Genetics: Easy as ABC

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...