Every year on April 25th, International DNA Day is celebrated — a holiday established in 2003 in the United States to commemorate both the publication of the model of the DNA double helix structure (on April 25th, 1953) and the completion of the Human Genome Project (2003).
The discovery of the DNA double helix revolutionized biological and medical sciences. It led to the formulation of the central dogma of molecular biology, describing the flow of genetic information from DNA to RNA to protein (DNA-RNA-Protein).

Two helically twisted strands
Are composed of four types of nucleotides.
They contain deoxyribose, which is a pentose,
Connected with a phosphate group
And a ring-shaped nitrogenous base.
By hydrogen bonds,
Pyrimidines with purines
Are joined: adenine – thymine, cytosine – guanine.
A four-letter code,
A triplet code,
Carrying genetic information,
Corresponding to every organism.
Responsible for everything,
The core of molecular biology,
Explained in X-ray radiography—
By Franklin’s lens first brought to sight,
Then Watson, Crick, and Wilkins wrote it right.
A creation of remarkable nature,
Perfect in every part,
An object of study for chemists
And biologists,
It is an oracle and a hope,
Like a chain with its links,
So simple, yet so critical.

The reading of the full sequence of human DNA, consisting of more than 3 billion nucleotides (A, C, G, T), did not occur until 50 years after the discovery of the double helix structure. At the time, U.S. President Bill Clinton and U.K. Prime Minister Tony Blair declared:
“The human genome is without a doubt the most important, most wondrous map ever produced by humankind.”

In a paper by J. Watson and F. Crick, entitled A Structure for Deoxyribose Nucleic Acid, which appeared in the journal Nature and was only 1,000 words long, the key sentence was:
“It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.”

In 2025, we can also celebrate other anniversaries commemorating momentous discoveries in the history of molecular biology, including:

• The 100th anniversary of the discovery of 5-methylcytosine, the first modified base in DNA (1925),
• The 70th anniversary of the promulgation of the Central Dogma of Molecular Biology (1955),
• The 60th anniversary of the determination of the first alanine-specific tRNA nucleotide sequence (1965).

It is worth recalling that James Watson, Nobel Prize winner for the discovery of the structure of DNA, visited Poland at the invitation of Dr. Henryk Cioczek in 2008, meeting with scientists from, among others, the Polish Academy of Sciences. Pictured below is James Watson with Polish colleagues after a lecture at the Medical University of Lublin in 2008. (Photo: private archive of Prof. J. Barciszewski).

IBCH PAS contributes to the field of DNA chemistry and biology each year. Below are some of the publications dedicated to DNA research that were published between 2024 and 2025:

Julia Wieruszewska, Aleksandra Pawłowicz, Ewa Połomska, Karol Pasternak, Zofia Gdaniec, Witold Andrałojć, “The 8-17 DNAzyme can operate in a single active structure regardless of metal ion cofactor”, Nature Communications, 15, art. nr 4218, 2024. https://www.nature.com/articles/s41467-024-48638-x

Carolina Roxo, Anna Pasternak, “Switching off cancer – An overview of G-quadruplex and i-motif functional role in oncogene expression”, Bioorganic & Medicinal Chemistry Letters, 116, art. nr 130038, 2025. https://www.sciencedirect.com/science/article/pii/S0960894X24004402?via%3Dihub

Justyna Gołębiewska-Pikuła, Alva Abrahamsson, Erik Chorell, “Phosphate triester-based multifunctional handles for post-synthetic oligonucleotide functionalization”, Bioorganic Chemistry, 157, art. nr  108259, 2025. https://www.sciencedirect.com/science/article/pii/S0045206825001397?via%3Dihub

Paweł Śledziński, Mateusz Nowaczyk, Marianna Iga Śmiełowska, Marta Olejniczak, “CRISPR/Cas9-induced double-strand breaks in the huntingtin locus lead to CAG repeat contraction through DNA end resection and homology-mediated repair”, BMC Biology, 22, art. nr 282, 2024. https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-024-02079-6

Stanisław Trzciński, Jolanta Brzezińska, Krzysztof Waligórski, Joanna Strzelec, Katarzyna Kolet, Mateusz Klarek, Oskar Kołacki, Marcin K. Chmielewski, “Hybrid Supports for Oligonucleotide Synthesis: Controlled Pore Glass Derivatives with Branched Amine-Ended Polyether or Polyimine”, Chemistry-A European Journal doi.org/10.1002/chem.202403086

Rafał Nowak, Monika Gazecka, Markus Hoffmann, Ryszard Kierzek, Stefan Pöhlmann, Paweł Zmora,“TMPRSS2-specific antisense oligonucleotides inhibit host cell entry of emerging viruses”, Virology, 600, art. nr 110218, 2024. https://www.sciencedirect.com/science/article/pii/S0042682224002393?via%3Dihub

Barbara Mirska, Michał Zeńczak, Katarzyna Nowis, Ireneusz Stolarek, Jan Podkowiński, Magdalena Rakoczy, Małgorzata Marcinkowska-Swojak, Natalia Koralewska, Paweł Zmora, Elżbieta Lenartowicz Onyekaa, Marcin Osuch, Katarzyna Łasińska, Jadwiga Kuczma-Napierała, Marcelina Jaworska, Łukasz Madej, Marzena Ciechomska, Aleksander Jamsheer, Krzysztof Kurowski, Marek Figlerowicz, Luiza Handschuh, “The landscape of the COVID-19 pandemic in Poland emerging from epidemiological and genomic data”, Scientific Reports, 14, art. nr 14416, 2024.

https://www.nature.com/articles/s41598-024-65468-5