| Inbreeding / Linebreeding of Purebred Dogs |
From a scientific point of view, linebreeding is defined as breeding two individuals containing at least one
common ancestor. This common ancestor may contribute a negligable amount to it?s descendants, or a great
amount. For example, lets say that 200 years ago a dog existed that sired a litter of 2 pups. One pup was flown
across the ocean and one stayed here. Both were bred. Now, 200 years later, the descendants of both trace
back to the father (and mother) of both. If two of these dogs were bred, the genetic influence of that original
stud dog would be minimal, but it would still be linebreeding.
common ancestor. This common ancestor may contribute a negligable amount to it?s descendants, or a great
amount. For example, lets say that 200 years ago a dog existed that sired a litter of 2 pups. One pup was flown
across the ocean and one stayed here. Both were bred. Now, 200 years later, the descendants of both trace
back to the father (and mother) of both. If two of these dogs were bred, the genetic influence of that original
stud dog would be minimal, but it would still be linebreeding.
Close linebreeding is inbreeding. Breeding parent to offspring is close linebreeding, or inbreeding (see below).
Inbreeding is generally defined as the breeding of two closely related individuals. Technically speaking, however,
it can be defined more precisely.
it can be defined more precisely.
Consider the fact that any sexually reproducing life form obtains 50% of it?s genetic material from each parent,
25% from each grandparent, 12.5% from each great grandparent, etc. Scientifically speaking, an inbred animal
contains more than 50% of it?s genetic material from one individual. For example, breeding a parent to it?s own
offspring will produce animals containing over 50% of their genetic material from the animal that is the parent
and the grandparent both. Breeding a brother to a sister will produce offspring with up to 50% of their genetic
material from one grandparent and at least 50% from the other - They will only have 2 grandparents. It is so
unlikely as to not even be worth considering that they would get exactly 50% from each, but if they did, they
would be full-siblings to their own parents and they would not technically be inbred, but there would be no way to
tell.
25% from each grandparent, 12.5% from each great grandparent, etc. Scientifically speaking, an inbred animal
contains more than 50% of it?s genetic material from one individual. For example, breeding a parent to it?s own
offspring will produce animals containing over 50% of their genetic material from the animal that is the parent
and the grandparent both. Breeding a brother to a sister will produce offspring with up to 50% of their genetic
material from one grandparent and at least 50% from the other - They will only have 2 grandparents. It is so
unlikely as to not even be worth considering that they would get exactly 50% from each, but if they did, they
would be full-siblings to their own parents and they would not technically be inbred, but there would be no way to
tell.
Inbreeding can be catastrophic or it can be the absolutely best way to improve and standardize a line. Any hidden,
recessive traits in the ancestor providing the majority of the offspring?s genetic material are reasonably likely
to show up. These traits can be good or bad. Oftentimes, "test-breedings" are done to verify the superiority of a
particular strain or to check for recessive problems. Any weaknesses, faults, deformities, etc. are likely to show
up. If a truly superior line or strain has been developed, containing only desireable qualities, these desireable
qualities will be seen in the resulting offspring.
recessive traits in the ancestor providing the majority of the offspring?s genetic material are reasonably likely
to show up. These traits can be good or bad. Oftentimes, "test-breedings" are done to verify the superiority of a
particular strain or to check for recessive problems. Any weaknesses, faults, deformities, etc. are likely to show
up. If a truly superior line or strain has been developed, containing only desireable qualities, these desireable
qualities will be seen in the resulting offspring.
There are 2 specific (and 1 general) examples I can site;
The white mice used in labs, called "Jaxon mice", have been inbred parent to offspring and brother to sister for
over 1000 generations. At this point, they are so identical as to be virtual clones of eachother. The only
difference to be found is that there are both males and females. This is why they are valuable for research; there
are less variables in any experiment as all the "test subjects" are genetically identical, and should respond alike
to any stimuli. It is also a fact that these mice are healthy albinos.
over 1000 generations. At this point, they are so identical as to be virtual clones of eachother. The only
difference to be found is that there are both males and females. This is why they are valuable for research; there
are less variables in any experiment as all the "test subjects" are genetically identical, and should respond alike
to any stimuli. It is also a fact that these mice are healthy albinos.
Guiding Eyes For The Blind, Inc., located in San Raphael, Ca., has developed 3 strains of German Shepherd Dogs to
guide the blind. One of these strains, the "Frankie line" is being inbred to produce offspring containing as much of
Frankie?s genetic material as possible, some having as high as 96% of their genetic material from Frankie. And
these dogs are happy, healthy, well-adjusted and successfully guiding their blind owners through city traffic, etc.
(Another strain is geared to linebreeding to produce puppies that have as close to exactly 50% of Frankie?s genes
as possible-linebreeding. The third strain is based on another dog [Orthos], and they are trying to increase the
percentage of his genes in the puppies to the highest possible extent, while still maintaining something genetically
from Frankie.)
guide the blind. One of these strains, the "Frankie line" is being inbred to produce offspring containing as much of
Frankie?s genetic material as possible, some having as high as 96% of their genetic material from Frankie. And
these dogs are happy, healthy, well-adjusted and successfully guiding their blind owners through city traffic, etc.
(Another strain is geared to linebreeding to produce puppies that have as close to exactly 50% of Frankie?s genes
as possible-linebreeding. The third strain is based on another dog [Orthos], and they are trying to increase the
percentage of his genes in the puppies to the highest possible extent, while still maintaining something genetically
from Frankie.)
Also, many farmers/stock-breeders will buy a superior bull, buck, ram or stallion and breed his daughters back to
him. Their female stock is improved in this way, and after a generation or two (or three?), the stud is sold,
leaving behind a much more valuable female breeding population, and then a new superior stud is found, and the
process restarted.
him. Their female stock is improved in this way, and after a generation or two (or three?), the stud is sold,
leaving behind a much more valuable female breeding population, and then a new superior stud is found, and the
process restarted.
It is important to note, however, that in the pet market, most inbred litters occur because of the wrong reasons.
Accidental breedings for example, or a male pup didn?t get sold and it was a cheap way for mom to have another
litter, etc. Inbreeding should only be attempted by knowledgable, experienced breeders, and even then, some
unexpected surprises may be lurking!
Accidental breedings for example, or a male pup didn?t get sold and it was a cheap way for mom to have another
litter, etc. Inbreeding should only be attempted by knowledgable, experienced breeders, and even then, some
unexpected surprises may be lurking!
In summary, inbreeding occurs when offspring are produced containing more than 50% of their genetic material
from one individual; The totality of qualities belonging to that individual AND the knowledge of the breeder will
determine whether this is a horrible thing or a wonderful thing.
from one individual; The totality of qualities belonging to that individual AND the knowledge of the breeder will
determine whether this is a horrible thing or a wonderful thing.
| "Written by Lysa Rector, |