Just thought that I would post this article here that I found, it is written by Gypsi Nirvana, although I have sourced this from another site.
IN-BREEDING:... is the breeding together of closely related plants or animals, for example mother/son, father/daughter and sibling/sibling crossings. For breeders, it is a useful way of fixing traits into a strain, breed or variety.
Inbreeding does hold some potential problems.
The limited gene pool caused by continued inbreeding means that deleterious or harmful genes become widespread and the breed then loses its vigour.
Laboratory animal suppliers depend on this to create very uniform strains of animals which are immuno-depressed or breed true for one particular disorder or another, for example: epilepsy for testing drugs for epilepsy.....
Such animals are so inbred as to be genetically identical (virtually clones!), a situation normally only seen in identical twins. Similarly, a controlled amount of inbreeding can be used to fix desirable traits in farm livestock and plants, for example: milk yields and in cannabis, density of buds, buds to leaf ratios, rate of growth, colour, flavour etc.
...and on to..:Natural Occurrence of Inbreeding......
A wolf pack, which is totally isolated from other wolf packs, by geographical or other factors, can become very inbred.....Also so can be said of cannabis varieties isolated in remote locations up in the hills and valley's around the world that are inbred successively over many generations to create what is know as a 'Land-Race' variety or strain as say in the Parvati Valley in India with many varieties/strains named after their location of cultivation...(the village name)...
.....LANDRACE: refers to a race of animals or plants ideally suited for the land (environment) in which they live and, in some cases, work; they often develop naturally with minimal assistance or guidance from humans (or from humans using traditional rather than modern breeding methods), hence are usually older, less modern races.
....The effect of any harmful or undesirable genes becomes noticeable in later generations.... as the majority of the offspring inherit these genes....
Scientists have discovered that Wolves, even if living in different areas, are genetically very...very similar. Quite obviously the gradual and relentless desolation of their natural habitat has drastically reduced wolf numbers in the past creating a definite genetic bottleneck.
...Let's look at the Wolf....:the lack of genetic diversity makes them susceptible to disease... since they lack the ability to resist certain viruses.
Extreme inbreeding affects their reproductive success with small litter sizes and high mortality rates.....Some scientists hope that they can developed a much more varied gene pool by introducing Wolves from other areas into the inbred Wolf Packs....
Cannabis can also suffer from being inbred over a protracted period of time by loosing hybrid vigour and often developing various mutations of growth....
Another animal suffering from the effects of inbreeding is the Giant Panda. As with the Wolf, this has led to poor fertility among Pandas and high infant mortality rates. As Panda populations become much more isolated from one another (mostly due to humans blocking the routes which Pandas once used to move from one area to another).....Sadly as a result Giant Pandas have greater difficulty in finding a mate with a different mix of genes and breed much less successfully.....
Within cat populations natural isolation and inbreeding has given rise to domestic breeds such as the Manx cat which developed on an island (Isle of Man) so that the gene for tailless ness...(having no tail!....Meooow!) became widespread despite the many problems(for the cat)... associated with it.
...Apart from the rare odd cat jumping off a ship on the Isle of Man, there was little out crossing and the effect of inbreeding is reflected to this day in smaller than average litter sizes,...stillbirths and spinal abnormalities which diligent cat breeders have worked so hard to eliminate.....
Some feral cat colonies have become highly inbred due to being isolated from other cats (e.g. on a remote farm) or because other potential mates in the area have been sterilized/neutered so removing them from the immediate gene pool.
Most cat workers dealing with feral or wild cats have encountered some of the effects of inbreeding. Within such colonies there may be a higher than average occurrence of certain traits..... Some are not serious, for example: A predominance of calico pattern cats.
Other inherited traits which can be found in greater than average numbers in inbred cat colonies include polydactyl (the most extreme case reported so far being an American cat with 9 toes on each foot!!), dwarfism (although dwarf female cats can have problems when trying to deliver kittens due to the kittens' head size), other structural deformities or a predisposition to certain inheritable conditions.
The ultimate result of continued inbreeding is terminal lack of vigour for cannabis or cats and probable extinction as the gene pool contracts, fertility and natural vigour decreases, abnormalities increase and mortality/mutation rates rise.
SELECTIVE BREEDING.......
...Artificial Isolation or 'Selective Breeding' produces a similar effect. When creating a new breed from an attractive mutation....
Here the gene pool is initially necessarily small with frequent crossings between related plants. Some varieties which resulted from spontaneous mutation have been fraught with problems........If we were talking about dogs we would look at problems such as hip dysplasia in the German Shepherd and Patella luxation which are more common in certain breeds and breeding lines than in others, suggesting that past inbreeding has distributed the faulty genes.
Selecting suitable outcrosses can reintroduce healthy genes, which might otherwise be lost, without adversely affecting the strain/breed as long as the outcross has mostly recessive traits....
Most all zoos that are engaged in captive breeding programs are aware of this need to outcross their own stock to animals from other collections.
...Captive (closet) plant or animal populations are at risk from inbreeding since relatively few mates are available to the animals/plants, hence zoos must borrow animals from each other in order to maintain the genetic diversity of offspring....and cannabis cultivators might share clones or seeds.....
It's plain to see that inbreeding holds problems for anyone involved in animal husbandry or cannabis cultivation - from canary fanciers to alfalfa farmers.
When certain dog breeders attempted to change the appearance of the Pug dog so that it would have a flatter face and a rounder head, this resulted in more c-sections being required and other congenital problems. A few of these dog breeds are loosing there natural ability to give birth without human assistance!....
In the dog world, a number of breeds now exhibit hereditary faults due to the over-use of a particularly popular stud which was later found to carry a gene detrimental to health. By the time the problems came to light they had already become widespread as the stud had been extensively used to try to improove the breed. In the past some breeds were crossed with dogs from different breeds in order to improve the breed, but nowadays the emphasis is on preserving breed purity....... and avoiding mongrels.
