Single-celled organisms, like bacteria and amoeba, reproduce asexually, primarily through a process called binary fission. This means they split into two identical copies of themselves. Therefore, in most cases, a single-celled organism is genetically identical to its parent.

However, there are a few ways in which differences can arise:

* Mutations: While rare, mutations can occur during DNA replication. These changes in the DNA sequence can lead to differences between the parent and offspring.

* Environmental Factors: Some single-celled organisms can adapt to their environment through changes in gene expression. This means they can alter how their genes are used, leading to functional differences from their parent. These changes are not inherited but occur within the individual's lifetime.

* Horizontal Gene Transfer: This process, common in bacteria, involves the transfer of genetic material directly from one organism to another, not just through parent to offspring. This can introduce new genes and traits into the offspring that the parent didn't possess.

Overall, differences between single-celled organisms and their parents are relatively infrequent, and often arise through random mutations or environmental influences. While these differences can be significant, they are generally not as pronounced as the differences seen in offspring produced through sexual reproduction in multicellular organisms.