New Publications Weak spots in DNA: a shared origin for brain diversity and disease
Building a brain takes countless rounds of cell division, and every division has to faithfully copy three billion letters of our genetic code. Sometimes the copying machinery stalls, and the long string of DNA snaps. When the cell glues the broken ends back together in the wrong way, whole chunks of the genetic instructions go missing or get duplicated by accident — unplanned losses and gains the cell never scheduled. These changes are among the strongest known risk factors for autism and brain cancer. Yet why they keep happening at the same spots has remained a puzzle.
In a new study published in Nature Communications, the Wei lab at IZN and DKFZ identifies a fundamental source. Working with the stem cells that build the brain, the team focused on a handful of "weak spots" in the genetic code. These sit inside the longest genes used by brain cells — the very genes that help neurons connect and talk to each other — and they snap especially easily when DNA copying runs into trouble.
The Wei lab shows that these weak spots are the starting point for the unplanned losses. The breaking itself is predictable — it happens at the same spots every time DNA copying is stressed — but the repair is not: some cells heal cleanly, some lose the same chunk again and again, forming the recurrent changes seen in disease, and others patch the damage into large, one-of-a-kind rearrangements, leaving each neuron with a slightly different set of genetic building blocks. The same scheduled event is "bad luck" for cells whose repair goes wrong, and a source of natural diversity for the rest — a cell-to-cell variation now recognized as a normal feature of healthy brains, and a contributor to diseased ones. Strikingly, silencing the long genes shut down the breaks and the unplanned changes altogether.
The findings recast these weak spots as a central source of genetic diversity in the developing brain, opening new avenues for understanding how brain disorders and brain tumors begin.
Source:
Corazzi and Ing et al., Nature Communications (2026)
https://doi.org/10.1038/s41467-026-71790-5