About genetics

You might think genetics is a really complicated subject, or that it doesn’t have anything to do with you unless you’ve got a genetic disorder.  But our genes are literally what make us who we are.  And we’re going to show you that they’re absolutely fascinating!

Picture used with permission from the National Institute of General Medical Sciences.

Let’s start with the basics 

Our bodies are made up of approximately 50 trillion cells---that’s 50 million million!  Human cells contain nuclei which control the functioning of the cell.

Our genetic material (DNA) lives within the confines of the nuclei. Chromosomes are long strands of DNA, and it’s on these strands at a particular point that a specific gene is found. 

The majority of cells in the body carry 46 chromosomes, normally arranged in pairs. The only cells which have just one set of 23 individual chromosomes are the mature egg and sperm cells.

We inherit one set of 23 chromosomes from our mother’s egg and another set of 23 from our father’s sperm. They combine at fertilisation to give the first cell of an embryo a complete set of 46 chromosomes.

Our genes are the 'instructions' that tell our bodies how to grow and determine what we’re going to look like.  But when one of these instructions is missing or is faulty, it can cause a genetic disorder or a birth defect. 

For example, babies can be born with an Atrial Septal Defect (ASD) or a 'hole in the heart'.  ASD’s are caused by genes that were not working properly while the child was developing in the womb.  They didn’t give the body the right instructions and as a result, one of the walls in the heart didn’t completely form, leaving a “hole.”  Luckily, the majority of these cases are easy to treat with surgery.

Finding the problems – and solving them!

There are more than 4,000 recognised genetic disorders.  Scientists have only identified the genes responsible for about 1,000 of these and many disorders have no treatment or cure.

With an estimated 20,000-25,000 genes in our bodies, you can see why so much research is needed to find the causes of genetic disorders, and why your donations to Jeans for Genes are so important.

A lot of research is being done to investigate potential cures using bone marrow transplants and gene therapy.  Bone marrow is the soft, jelly-like tissue that’s found in the hollow centres of certain bones.  It's the home of what are called 'stem cells' which are the building blocks of blood. 

Stem cells, unlike all other cells in the body can eventually become any number of different cells. They may become red cells which carry oxygen, white cells which fight infection, or platelets which stop bleeding.

Immune deficiencies like Wiskott Aldrich Syndrome happen because the bone marrow doesn’t produce white blood cells or the cells don’t work.  New bone marrow from a donor will begin producing healthy blood cells and give children working immune systems, effectively curing their condition. 

But a transplant like this is a very invasive operation and children have to take anti-rejection drugs to help their bodies accept the new bone marrow.

Gene therapy

One of the most exciting treatments that’s being developed to treat a range of genetic disorders is gene therapy.  Funding from Jeans for Genes has helped scientists at Great Ormond Street's Institute of Child Health to start this ground-breaking project.

There are several genetic disorders that largely affected boys.  These are known as X-linked diseases and include conditions such as haemophilia.  Gene therapy was initially developed to treat an immune deficiency called X-linked severe combined immune deficiency or X-SCID.  This condition is often called ‘baby in the bubble’ syndrome because the children are so vulnerable to infection that they have to live in a sterile environment.

Gene therapy involves taking stem cells from a child’s bone marrow and identifying the ones which should have been fighting infections.  The defective gene in those stem cells, which means they’re not working, is replaced by a working copy.  The cells are then put back into the child’s bone marrow.  They generate new, fully working blood cells which restore the child’s natural defences against infection.

Ten children with X-SCID have benefited from the initial trial of gene therapy but much more research is needed to see if this same technique can be used to treat other conditions. 

This is an enormous leap forward for modern medicine and it wouldn’t have happened without your support.  By continuing to raise money for Jeans for Genes, you will speed up the development of these pioneering new therapies.

If you’re a teacher and you’d like more information about genetics, register for Jeans for Genes Day and you’ll receive a fundraising pack along with an educational pack based on the National Curriculum. You can also download materials to use in lessons and assemblies.

Tearless onions, inherited magic, and Genghis Khan in your family tree…it’s all down to genes!

The study of our genes is central to our understanding of practically everything about us.  And why onions make us cry, how you can get a blue robin and if Harry Potter inherited his magic abilities!  Visit our newsroom to read the very latest fun and fascinating stories from the world of genetics.