The human genome is enormous — some have likened it to the Bible in size — in which every letter stands for a gene.
You might be surprised to learn that some insects have millions of genes, and whales many more than
Much of the genome is junk, picked up over millions, perhaps a billion years or so, and has no obvious function. Of the rest, many work in concert with closely related genes, to turn other genes on (activate) or off (silence them). Without this essential function, differentiation of the fertilized ovum into the thousands of cells, which make up the body’s tissues and organs, such as the brain, would not be
The rest are protein-encoding genes, each one of which provides a blueprint for making proteins, each tasked with a very specific job. Most play key roles in structural components of the cell, while others may act as enzymes to facilitate a host of chemical reactions within the cell.
Some traits, such as height, are complex and depend on several hundred genes, which places the task of altering similarly complex traits well beyond current methods for editing the human genome. The same might be said for the multiple genes that influence so many risk factors for disorders such as hypertension.
There are, however, a host of protein-encoding diseases in which mutations affect a single gene. Many of these single gene diseases such as Huntington’s disease, which causes dementia in middle age; Duchenne muscular dystrophy, which leads to severe muscular weakness and death within the first three decades of life; and progressive muscular atrophy, which causes severe paralysis and death in infancy or within early childhood, are potentially fixable by employing gene-editing techniques or derivative RNA technologies to stop progression. In some cases, the disease can be prevented from developing in the first place. That’s very impressive.
Stem cells, the starter cells for mature cells, are a hot subject these days, especially in cancer, but also to repopulate the bone marrow with cells carrying healthy copies of mutant genes in patients with
diseases such as thalassemia and sickle cell anemia. Stem cells may also prove helpful in Parkinson’s disease by restoring functioning nerve cells in the brainstem.
The fertilized ovum is the mother of all stem cells, beyond which there are many other tissue-specific stem-cells such as those that live in the skin and bone marrow. In the case of the latter, they can create the whole gamut of red and white blood cells. Few stem cells exist in the brain, and of those that do, most are found in the temporal lobe in regions that serve memory. Unfortunately, however, there’s no evidence these stem cells play any useful role in preventing or slowing the memory loss in Alzheimer’s disease.
For more on these revolutionary subjects come to the InfoHealth session on Sept. 11, at 2 p.m. at the Niagara-on-the-Lake Public Library. The session will focus on gene editing and stem cell therapies. You may be surprised at how much progress has been made, even in some hitherto lethal neurological diseases.
Other fall InfoHealth programs include the Family Health Team, Part II, on Oct. 9, Artificial Intelligence in Health Care on Nov. 14 and Long-Term Care on Dec. 11, all starting at 2 p.m.