To celebrate the start of the school year in the US, Google featured a Doodle highlighting DNA chemistry on Sept. 10, 2025.
The doodle itself features a rotating double helix; guanine, which is one of the four nucleotides that most commonly make up the code of DNA; and a phosphate molecule, which alternates with deoxyribose sugars to make up the backbone of DNA. An individual artist is not credited for the Doodle.
Early in the day, clicking on the Doodle would take a user to the Google search results for the search term “DNA,” the abbreviation for deoxyribonucleic acid. But at the time of publication, clicking on the doodle takes the user to Google’s artificial intelligence–powered search, AI Mode, prefilled with a prompt: “I remember DNA has A, T, C, and G… but who decides which ones go where? How does the sequence get set, and what happens if something goes out of order? What’s a memory device I can use on an upcoming test?” At the bottom of the AI response is a statement that says AI responses may include mistakes.
According to Google’s overview page for the doodle, searches for DNA peak annually during the school year. With the release of the DNA Google Doodle, searches of DNA today are at their peak over the past 5 years and near the all-time peak in the US, based on data from Google Trends, which began tracking search trends in 2004. Typically, searches for DNA peak around February each year and are not particularly high in September, according to that same data set.
Along with guanine (G), DNA contains the nucleotides adenine (A), cytosine (C), and thymine (T), which together typically form AT and GC pairs. But DNA can also sometimes contain the nucleotide uracil (U), more commonly found in place of thymine in RNA, when a mutation causes cytosine to lose its amine group (NH2). Similarly, inosine (I) is formed when adenosine, which is adenine attached to a ribose, loses its amine group. Guanine, the nucleotide pictured in the Doodle, lends itself to more than just a portion of our genetic code—thanks to its optical properties, it also gives sight to scallops and a disco ball–like shine to some spiders.
DNA is small, roughly 2 nm in diameter, but laid end to end, the sum total of DNA in a human cell would stretch for 2 m. Inside a human cell, DNA is organized into compact structures called chromosomes, pictured in the lower left of the doodle, during prophase in cell division. Otherwise, DNA is for the most part loosely organized in the nucleus of a cell. But DNA can also fold itself into much more complex shapes such that scientists have developed systems of DNA origami.
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