High-fidelity human chromosome transfer and elimination - Science | AAAS

Whenever a cell divides, it has to split its chromosomes perfectly between two daughter cells, and even a single mistake can be disastrous. Now, researchers from Japan have found that one of the key structures that makes this possible takes a surprising shape: a hollow sphere.

Cancer may come with a trace beyond the tissue that looks cancerous. In men, that trace may be a missing Y chromosome in cells that still look perfectly normal, new research shows. That was the surprise in a study of tissue from men with and without cancer. Cells immediately beside tumors showed more Y chromosome loss than normal tissue from men without cancer, while the tumors showed even more. "What surprised us most was that Y chromosome loss was not confined to the cancer itself," Dan Theodorescu, director of the University of Arizona Cancer Center and senior author of the study, told ScienceAlert. Most cells in a man's body carry one X and one Y chromosome. Occasionally, when a cell divides, a descendant loses the Y. As those cells multiply, they form pockets of tissue in which some cells carry the chromosome and others do not. Researchers call this mosaic loss of Y. To find out where those pockets occur, Theodorescu and his colleagues examined 1,000 archived tissue samples from 405 males, covering 11 major organs. Their fluorescence in situ hybridization (FISH) test made X and Y chromosomes visible in more than 4.3 million cell nuclei.