How would DNA extracted from an onion be different from the DNA extracted from cauliflower? Why?

DNA extration from a onion and from a cauliflower would be different because even though all DNA is composed by the same nucleotides. The sequence of genes will be different in both onion and cauliflower. That's why a cauliflower doesn't look like a onion. The genes are responsible for making up the cauliflower and the onion.