neuroDEVELOPMENTS

Mosaics in mind

Studies find that not all neural genomes are alike

For this issue of neuroDEVELOPMENTS we focus on the startling reality of the mosaic nature of genomes in the human brain. Since the meeting of Craig Venter, Francis Collins, and Bill Clinton at the White House on June 6, 2000 to announce the first draft of the human genome, the idea that we all carry our own version of the human genetic code is commonplace. It is now clear that this is a simplified view of reality because every cell in our body does not have precisely the same genome. In fact, recent progress maps the remarkable extent and timing of DNA sequence change in the developing human forebrain. As a consequence, the genome of one neuron is not always the same as its neighbor’s. Here we introduce this idea with two recent DNA sequencing studies that show mutational mechanisms acting early in neurogenesis generate neuronal diversity in normal development and disease. The perspectives presented by the neuroDEVELOPMENTS board further emphasize the growing excitement in understanding better how many mutant neural stem cell lineages are first formed and then function together in our chimeric brains.

-Ron McKay, PhD, Chief Editor
Lieber Institute for Brain Development

-Venkata S. Mattay, MD
Managing Editor

-Michele Solis, PhD
Science Writer