The Foundation of Life

The foundation of life

Genes are the building blocks of living things and it’s what makes each and every one of us so unique

Our genes dictate who and what we are. They are the reason why you’re tan or fair, tall or short, or have blond or black hair. To understand what genes are, we need to know about chromosomes and DNA (deoxyribonucleic acid).

Genes are the foundation of DNA which are contained in chromosomes. An average human has 23 pairs of chromosomes which consists of many strands of DNA, made up of thousands of genes.

Building block of every living being

Genes are made up of a long combination of four nucleotide bases -chemicals- called adenine (A), cytosine (C), guanine (G), and T (thymine). Different combinations of ATCG give people different characteristics. For example, someone with the combination, AAACCGGGTTTTT may have blue eyes but someone with the combination AAACCGGTTTAA may have brown eyes. The last two letters -TT- and -AA- could mean the colour and the first ten letters means the eyes.

A gene is any part of the DNA (see Image 1) with a set of instructions in it that allows a cell to produce a specific product such as an enzyme that triggers a precise action within the cell.

DNA is contained in every cell in your body and every single person in the world has a unique DNA signature.

In the family

We inherit our genes from our parents which is why sometimes, you may inherit their hair texture, skin colour or even look a lot like them. However, sometimes, traits may skip a generation and affect the grandchildren.

This is caused by our alleles which are the different forms of a gene. For example, there are different forms of the gene that controls hair colour which makes it possible for there to be so many different hair colours.

We receive one allele for each gene from the mother and the other allele from the father. One allele is always dominant and the other is weak, also known as recessive. A dominant allele means that the physical trait it controls such as black hair, is usually expressed.

Thus, if a person inherits one allele for black hair and one allele for blond hair the dominant trait which is black hair will be expressed. However, if the person inherits both recessive alleles for blond hair, the individual will have blonde hair.

In addition to physical traits such as hair colour, we can also inherit diseases such as breast and ovarian cancer, thalassemia and even obesity from the previous generation.

Genetic codes may sometimes be altered or deleted which causes a genetic mutation. The genetic mutation causes a disruption in the protein synthesis within the cell which could lead to abnormalities in the person.

This is how genetic disorders such as Down syndrome, cystic fibrosis, and colour blindness manifest.

Gene mapping

Now that we know about genes and how they control how we look, function and also our risk of developing certain diseases, wouldn’t it be great if we were able to map out our genes in order to identify unwanted genes and perhaps swap them with others?

Currently, genetic testing of foetuses is only done if a doctor believes that the foetus may have a birth defect. This test looks for specific genetic mutations such as ones that cause Down syndrome. What if there’s a way to look at each and every gene in a person and see the ‘programming’ that makes someone who they are?

A genome is a living thing’s complete blueprint of genetic instructions. The Human Genome Project aims to determine this blueprint. The project also aims to identify and map all of the genes of the human genome.

The main reason behind mapping our genes is so that doctors will be able to provide a more personalised form of healthcare. However, issues such as terminating less than favourable pregnancies or making a designer baby with traits that the parents want may occur which is why gene mapping is a hotly debated topic.Up until now, not all the genes that make humans how they are, have been identified.

Although not all of our genes have been identified, certain markers such as having the BRCA1 gene has been found to increase a person’s risk of breast cancer in women and men. The discovery of the BRCA1 gene is mainly preventive for someone who is found to be a carrier of this gene. A person who has the mutated BRCA1 gene won’t necessarily develop breast cancer but the gene can be passed on to their children who may, in the future, develop breast cancer. The best way to detect breast cancer in the early stages is still via regular mammograms.

Gene therapy

Gene therapy is like a Trojan horse except it does good instead of wreak havoc. This form of therapy is still being heavily researched but it is where genes are inserted into a sick person’s cells to treat a hereditary disease.

Additionally, gene therapy is being researched as a way to treat cancer as well. Researchers aim to use gene therapy in two ways to treat cancer. One way is to enhance the healthy cell’s ability to fight off the cancer and the other is targeting the cancer cells and destroying them or stunting their growth.

Hopefully, research on genes and how we can manipulate them will be fruitful in the fight against inherited diseases and various forms of cancer.

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