The researchers isolated different subpopulations of human brain stem cells and precisely identified, which genes are active in which cell type. In doing so, they noticed the gene ARHGAP11B: it is only found in humans and in our closest relatives, the Neanderthals and Denisova-Humans, but not in chimpanzees. This gene manages to trigger brain stem cells to form a bigger pool of stem cells. In that way, during brain development more neurons can arise and the cerebrum can expand. The cerebrum is responsible for cognitive functions like speaking and thinking.
The discovery of this genetic disorder, reported in two papers in the journal Cell, demonstrates the growing power of new tools to uncover the causes of diseases that previously stumped doctors.
Most siblings with a diagnosis of autism do not share the same genetic risk factors for the disorder and are as distinct in their behaviors as any brothers and sisters, scientists reported on Monday in a study that came as a surprise to many doctors, if not to parents.
Using a pre-drawn template can be helpful during a consultation to explain single gene inheritance. Our template shows one pair of chromosomes for each parent. Each chromosome has a single gene highlighted that can be coloured in to illustrate a gene alteration. You can then show which sperm and/or eggs contain the chromosome with the gene alteration and the different genetic combinations that could be present at conception.