Females can also out-number males as much as 10:1 in many species; this too acts as a genetic bottleneck and further decreases the genetic variation of the species.
Such strategies are common in endangered species re-introduction scenarios, where dramatic population declines result in a genetic bottleneck and the loss of genetic diversity.
However, since the modern purebred wisent are descended from less than 2 dozen individuals, this has resulted in a significant genetic bottleneck for the purebred wisent.
The researchers claim that this case of unicoloniality can not be explained by loss of their genetic diversity due to the genetic bottleneck of the imported ants.
According to the genetic bottleneck theory, between 50,000 and 100,000 years ago, human populations sharply decreased to 3,00010,000 surviving individuals.