Genes are the blueprint for our bodies. They dictate everything about the body, from the size and shape of our nose through to our ability to see in the dark.
Every cell in the body contains a copy of the blueprint. And this blueprint is made up of a sequence of 4 proteins called adenine (A), guanine (G), thymine (T), and cytosine (C).
Different patterns of A, G, T and C makes up a strand of DNA. Then, several strands of DNA twisted together (like a ladder) form something we call a chromosome. And several chromosomes form a gene.
Genes get shared across generations. Which is how children share characteristics of their parents. But just like anything in this world mistakes can happen.
For a crude example if A-A-C-T-G-A produces a normal healthy liver. A spelling mistake could occur with one letter missing or swapped it could mean a bad liver gets built.
You might have heard that heart problems or diabetes “run in the family.” Well, that’s because the genes hold these spelling mistakes, or aberrations and they move through the family line.
Joining Father and Mother Together
We have 46 paired chromosomes, and around 23,000 genes. The 46 chromosomes in the human cell are made up of 22 paired chromosomes. These are numbered from 1 to 22 according to size, with chromosome number 1 being the biggest. These numbered chromosomes are called autosomes. Cells in the body of a woman also contain two sex chromosomes called X chromosomes, in addition to the 44 autosomes. Body cells in men contain an X and a Y chromosome and 44 autosomes.
The 23,000 genes come in pairs. One gene in each pair is inherited from the person’s mother and the other from their father. A sperm and an egg each contain one copy of every gene needed to make up a person (one set of 23 chromosomes each). When the sperm fertilises the egg, two copies of each gene are present (46 chromosomes), and so a new life can begin.
Dominant and recessive genes
There are two copies of the genes contained in each set of chromosomes. These both send special messages to tell the cell how to work. Some of these genes are dominant over others.
For example, brown eye colour is a dominant gene. So when it’s paired with eye colour the most probable outcome is brown eyes.
Because gene sequences are complicated two parents with blue eyes could have a child with brown eyes.
As of today, we know that there are upwards of 1,700 gene related conditions. Some of these are as a direct result of aberration, and others are only indirect.
For example, it’s estimated that about 50% of Australians will be affected by a genetically related illness at some point in their life.
There are three ways in which genetic conditions arise:
- A variation in the gene that makes it bad (a mutation) that occurs randomly during the formation of the egg or sperm, or at conception.
- The faulty gene is passed from parent to child and may directly cause a problem that affects the child at birth or later in life.
- The faulty gene is passed from parent to child and may cause a genetic susceptibility. Environmental factors, such as diet and exposure to chemicals, combined with this susceptibility to triggering the onset of the disorder.
Early Problem Detection
Genetic counselling is available for people wanting a prenatal diagnosis to understand how existing parental conditions may affect a child.
Speak to your doctor today or Paediatrician and ask for a referral.
Jeans For Genes Day
Every year on the first Friday of August (which falls on the 2nd in 2019), Australians unite on Jeans for Genes Day by wearing their favourite jeans, donating money and purchasing merchandise to support genetic research.