"Linebreeding vs Out-crossing

At Bydand, we have always believed that the way to produce consistent quality is by selective
linebreeding, and we have employed it as a breeding system successfully for many years. A lot of
people simply do not understand what it is, however, so we thought we'd take the time to
explain it in some depth for those interested in learning more about it.

The best way to begin is by defining the terms as used by breeders:

Inbreeding is a systematic program of breeding closely-related animals. To breeders, this
generally refers to father/daughter, mother/son, and full sibling matings

Linebreeding is a term used only in animal husbandry to describe a less intense program of
inbreeding- usually uncle/niece and half-sibling matings. In breeders' terms, one linebreeds off
a specific animal, and that particular animal may show up multiple times in a pedigree.

Outcrossing is specifically the breeding of two unrelated inbred strains, and typically produces
hybrid vigor, but the resulting animals generally do not reproduce themselves with any
consistency, unless taken back to one of the original strains.

Outbreeding is the repeated breeding of unrelated animals, with no common ancestors for
several generations in their pedigrees, and cannot really be classified as a breeding system,
although it is widely used by novices.

A lot of people are frightened by the terms linebreeding and inbreeding, and assume that the use
of these breeding systems inevitably results in genetic problems. In fact, the opposite is often
true. By utilizing selective inbreeding, lines can be developed that are genetically free of
undesirable traits. Constant outbreeding, on the other hand, produces a situation where those
genes remain hidden until they are widely dispersed throughout the population, at which point
animals displaying the undesirable trait begin to appear everywhere in the breed, and there is
little hope of selecting away from it. So why has inbreeding, and its less intense form,
linebreeding, gotten such a bad rap?

It's simple. We are a society with a strong social taboo against incest, and we carry this taboo
over into our feelings about animals. Nature, on the other hand, has no such reservations, and
many wild populations are by definition inbred (especially in species with strong social orders)
as generally only the dominant males breed.

What about genetic degeneration- in other words, how long can one inbreed before the bottom
falls out? Geneticists have studied this both in the wild and in laboratory experiments, and
reviews, as they say, are mixed at best. Among the genetics community, one will find both
proponents and opponents of inbreeding arguing their case with equal vigor.

However, it is interesting to note that historically, many cultures have practiced inbreeding with
no evidence of genetic degeneration. Although not alone in the tradition (incestuous marriage
was also common under Greek and Roman rule) the most famous were certainly the ancient
Egyptians. During the Ptolemy Dynasty, which ruled Egypt during much of its heyday, deliberate
inbreeding was common practice among both royalty and commoners alike- examinations of
161 marriage records of commoners in the Ptolemic period reveal that 24% were among siblings.
And, astonishingly, every Pharoah from Ptolemy II to Ptolemy XII was the product of a
brother/sister marriage!

What was the result of this? Cleopatra, who ruled Egypt for twenty-one years during extremely rocky political times, was the product of nearly three hundred years of brother/sister marriages. (323B.C.- 51 B.C.) Historical records reveal her to have been both extremely beautiful and highly intelligent, with a gift for languages- in fact, Cleopatra managed to seduce not one, but two, Roman Emperors in succession, producing children by both of them and thereby ensuring the political security of Egypt. Any suggestion of inbreeding infertility is further dispelled by the fact that Cleopatra was herself one of five children born to Ptolemy XII and his wife.

In the face of that evidence, one wonders how so much negativity has come to surround the
practice of inbreeding in domestic animals. Well, several other cultures had less luck with the
practice- most notably the royalty of Spain and England…where genetic problems abounded.
Inbreeding, man has discovered the hard way, is indeed a double-edged sword.

Inbreeding cannot, in of itself, create genetic anomalies. Genes are genes, and unless they mutate, they are simply passed from one generation to the next, in either a recessive or dominant manner. What it can do is increase homozygosity, (where each gene pair at a given locus contains identical alleles of the gene) and if those alleles are deleterious, a recessive anomaly will present itself. Inbreeding does not so much create genetic problems, then as reveal them, especially recessive ones which

would otherwise remain hidden, and therefore be passed unknowingly to successive generations.
But it is also important to remember that not all recessive traits are deleterious, and desired
traits known to be recessive can be locked in just as surely by inbreeding.

One such trait is the G pairing, a simple color gene allele that causes a dog to silver out at
maturity. (It is not, in of itself, known to be deleterious, unless one wishes to breed dogs who
hold color.) Its recessive allele, g, causes the animal to maintain its early rich color, and
probably represents the original gene at that locus, with G having emerged as an incompletely
dominant mutation.

A black dog who does not silver is homozygous (pure) for gg, and does not have the dominant silvering allele in his DNA to pass on. (If he has even a single copy, he would display it, because that is what dominant means.) So in this case, assuming we wish to breed dogs that do not silver, this recessive gene would be desirable. Many of the traits that we considerable desirable in purebred dogs, indeed, many of which determine breed type- are controlled by recessive genes rather than dominant ones.

And, the most reliable way to cement these genes into a line and produce animals who display
them with consistency, is by inbreeding, or linebreeding, which is slower but somewhat less risky.

What are the risks? Well, unlike the gene that prevents a dog from silvering, or those that
produce good shoulder layback, many recessive genes cannot be seen with the naked eye, and
many are not as desirable. By linebreeding, many of those genes, if present in the genotype of
the original stock, will turn up as unpleasant surprises within the first generation or two.
Rigorous selection must be practiced in order to linebreed successfully, and this requires a
thoroughly objective eye and a willingness to health screen, both the breeding stock and the
offspring produced.

If done well, however, a linebred strain can be consistently healthier, sounder and certainly
typier than their outbred counterparts. In the game of breeding, linebreeding is like playing
poker with a stacked deck and a couple of Aces up your sleeve…it ups your odds of coming out
on top. Outbreeding, on the other hand, is all too often more like "Fifty-two Pickup".

In case this hasn't occurred to you yet, a true passion for breeding good dogs is a lot like a
compulsion to gamble, only more expensive….and the next hand is always going to be a
winner…. That's why we do it.

CH Bydand Bonny Black Maxwell Top winning Bydand Gordon Setter out of an Uncle/Niece breeding.

CH Bydand High Times Top winning Bydand English Cocker out of a full Brother/Sister breeding.