Scientists from Sanford Burnham Prebys Medical Discovery Institute, in collaboration with researchers in Hong Kong, have published a study in Genome Biology proposing a "potato model" of chromatin three-dimensional structure. This model offers a new perspective for understanding the relationship between the spatial organization of the genome and gene regulation. The discovery helps explain the molecular mechanisms underlying developmental disorders and cancers.

Using high-resolution imaging, the research team found that chromatin forms irregular, potato-like spherical structures within the cell nucleus. In these three-dimensional structures known as topologically associating domains (TADs), genomic regions located on the surface are more accessible to regulatory factors and exhibit higher activity, while regions buried deep in the core remain relatively silent. Lead author Dr. Kelly Yichen Li stated: "The 'coreness' metric we developed can precisely locate a gene's spatial position within the chromatin mass, and this correlates strongly with its expression level."

The study revealed that 12% of genomic abnormalities in breast cancer cells are associated with disrupted chromatin structure. Senior author Dr. Yuk-Lap Yip likened it to this: "Just as a potato skin protects the starch inside, the three-dimensional packaging of chromatin determines whether a gene can be 'reached' by regulatory signals." The quantitative method developed by the team can be applied to various cell types, providing a new tool for studying muscle stem cell differentiation and conditions such as muscular dystrophy.