Moderate levels of genetic diversity were observed for both of these indices in surveys of two cheetah subspecies, one from South Africa and one from East Africa.Back calculation from the extent of accumulation of DNA diversity based on observed mutation rates for VNTR (variable number of tandem repeats) loci and mitochondrial DNA supports a hypothesis of an ancient Pleistocene bottleneck that rendered the cheetah depauperate in genetic variation for nuclear coding loci but would allow sufficient time for partial reconstitution of more rapidly evolving genomic DNA segments.
Females frequently mate with several different males while they are fertile and are then likely to bear a single litter of cubs fathered by multiple males making many of the cubs within a single litter only half-siblings.This discovery has important implications for the conservation of these endangered animals.Though it conflicts with the idea that cheaters never prosper, evolutionary theory suggests that, in this case, cheating may be exactly what the doctor ordered... How did biologist Dada Gottelli and her colleagues at the Zoological Society of London figure out that female cheetahs were fooling around with so many different suitors? Biologists have rarely caught cheetahs "in the act," but they have been able to pick up what cheetahs leave behind in their daily routine: poop. And cheetahs, like us, get half of their DNA from their mother and half from their father.So Gottelli's team collected feces from mothers, their cubs, and potential fathers and then extracted and analyzed the DNA to perform paternity tests on the cubs.Females seem to mate with individuals from far-flung regions, meaning that the cubs' fathers are only distantly related to one another.
Furthermore, female cheetahs don't even return to the same males year after year: consecutive litters from the same mother all had different sets of fathers.
The timing of a bottleneck is difficult to assess, but certain aspects of the cheetah's natural history suggest it may have occurred near the end of the last ice age (late Pleistocene, approximately 10,000 years ago), when a remarkable extinction of large vertebrates occurred on several continents.
To further define the timing of such a bottleneck, the character of genetic diversity for two rapidly evolving DNA sequences, mitochondrial DNA and hypervariable minisatellite loci, was examined.
In this case the female who mated multiple times and had variable offspring would pass her genes on to the next generation, while the female who mated singly and had a more uniform litter would not.
Over time, if this imbalance persisted, natural selection would favor females with genetically variable litters and hence, females who engaged in multiple matings.
Biologists hypothesize that in an unpredictable environment, like the Serengeti, having variable offspring would have been advantageous to a female cheetah.