Life has its own unique identity by difference between DNA content and how does an organism or alive creature can interact or process material through this world and this is a keyword for difference in feature, phenotype and things that we classify an animal in different groups.
But DNA is look like a poem book it has lots of words, lots of sentences, lots of details, but there are lots of factor that a Poem will become through a real song, and this is the way we see difference in life form that elephant and penguin are 2 difference creature with similarity in genetic content.
Lets open this subject with this fact that DNA is not the only molecule we will find in a cell as an active molecule for response against environmental changes, There are series of molecule from RNA to Protein, there are lots of regulator factor, inhibitors, Ion, lipid and signal molecule that by interaction with each other control complexity of life and make different between elephant and penguin in life!
In simple example, DNA act as a poem with lots of words, sentences and details, #RNA act as a music synthesizer and protein is the latest thing we here, and life is look like that, we experience life, experience reaction through pathogens and food and every thing with series of protein from enzyme to structural protein, and they do this process by a unique 3d and 4d conformation that is shaping them as a unique conformation for interaction with specific substrate,
all organism and live creature hast these enzyme, but conformation, speed, function, process and stability is different, because natural resource in nature are different such as difference we see in food resources in Sea, ocean, jungle and one city.
Lets me open it by more details in minimal example, Elephant and Penguin both have protein in their food basket and they need to use protein as food to growth and live but resources are different, elephant achieve it from jungle and penguin achieve it from fishing and sea food. Absolutely temperature are different in tropical jungle and north pole so penguin need to an enzyme and system that is compatible with cold air and icy environment and elephant need to compatibility with warm air and challenges that forest and other animal through jungle made for them.
This story has lots of details and we should have a unique vision through genetics content, Proteins and molecular pathways that both organism use for living in nature. But this short essay can help you have vision this question that : What is the difference between elephant and penguin DNA, only DNA?