Genetics - Definition, History and Impact | Biology Dictionary (2023)

Genetics Definition

Genetics is the study of genes and inheritance in living organisms. This branch of science has a fascinating history, stretching from the 19th century when scientists began to study how organisms inherited traits from their parents, to the present day when we can read the “source code” of living things letter-by-letter.

Genetics started out with curiosity about why things are the way things are – why do children resemble one parent more than another? Why do some species resemble each other more closely than others?

It has evolved into an almost universal answer handbook for biology. By reading the “source code” or “blueprint” for an organism, scientists today are often able to pinpoint exactly where an organism came from, how it has changed over time, what diseases it might develop, and how its life processes are similar to or different from those of other organisms.

History of Genetics

In the 19th century, it was known that offspring resemble their parents – but almost nothing was known about why this happened. Why did some children “take after” one parent, but not the other. Why could plants and animals have offspring that had traits seen in neither parent? Why did some species resemble each other more closely than others?

In the 19th century, Gregor Mendel began examining inheritance in a systematic way by breeding pea plants. He tracked several traits of pea plants across several generations, recording what kinds of parents had what kinds off offspring. He successfully derived the mathematics behind dominant and recessive genes – the first empirical evidence that traits really were passed down in some measurable way from parent to offspring.

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The image below shows a Punnett square of Mendel’s pea plants. The Punnett square was developed by English geneticist Reginald Punnett to visually represent how dominant and recessive traits were passed to offspring. The math yielded by the Punnett square matched the results Mendel found in his hands-on studies of pea plants.

Around the same time, Charles Darwin was writing “The Origin of Species,” after examining changes in the traits if island finches during times of drought and plenty. Darwin concluded that finches which had the traits best-suited for survival were most likely to survive to pass those traits on, yielding changes in the traits of the overall population over time.

His work, when taken together with Mendel’s, began to suggest that all species on Earth might be related to each other, and might have gradually drifted apart by inheriting different traits through natural selection.

From there, the field of genetics advanced slowly. By the early 20th century, scientists using light microscopes powerful enough to see into a cell’s nucleus suspected that chromosomes were the seat of genetic information. They were able to connect chromosomal inheritance to trait inheritance, proving that the “instructions” for inherited traits were carried on chromosomes within the nucleus of eukaryotic cells.

The next great break in genetics started in the late 20th century, when the technology to read the nucleotide “source code” of the genome began to become available. Since then, the technology has gotten faster, more affordable, and more accurate – allowing scientists to sequence the whole genomes of many organisms and compare them.

(Video) DNA, Chromosomes, Genes, and Traits: An Intro to Heredity

Impact of Genetics

The ability to read the “source code of life” has led to a revolution in the way we think about and classify organisms.

Prior to the advent of gene sequencing, scientists guessed at organisms’ relationships to each other by studying their physical characteristics. Organisms with similar characteristics were often assumed to be related – even though many examples were known of convergent evolution, where two unrelated organisms evolve the same traits separately.

With the advent of gene sequencing and molecular genetics- referring to the ability to read the DNA molecule at the molecular level- it became possible to trace descent lineages directly. Scientists can now read a cell’s source code and determine at where, and roughly when, an organism’s genome changed.

As a result, a great deal of material that was taught in schools as recently as ten years ago is now known to be incomplete. Archaea and bacteria – once classified in the same kingdom – are now known to be genetically quite different from each other. Fungi are now known to be more closely related to animals than plants. Many other fantastically weird and fascinating discoveries have come out of the genome revolution – each one bringing us a step closer to understanding what makes us who we are, and how we are interconnected.

Gene sequencing has also led to a revolution in the way we think about, diagnose, and treat disease. In many cases, it’s now possible to know how likely a person is to get a given disease based on looking at their genome.

Scientists hope that this will lead to great revolutions in medicine in the centuries to come – as medicine catches up to genetics, it may someday be possible to determine what medications will work best on a disease, or what lifestyle changes will keep a person healthy, simply by reading their DNA.

This has also led to new ethical and economic challenges.

(Video) Definition and History of Genetics

Some women whose genes have certain mutation of the BRCA1/2 gene, for example, opt to have their breasts and ovaries removed even if they are healthy – because they know there is a high chance that they will develop cancer in these organs.

In 2013, Angelina Jolie made headlines by going public with her choice to have her own breasts removed after finding out through a genetic test that she had an 87% chance of some day acquiring breast cancer.

In other cases, geneticists can tell people that they will develop a serious disease – but do not yet have the tools to stop it from happening. People in families with Huntington’s disease, for example, can find out if they have the gene for this devastating and inevitably fatal dementia. But what can they do with this information?

An unexpected economic challenge has come from health insurance companies. Insurance companies have always made their money by gambling on who was likely to get sick and who wasn’t. Now that the tools exist for companies to find out who is more likely to get sick at a very fine level of detail, concerns have been raised that people with unhealthy genes might be charged much more for health insurance than people with healthy genes.


