the survival of the breed, they also resulted in considerable variation in morphology and genetic composition.
AOBA observed substantial differences between breeders and even between individual breeding pens belonging to the same breeder.
These observations highlighted the need for an objective genomic assessment.
The Colonial Bloodlines occupy a unique position within this conservation programme.
Having remained substantially less affected by historical introgression, they preserve genetic variants that have disappeared or become increasingly rare within many modern Belgian breeding lines.
Consequently, these bloodlines represent an invaluable genetic reservoir capable of restoring lost historical alleles while simultaneously introducing fresh genetic diversity into carefully managed conservation breeding programmes.
3. Materials and Methods
DNA samples were obtained from young birds hatched and raised by AOBA from hatching eggs supplied by multiple Belgian breeders and from different breeding pens.
After the birds had developed sufficient plumage, feather samples were collected directly by AOBA from each individual cock and hen.
This standardized sampling procedure ensured consistent DNA collection while representing multiple independent Belgian breeding lines.
Genomic analyses were performed by African DNA Laboratory using:
- High-density SNP microarrays
- Locus detection
- Genomic admixture mapping
These methods enabled the identification of breed-associated genetic loci, estimation of ancestral genomic contributions and detection of historical introgression.
4. Genomic Admixture Results
Genomic admixture analysis demonstrated a clear distinction between the Colonial Bloodlines and the modern Belgian population.
The Colonial G1B1 and G1B2 Bloodlines retained more than 99% genetic integrity, remaining highly homogeneous and representative of the historical Brugse Vechter.
The Colonial G1B3 Bloodline retained more than 85% genetic integrity, with up to 12.5% Malay ancestry.
In contrast, the Belgian population exhibited measurable introgression.
Some strains contained:
- up to 12.5% Sumatra ancestry
- up to 12.5% Malay ancestry
- approximately 6% commercial meat-type chicken ancestry
The genomic analyses identified multiple loci associated with these ancestral contributions, including:
- Extended Black (E)
- Multiple Spur (Ms)
- Pea Comb (P)
- Walnut Comb
- ISPD
- MTM1
- SFRP2
- Quantitative Trait Loci (QTLs) on GGA1, GGA2 and the Z chromosome.
5. Strain-Level Genetic Breakdown
Genetic introgression varied considerably among Belgian breeding lines.
Breeding line Genetic findings
- JM 6% commercial meat-type • 6% Malay
- JDM 6% commercial meat-type • 6% Malay
- AK 6–12.5% commercial meat-type • 6% Malay
- RP>12.5% Malay
- DVE 12.5–25% Sumatra • 6% Malay
- PVB 6–12% commercial meat-type • 6% Malay
- EE 6–12% commercial meat-type • 6% Malay
Because eggs originated from different breeders and separate breeding pens, these percentages naturally varied.
The results clearly demonstrate that the Belgian Brugse Vechter population is genetically heterogeneous.
6. Genotype versus Phenotype
A clear distinction must be made between genotype and phenotype.
The genotype represents the genetic makeup (DNA) of the bird.
The phenotype consists of observable characteristics such as body conformation, comb type, plumage colour and skin pigmentation.
Phenotypes result from both genetic inheritance and environmental influences.
Therefore, birds with similar external appearances may possess different genetic backgrounds.
For this reason, AOBA considers genomic analysis an essential complement to traditional phenotypic evaluation.
7. Breed Standard Implications
The study demonstrated that significant non-historical genetic influence is primarily associated with black-skinned and strongly pigmented individuals.
Consequently, AOBA has decided to refine its breed standard.
Individuals expressing fibromelanistic (black-skinned) and strongly pigmented phenotypes will no longer be accepted within the official AOBA breeding programme or breed standard.
This decision is based entirely on genomic evidence and reflects AOBA's commitment to preserving the historical genetic identity of the Brugse Vechter.
8. Breed Conservation Strategy
The purpose of this study is not to discredit breeders or their breeding efforts.
On the contrary, the results demonstrate that decades of independent selection have produced varying degrees of historical introgression within the Belgian population.
By identifying these genetic patterns, AOBA seeks to provide breeders with objective scientific information that can guide future conservation breeding.
The ultimate goal is not exclusion, but the gradual restoration and preservation of the historical Brugse Vechter genome.
Reducing historical introgression through carefully planned breeding is fundamental to maintaining breed purity, preserving valuable historical characteristics and protecting the genetic identity of this heritage breed.
9. Beyond Introgression: Defining the Historical Brugse Vechter
The first phase of AOBA's research successfully identified foreign genetic influences.
However, this answers only part of the scientific question.
Identifying Sumatra, Malay or commercial meat-type ancestry does not automatically reveal the original genetic foundation of the Brugse Vechter.
The next challenge is therefore to determine:
What constitutes the authentic historical Brugse Vechter genome?
10. Building a European Reference Population
To answer this question, AOBA proposes expanding its genomic research by comparing the Colonial Bloodlines with historically related European gamefowl breeds.
Potential reference populations include:
- Combattant du Nord
- Luikse Vechter
Additional historical European gamefowl populations may also be incorporated where historical documentation supports their relevance.
Such comparisons could help identify the ancestral genetic components shared by these historical breeds and contribute to reconstructing the historical genetic profile of the Brugse Vechter.
11. Future Research
Future objectives include:
- expanding genomic testing to additional Colonial Bloodlines;
- strengthening international scientific collaboration;
- establishing a comprehensive genomic reference database;
- comparing the Brugse Vechter with related European gamefowl breeds;
- performing Principal Component Analysis (PCA);
- reconstructing phylogenetic relationships;
- conducting Identity-by-Descent (IBD) analysis;
- applying Whole Genome Sequencing (WGS) to obtain higher-resolution genomic data.
These studies will provide an increasingly accurate understanding of the historical evolution of the Brugse Vechter.
12. Conclusion
This study demonstrates a clear genetic divergence between the Colonial Bloodlines and parts of the contemporary Belgian population.
It confirms that the Belgian population is genetically heterogeneous and reflects decades of independent breeding and selection.
More importantly, the study marks the beginning of a long-term scientific conservation programme.
The first phase identified historical introgression.
The next phase aims to define the original genetic foundation of the Brugse Vechter by comparing it with the closest surviving historical European gamefowl populations.
By combining genomic science with responsible conservation breeding, AOBA seeks not only to preserve the Brugse Vechter as a breed but to restore its historical genetic identity for future generations.
