Final answer:
One round of random mating after a founder/bottleneck event will increase genetic drift, as it involves the survivors' alleles being shuffled and doesn't immediately restore lost genetic diversity or introduce new mutations.
Step-by-step explanation:
After the initial founder/bottleneck event, one round of random mating will increase genetic drift, not restore genetic diversity, enhance heterozygosity, or introduce new mutations. The founder effect and bottleneck effects result in a reduced gene pool because of the random elimination of individuals and, therefore, their alleles. These events can be caused by random occurrences such as natural disasters, which can drastically reduce genetic variability within a population. While random mating among the survivors can lead to changes in allele frequencies due to chance, it does not immediately restore the diversity that was lost, nor does it typically increase heterozygosity or introduce new mutations.