What are some examples of the universal presence of dna?

DNA is found in all living things, including bacteria, protozoa, plants, animals, and even certain viruses.

The "Blueprint" or genetic material carried by this DNA directs the cell to produce the precise proteins required for survival and function; this process is known as the "Central Dogma of Molecular Biology."

There are two main steps in it:

DNA transcription is the process by which DNA is converted into mRNA and sent to the ribosomes, which are responsible for protein synthesis in cells.

DNA Translation: The process by which ribosomes convert mRNA into amino acids and subsequently into proteins.

All living cells follow the same two steps. Additionally, all living cells follow the same set of rules for rewriting (translating) the DNA sequence into the language of amino acids (a few exceptions for some uncommon amino acids).

For instance, whether a human, bacterial, or cactus cell reads the DNA sequence that codes for the amino acid lysine, the result is lysine.

This demonstrates to us that all living cells share the same fundamental functional mechanisms provided by their DNA and that all living cells originated from the same source.

That should address your query.

Bibliography & Additional Reading: Central Dogma of DNA, Transcription, Translation, Ribosomes, Genetic Code

Examples of the universal presence of DNA include its presence in all living organisms, its role as the genetic material responsible for inheritance, and its conservation of genetic information across generations. Additionally, DNA can be found in various forms such as chromosomal DNA, mitochondrial DNA, and plasmid DNA.