The numbers I have seen done by people in the breed shows that we have lost roughly 50% of our founders. That includes just from the new imports in 87/88, which is only just over 20 years ago, and already we have lost 50% of them and some only trace back to one or two breedings or 1 or 2 offspring.
This brings us back round to Clay's point, what good is it to open the stud book to foundation stock if there is no longer plan for incorporating them into the gene pool. If BCOA wants a successful native stock program then it should also include educational opportunities to learn how to best make use of the native stock otherwise people will just dip in once and then breed away from it and get the "feel good" sensation of doing something good for the breed when in fact they have done nothing.
Genetic diversity in the Basenji breed has long been an issue that interests me. I have often wondered what is really happening in our breed to reduce gene diversity? Does bringing in additional native stock actually impact the gene diversity of the breed?
lvoss has been asking similar questions in this thread.
We know that historically the Basenji breed has suffered significant bottlenecks that contribute to loss of diversity in the gene pool.
In the first 25 years of the establishment of a breed we call Basenji (between 1936- 1961), 18 individuals who contributed unequally to the gene pool were the foundation of the breed (9 dogs & 9 bitches). Three of these were outcrossed Liberian camp-dogs. The record reveals that the Liberian camp-dogs were subjected to a controlled breeding program for more than 12 years selecting for "Basenji" traits. Only then did the get of this intensive selection effort become recognized as outcross founders. In fact, the results of the breeding program produced dogs that were exported to Zambia to be bred with purebred, registered Basenji bitches (bred down from Congo native stock) brought from England. Then those get were imported to England by Elspet Ford and to the USA by Gwen Stanich. Although they are considered to be native dogs because they were whelped in Africa, they were actually only a percentage African stock.
There were no Liberian imports (native Liberian dogs) registered as Basenjis. By the time the dogs were imported, they were heavily blended with Congolese dogs BEFORE the progeny were included in the breed registry. This outcross was done simply because some members of the fancy wanted the dominant black coat color. Once the dominant black & white was bred with Basenjis from England, there were never any back-crosses to native Liberian stock.
This is a perfect example of the comments by lvoss. Her important premise is that in order to have a significant impact, new dogs have to be desirable to breeders and the fancy. They have to contribute something positive to the breed. In the example of above, the contribution from outcrossing to Liberian dogs was the dominant black coat color.
Similarly, the example of the Congo dogs registered in 1990. The contribution they made to the breed was the brindle coat pattern. Although subsequently we can say that they also provided new breeding opportunities to steer away from fanconi; we did not know that when the dogs were imported and that was not a goal of the importation effort in 1987/1988.
Anyway, the founder effect severely reduced the genome (frequency of genes in the population) of what had been the genetically diverse EFb geographic breed.
Drastically narrowed, only the genome of the dogs used to start the breed served as the genetic foundation of the dogs named Basenji by Westerners. In this way, a gene quite rare in the EFb population may have a much higher frequency in the Basenji population; conversely, genes common in the EFb population may be infrequent or even absent from the Basenji population. We can never know what we lost or what we disproportionately magnified in the genome of the Basenji compared to that of the EFb.
Of course, that wasn't the end of the story nor was the door closed on including other EFb genes. In 1990 and in the recent two years, additional native dogs have been added to the foundation gene pool. But, the Basenji genome is still based on a small number (subset) of individuals and can never represent the EFb genome.
Several years ago a breeder interested in finding unrelated lines to use with her own line did a pedigree analysis. By studying a sample of dogs that might be of interest and were "unrelated" to her own lines, she found three significant bottlenecks and extrapolated her findings to the wider gene pool of the breed.
First, from her sample she concluded that the US Basenji gene pool was approximately eight significant foundation individuals. The foundation stock who had contributed most to the breed were :
Bongo of Blean (male)
Amatangazig of the Congo (female)
Bereke of Blean (female)
Fula of the Congo (female)
Bokoto of Blean (female)
Wau of the Congo (male)
Second, Basenjis in the US show a second significant genetic bottleneck through disproportionate use of the OTC suffix (Of the Congo) dogs. During World War II Veronica Tudor-Williams was foremost in preserving the breed at a time when the Ministry of Home Security required the compulsory destruction of all dogs. There were a handful of other breeders that maintained lines, but it was VTW who bred prolifically and exported her OTC dogs to the USA.
Third, Basenjis in the US had a significant genetic bottleneck in the 1960's and 1970's due to the use of three popular sires, two of whom were sons of the third.
Without knowing about that analysis, a number of years ago I inquired about the Basenjis that were used as the basis to make conclusions about the Basenji Genome in all the genetic research into breed origins. From that information I was able to determine that genetically Basenjis are derived (for the purpose of research) from only six founders :
three foundation sires -
Wau of the Congo
and three foundation bitches -
Amatangazig of the Congo
And a couple years ago I initiated a game on one of the Basenji chat lists to track tail male and tale female lines. This was a simply and fun exercise to illustrate a singular aspect of founder loss in our current population (it does not reveal what is happening in the middle of a pedigree nor loss of genes on the autosomal chromosomes). So, it does have limitations. But it can reveal when a founder no longer has descendants; i.e., the founder is lost to the breed and all the unique genes the founder contributed. At that time it appeared to me that there were quite a few breeders who believe that each kennel name represents a distinct genetic line. The exercises was not only fun and easy with minimum instruction, but it illustrated to many that genetic diversity is NOT determined by the number of kennel names.
These examples give us important insight into the use of native stock in our breed; the overrepresentation of individuals in the breeding program, loss of some unique breeding lines, and illustrate how much our gene pool has narrowed.
Concerning the erosion of the gene pool, it is important to know how many founders are still represented in the current Basenji population and to consider the number of generations our current dogs are away from the founder. In genetically limited populations, a certain amount of unique genetic diversity is diluted with each reproductive event through the action of genetic drift, inbreeding and artificial selection. Thus, the number of generations away from the founder becomes an issue of concern. Genetic material can be rapidly narrowed, each generation carrying a reduced level of heterozygosity as it is permanently linked by the horizontal pedigree. The average time between one generation and the next is a convenient yardstick to help us realize the relative rate of genetic attrition.
So, I still wonder if admitting new native stock EFb into the Basenji gene pool will actually help gene diversity in the long run.
I keep going back to the article by Mary Lou Kenworthy, "WHAT IS DIVERSITY REALLY?" (The Modern Basenji Worldwide, Vol. 1, No. 2, Summer 2011, page 3) and Mary Lou's statement, " If breeders create and monitor their own lines, the breed, as a whole, will prosper. No breeder can maintain diversity by himself, and any attempt to do so will lead to disaster for the breeder and the breed. It takes a network of breeders working together with individual lines to maintain diversity. "
I think she is correct.