Normal human cells contain two copies of each gene – one inherited from a mother, and one from a father. An international collaboration of scientists including NYSCF Senior Research Fellow and NYSCF – Robertson Investigator Dr. Dieter Egli created human stem cells, cells that can mature into any type of cell in the body, with only one copy of each gene. These cells are known as ‘haploid’ cells since they maintain only one set of the genome, half, as opposed to the normal two sets. The research, published in Nature, represents a landmark in research techniques and biotechnology. These haploid stem cells mark the first time scientists created cells that can grow and divide infinitely with only one copy of the human genome.
For scientists, this unprecedented achievement will accelerate the pace of biomedical research and potential cell-based therapies. Typically, two copies of a gene means that cells have two chances to get it right, make a protein that functions correctly. However, on rare occasions both copies of a gene are faulty which can lead to painful lifelong conditions. For example, individuals with sickle cell disease inherit two damaged copies of a protein in blood cells; likewise, those suffering from cystic fibrosis contain mutations in both of their genes for a protein that transports small molecules across cell membranes. Scientists making sense of gene functions and different diseases currently must manipulate genomes to try to remove both copies of their gene of interest. With haploid cells, researchers can readily cut out, engineer, or tweak the single gene copy, an invaluable tool for speeding up the process of discovery giving researchers the power to study more complex diseases like diabetes and Alzheimer’s which may involve multiple faulty genes.
Excitingly this study by researchers at The Hebrew University of Jerusalem, Columbia University Medical Center, and NYSCF establishes that despite only having one copy of the genome these cells can be coaxed into becoming cells of any type of the three germ layers in embryos. This means that not only can scientists maintain cells with half the normal amount of DNA in an undifferentiated, stem cell state, but that researchers can also transform these cells into any cell type of interest and readily manipulate the single-copy genome. Creating cell-based treatments, understanding disease and discovering what it means to be human is even easier with this NYSCF-enabled breakthrough.
(Image: A haploid cell with 23 chromosomes (left), and a diploid cell with 46 chromosomes (right). Credit: Gloryn Chia/Columbia University Medical Center)