Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?
The small number of members in a population of tigers do not allow large number of variation to occur which are essential to survival of the species. A deadly disease or calamity may cause death of all the tigers. The small number of tiger also indicates that existing tiger variants are not well adopted to the existing environment and may extinct soon.
The small numbers of surviving tigers is a cause for worry from the point of view of genetics, because if all tigers perish and become extinct, their genes will be lost forever.