I think perhaps some posts were deleted due to inflammatory remarks, hence the response of judgmental.
Like Ren mentioned, there was originally 1 female Syrian and her brood caught in the wild. That female began to cull her young and was euthanized. The
offspring were bred together. So all of the very early stock of hamsters were all related. However, you can separate the offspring into 2 groups to create lines and breed within those groups. After enough generations, the populations have less in common genetically. If desired, you can outcross between the 2 lines.
Here's an example of how helpful linebreeding can be: The Dark Gray hamster. The color is like a Golden in grayscale and very pretty. It is, according to breeders, a very difficult gene and few work with it because of that difficulty. Breeders have found that DG hamsters are sometimes smaller as pups and weigh less as adults. There seems to be a higher mortality rate for DG pups. Mind you, this isn't an "across the board" result, but I've talked to 3 DG breeders and seems to happen often.
So to get more DG, you'll first need DG or DG carriers. And then you'll breed them together and hope for more DG. Because DG pups show up less often, it is also hard to test breed for the gene, making it difficult to remove hamsters from the DG line. (It is too unstable to have in other lines, according to the breeders I spoke to.) You can always add more hamsters in (outcrossing) to create more carriers, but ultimately you'll be breeding distantly related hamsters. In the case of DG, linebreeding is one of the few ways to keep the color going.
Cheetahs are a great example of why closely related populations shouldn't breed. But Cheetahs are also a small population already. There isn't a lot of numbers, and therefore less genetic variety exists already.
Breeders are fortunate with hamsters because there are larger base populations and variety to work with to get better results. Ethical breeders will not continue to breed a line of hamsters that have problems. For example, an ethical, reputable breeder wouldn't breed from an anophthalmic white just because it increases the chances of producing Roans. An ethical breeder wouldn't purposefully keep breeding a line that produces hydrocephalic hamsters either. However, some people still do it. Makes places like this forum very helpful to inform and teach people to ask questions about their hamster's background!
