All living things grow and reproduce through the division of their cells. For this process to occur correctly and without complications, the cell must first copy and organise the genetic instructions found in the DNA precisely.

An important role in the transmission of information is played by the centromere, i.e. the central part of each chromosome, which consists of two chromatids that shrink there. The centromere, also known as the primary constriction, consists of highly repeated DNA, i.e. nucleotide sequences that repeat one after the other many times

In a study led by Simona Giunta from Sapienza’s Charles Darwin Department of Biology and Biotechnology, her group analysed this specific region of the chromosome, which had long been thought to consist of an obscure agglomeration of DNA. They discovered that each centromere actually carries a unique organisation specific to each chromosome. These results, published in the journal Science, enabled these complex sequences to be indexed, paving the way for precise comparisons between individuals and the occurrence of specific diseases.

"Using new sequencing technologies and computational algorithms, we were able to read these sequences for the first time," says Simona Giunta, professor at Sapienza University and director of the Giunta Lab. "We also discovered that each chromosome has its own unique pattern, like a barcode, which remains consistent when observed in different people."

In particular, the researchers discovered that the centromeric motif — a DNA sequence originally thought to be confined to the centromere — is also found outside of this region, distributed in a conserved and organised manner along the chromosome arms. Similar to synteny, which uses the position of genes along the chromosome, the specific organisation of this motif — termed 'centenia' by the researchers — can be used to generate chromosome-specific barcodes.

The human centeny map provides a fundamental tool for studying and comparing genomic structure at high resolution, including those regions - such as centromeres and other repetitive elements - that have so far remained largely excluded from classical genomic analyses.

“Just as one can scan a barcode to obtain information about a product, it will be possible in the future to scan centromere codes to understand their evolution and behaviour in specific pathologies,” says Luca Corda, the paper's first author and a PhD student in Genetics and Molecular Biology at Sapienza University.

The study is part of a larger project, supported by the Fondazione AIRC per la Ricerca sul Cancro and, more recently, by the European Research Council (ERC), aimed at investigating the role of centromeres in cancer and genetic diseases. Research in the field of genetics is undergoing a paradigm shift: we are no longer only interested in genes, but also in complex, repetitive regions of the genome - such as the centromeres - that have so far remained on the sidelines.

"These regions are finally becoming accessible, thanks to new tools, and raising new questions that will be the focus of future research," says Simona Giunta. "Understanding centromeres represents a new frontier in revealing previously unknown aspects of our genetic heritage."

References:

Luca Corda, Simona Giunta, Chromosome-specific centromeric patterns define the centeny map of the human genome. Science 389, ads3484 (2025). DOI:10.1126/science.ads3484

Further Information:

Simona Giunta

Department of Biology and Biotechnology "Charles Darwin"

simona.giunta@uniroma1.it