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During long-term culture, human embryonic stem (hES) cells may acquire chromosomal abnormalities that compromise their potential clinical utility. A study of 17 hES cell lines reveals various genomic changes, including trisomies and monosomies, an amplification at 20q11.21 and a derivative chromosome 18.
During long-term culture, human embryonic stem (hES) cells may acquire chromosomal abnormalities that compromise their potential clinical utility. Lefort et al. show that an amplification at 20q11.21 arose at relatively late passage number in three of five hES cell lines.
Backbone fragments of the Agrobacterium tumor-inducing (Ti) plasmid that bears transgenes of interest have occasionally been reported to be transferred to plant genomes. Now, Ülker et al. show that Agrobacterium chromosomal DNA can also be integrated into transgenic plants at a low frequency. Gene-bearing chromosomal fragments as large as 18 kb are found in T-DNA–tagged populations of Arabidopsis thaliana.
Existing methods for reprogramming somatic cells to 'induced pluripotent stem cells' are inefficient, with only a small fraction of the starting cell population becoming pluripotent. Working with mouse embryonic fibroblasts, Hunagfu et al. increase reprogramming efficiency by treatment with DNA methyltransferase and histone deacetylase inhibitors.