Genetics: Easy as ABC

When we talk about our genome, we are referring to all the genetic material in our bodies, and we hold a copy of our genome in almost every healthy cell in our body; to give you an idea of how much DNA that is…if we were to uncoil all the DNA in one human body, it could stretch from the earth to the sun 600 times! Mind blowing, eh?! DNA or Deoxyribonucleic Acid is the chemical found in the cells of plants and animals that carries genetic information. DNA is made up of four base chemicals: Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). Humans typically have 46 chromosomes which are arranged in pairs with 23 chromosomes inherited from your mother, and 23 chromosomes from your father. Each chromosome in the pair has the same set of genes which correspond to one another. However, there may be one or more forms of these genes, known as alleles. Therefore, whilst we all have blood, we have different blood types. And maybe a bit gross, whilst we typically have earwax, someone’s ear...

What do you think of when someone says ‘Mutation’? The X-men? A zombie apocalypse? In reality, a mutation is simply a naturally occurring, random change in a gene. These mutations often have no effect, but occasionally, they can be harmful; for example, they could increase a person’s risk of developing cancer, a genetic disorder, and other rare diseases. However, scientists can detect these gene changes through genetic testing. There are several types of genetic testing, and they can be used to test individuals at different life stages: pre-natal testing detects harmful mutations in a foetus before birth; childhood testing is usually used to confirm a medical diagnosis or predict whether a disorder may develop and therefore requires observation. Any mutations detected during pre-natal and childhood testing are usually due to an inherited genetic mutation; conversely, adult genetic testing is used to predict late-onset genetic disorders, usually caused by mutations that occur in that ...

Widya Mulyasasmita, a geneticist from Stanford University, says that every living organism has a ‘recipe book’ which gives instruction on how to build it. In humans, this recipe book is split into 46 chapters, known as chromosomes. In each of these chapters, there are recipes for eye colour, how to make fingers, and how to build a brain; each of these chapters has a near identical partner chapter, one where the content is inherited from your father and the other from your mother. The important chapters, when it comes to determining whether you will be biologically female or male, are chapters 45 and 46, known as the sex chromosomes. There are two types of sex chromosomes: X and Y. Biological females have two X chromosomes (XX), and biological males have one X chromosome and one Y chromosome (XY). As the mother can only pass on an X chromosome, it is therefore the father who determines the child’s sex, as the dad can either pass on an X chromosome (which would make the resultant child...

In some cases, when carrying out scientific research, you cannot perform early investigations on humans due to ethical reasons. Therefore, to observe the impact of investigations in a real-world setting, rather than relying on theoretical or clinical research alone, we need a substitute to take the place of humans. For example, we could take a strain of Covid-19 and spray a bunch of bleach on it in a lab. Congratulations, we now have a potential way of killing Covid-19, let’s now just inject bleach into people to have the same result…not such a great idea (right Trump?). Ultimately, understanding scientific concepts and solving them in a clinical, theoretical setting, does not always translate into real-world solutions. Animals allow a kind of ‘intermediate’ to suggest how humans might respond, and thus have been vital in helping us understand human phenomena. But why do animals make the perfect ‘intermediate’? Widya Mulyasasmita, a geneticist from Stanford University, had a very cle...

Love them or hate them, royal families have a fascinating history. From the Egyptian Pharaohs to Queen Elizabeth II, there have been many monarchs across many continents and many years. Historically, one family would manage to stay in power through consanguinity, marrying a biological relative. The theory was that marrying a relative would keep the bloodline pure; ironically this led to the development of many genetic disorders in these families. To understand this, we must first understand how genetic conditions are inherited. A typical person has 23 pairs of chromosomes (46 in total, if you’re good at maths😉); you inherit 23 chromosomes from your mum, and 23 chromosomes from your Dad. In each of these pairs of chromosomes, you have genes, which correspond to one another. For example, one pair of chromosomes will hold the genes that define eye colour, so one chromosome includes the eye colour gene from the mother, let’s say it’s blue in this case, and the other chromosome include...

Imagine if we lived in a world where scientists could make drugs specifically tailored to your individual needs. Well, what was once only seen in sci-fi films, is now a reality. Pharmacogenomics combines pharmacology: the study of drugs, with genomics: the study of a people’s genes. This revolutionary new branch of science has the potential to develop drugs, specially tailored to an individual’s genetics; this would avoid negative side effects and perfect the dosage required for optimum effect. Pharmacogenomic s is a vital new field, less than 20 years old. Current drugs are based on a ‘one size fits all’ basis, but this does not necessarily mean they will work the same way for everyone. A person’s genetics may be the root cause of this difference, although other factors like gender, age, and lifestyle will all play their part. Professor Munir Pirmohamed said that most prescribed drugs only work in 30-50% of people. Furthermore, statistics show that 6.5% of hospital admissions in the...

In the wake of the Human Genome Project, which completed the sequencing of the entire human genome in 2003, the British Prime Minister in 2012 (David Cameron) announced the launch of the 100,000 Genome Project. This project took the Human Genome Project a step further, with the aim to sequence 100,000 genomes of patients with cancer and rare diseases. The project looked specifically at how the individuals’ genomes contribute to the development of disease, whilst also providing information which could improve disease diagnosis and personalised treatment. The project completed in 2018, and the findings were both vital and ground-breaking. To give some clarity on the hierarchy of what makes us, us, think about the image that we see when we talk about DNA: the spiralling ladder. Each of the ‘steps’ of the ladder are called bases and there are four different bases in DNA: Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). In total, there are around 3 billion bases in a person’s genom...