What Is Genetics

The textbook definition of genetics tells us that it is a study of genes, the genetic information of organisms, heredity, and a couple of other things. It may sound a little overwhelming at first glance, but only unpacking each concept will make it easy to understand the basics of genetics. Before the beginning of modern scientific research, humans have used principles of inheritance in many ways, without knowing the processes behind the results they were getting. The study began in the 19th century, and today it is one of the most promising and fastest developing branches in the world.

Genetics is a study of inheritance and aligned processes.
Genetics is a study of inheritance and aligned processes.

Although it may seem like biology dominates the world of genetics, it is an interdisciplinary science combining elements from biology, chemistry, and physics. It is also essential for understanding how life functions both on a level of a population and an individual. Understanding basic principles in genetics will help you understand the world around us and yourself a lot better. Let’s take a look at the most basic concepts of genetics.

DNA – The CEO of The Cell

What is DNA?

You probably heard the phrase “it is in someone’s DNA” a few times in your life, but what really is DNA? Biologically speaking is a kind of molecule with a specific structure containing coded information about an organism. We can call DNA the CEO of the cell because the information it carries involves directions for every single process that goes in a cell. It specifies what should be done, how, where, when does it start and end. That means it contains data about the entire life of the cell, including its natural death. Because every living organism is built of cells (or is a single cell), we can say that DNA directs everything in our bodies.

DNA contains information about everything that goes on in our bodies. genetics
DNA contains information about everything that goes on in our bodies.

Processes in the cell

But how can one molecule direct everything in a cell at once? DNA carries coded information about specific processes. The piece of information needed for a particular task can be duplicated, transported where required, and translated into a molecule specific to the task. To simplify, we can think of it as a series of recipes written in a secret code. When we need one of the recipes, we rewrite it, and then we can bring it to the translator. The translator turns the code into a chain of simple ingredients. Afterward, the chain is formulated into what we need it to be and transport. Then, it completes its task for as long as specified in the recipe.

As you can see, while DNA issues an order, there is entire machinery that executes it. Every second, in every one of our cells, a lot of processes happen simultaneously because each cell (with a few exceptions) within the human body contains the same molecule of DNA, unique for each person. We established that only certain pieces of DNA are translated, but how is entire genetic information packed into every cell?

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Packing DNA in a Cell- Chromosomes

If we unfolded DNA from a single cell, we would get a 2m long molecule. If we then decided to unfold DNA from all our cells and stretch it, it would go to Jupiter and back ten times. Therefore, DNA in our cells is extremely well-folded. To achieve this condensation level, a piece of DNA is folded and winded multiple times into chromosomes. Thus, a chromosome is nothing but a highly well-folded piece of our genetic information.

Most humans have a total of 46 chromosomes, divided into 23 pairs (A gain or loss in the number of chromosomes from the normal 46 is called aneuploidy). The collection of all chromosomes representative of a certain species is called a karyotype. Chromosomes are typically very condensed but can be slightly unfolded when a piece of genetic information is needed.

Chromosomes are a hyper-condensed form of DNA packed into the nucleus of a cell. Genetics
Chromosomes are a hyper-condensed form of DNA packed into the nucleus of a cell.

Genes and Genomes

A gene is a fragment of DNA necessary for making one molecule. That involves the recipe itself and additional instructions that are cut off during the process of translating. A genome is a collection of all genes in the organism. Therefore, if we determine the DNA sequence (the code) in the entire genome, we can tell what instructions are in there, which will give us a lot of information about the organism whose genome we studied. This process is called whole genome sequencing (WGS), and it has numerous applications in the scientific world.

Genetics research involves genome sequencing.
Genome sequencing teaches us about human genetics.

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