GGTAC is a sequence of nucleotides found in DNA molecules. Its spelling is based on the four nucleotides that make up the DNA code: guanine, cytosine, adenine, and thymine. Each letter in GGTAC represents one of these nucleotides. The IPA phonetic transcription for this word would be /dʒi:ʤi:ti:ei:/. Understanding the spelling of DNA sequences is crucial in genetic research, as it allows scientists to accurately analyze and manipulate genetic material.