* DNA is universal: The basic building blocks of DNA (adenine, guanine, cytosine, and thymine) are the same across all living organisms.
* Sequence length is too short: This sequence is very short. To identify an animal, scientists would need a much longer sequence, perhaps hundreds or thousands of bases.
* Species variation: Even within a species, there are variations in DNA sequences. Short sequences like this might be found in many different animals.
Think of it this way: Imagine you have a single word from a book. Can you tell what book it's from? You need a much larger chunk of text to be able to figure it out!
