Inbreeding

[Ludwig Venter]

In the mid 90's, I got myself 3 male guppies and 8 females, 1 Male platy & 3 Female and 1 male mollie & 2 females.....I now have litterary thousands of each of these originating from that common source......Just how much inbreeding can a species tollerate before defects are shown.... Mine are all prize specimens and hardier than the average....

 

[Ficious]

youre probably going to find out, im sure

 

[Corleone]

Guppies are so inbred to start with it might not make that much difference. There's a couple dog breeders in my family who say four generations, but I have no idea where they get that number.

 

[Ludwig Venter]

Guppies are so inbred to start with it might not make that much difference. There's a couple dog breeders in my family who say four generations, but I have no idea where they get that number.

Yea... I know in dog breeding the bad traits (hip displacement and the like) are accentuated in each "inbred" generation...... Guppies in at least 12 years with an average of 26 day gestation periods must be thousands generations deep & I've noticed no real deviations....

 

[davefish]

The effects of inbreeding vary a lot from species to species. As you have bred thousands of guppies from just 11, they certainly will be inbred, however that doesn't necessarily mean that they will show any negative effects. I suspect that a process called purging is going on here. Basically, individuals who have inherited 'bad genes' from their parents will die before or shortly after birth or be less successful breeders. This removes the 'bad genes' from the population. As Corleone pointed out, guppies are already pretty inbred so I suspect this has been happening for a long time. Alternatively, you could just have been lucky and picked some genetically healthy guppies originally!

Interestingly, selectively breeding guppies to be 'prettier' is likely to increase the effects of inbreeding because it is not the 'fittest' individuals which are allowed to breed, but the prettiest. These individuals may have 'bad genes' but still be bred from (this goes on a lot in dogs).