1. Which of the following was NOT known when Gregor Mendel began his studies?
A. That offspring tended to resemble their parents
B. That parents sometimes had offspring who didn’t look like either of them
C. That some traits are dominant and some are recessive
D. None of the above

Answer to Question #1

(Video) Definition of genetics

C is correct. Mendel developed the theory of dominant and recessive genes after carefully studying the pattern of inheritance of traits among pea plants over several generations.

2. Which of the following was NOT a reason for misclassifying many organisms prior to the advent of molecular genetics?
A. The organisms looked similar under the microscope
B. The organisms had evolved similar traits
C. Scientists were unable to read the organisms’ “source codes” and had to work off of superficial characteristics
D. Scientists of the past were less intelligent than scientists of today

Answer to Question #2

D is correct. Scientists of the past were incredibly innovative, designing experiments that yielded brilliant insights with very limited tools. But without the ability to read an organisms’ genetic code, they were restricted to making guesses about how to classify organisms based on their superficial characteristics.

3. Which of the following is NOT a possibility as genetic science advances?
A. It may become possible to replace unhealthy genes with healthy genes, if a safe genetic engineering vector for humans is developed.
B. It may become possible to choose the best medication for a disease right away based on the disease’s genetic profile.
C. Laws may need to be passed ensuring that people with genes for certain illnesses are protected from discrimination and have access to healthcare.
D. None of the above.

Answer to Question #3

D is correct. All of these are possibilities for the next century, as scientists continue to learn more about genes and how to work with them!

(Video) Genetics Basics | Chromosomes, Genes, DNA and Traits | Don't Memorise


  • Darwin, C. (1902). Origin of species. New York: American Home Library Company.
  • Toomey, A. (2013, August 16). Angelina Jolie’s Doctor Talks Actress’ Double Mastectomy. Retrieved April 29, 2017, from


What does genetics mean in history? ›

Genetics arose out of the identification of genes, the fundamental units responsible for heredity. Genetics may be defined as the study of genes at all levels, including the ways in which they act in the cell and the ways in which they are transmitted from parents to offspring.

What is the impact of genetics? ›

Understanding genetic factors and genetic disorders is important in learning more about promoting health and preventing disease. Some genetic changes have been associated with an increased risk of having a child with a birth defect or developmental disability or developing diseases such as cancer or heart disease.

What are genetics easy definition? ›

​​​What is genetics? Genetics is the scientific study of genes and heredity—of how certain qualities or traits are passed from parents to offspring as a result of changes in DNA sequence. A gene is a segment of DNA that contains instructions for building one or more molecules that help the body work.

What are the significant events in the history of genetics? ›

Genetics: Timeline of key events
1 Oct 1744Jean-Baptiste Lamarck was born in Bazentin, Picardy, FranceGenetics
5 Apr 1804Matthias J Schleiden was bornCell, Genetics
16 Feb 1822Francis Galton was born in Birmingham, UKGenetics
20 Jul 1822Gregor Johann Mendel was born in Hyncice, Czech RepublicGenetics
8 more rows

What is the definition of genetics quizlet? ›

genetics. The scientific study of heredity. fertilization. The process in which an egg and sperm cell join to form a new organism.

What is genetics and why is it important to study? ›

Genetics is the study of heredity at multiple levels of understanding, ranging from molecules to populations. Genetics occupies a central position in modern biology, so its understanding is essential for all scholars of the life sciences. The discipline has great impact on many everyday aspects of human life.

What is the impact of genetics in the society? ›

People's genetic information is increasingly being used for a wide range of non-clinical purposes, such as solving crimes, determining paternity, and exploring one's ancestry.

What impact has the study of genetics had on our society? ›

We can now analyze a person's genetic data and use that information to help guide care and therapy, identify disease risk, develop customized treatments and more. Additionally, individuals can use that information to make more informed decisions and take control of their health.

What is the impact of genetics in your family? ›

Our genes carry information that gets passed from one generation to the next. For example, genes are why one child has blonde hair like their mother, while their sibling has brown hair like their father. Genes also determine why some illnesses run in families and whether babies will be male or female.

What is genetics answer in one sentence? ›

Genetics is the study of how genes and how traits are passed down from one generation to the next.

What is genetics and example? ›

Genetics is the study of genes. Our genes carry information that gets passed from one generation to the next. For example, genes are why one child has blonde hair like their mother, while their sibling has brown hair like their father.

When did genetics start? ›

The scientific history of genetics began with the works of Gregor Mendel in the mid-19th century. Prior to Mendel, genetics was primarily theoretical whilst, after Mendel, the science of genetics was broadened to include experimental genetics.

What is the most important function of genetic? ›

Why are genes so important? Genes are the building blocks of life. They contain information for making specific molecules and proteins that allow human cells to function and that control how the body grows and operates.

What are 3 interesting facts about genetics? ›

Interesting Facts about Genetics

Humans share about 90% of genetic material with mice and 98% with chimpanzees. Nearly every cell in the human body contains a complete copy of the human genome. We get 23 chromosomes from our mother and 23 from our father. Some diseases are inherited through genes.

What are the advantages of genetics as a source of history? ›

Our experience suggests, then, that the biological sciences can be usefully deployed to inform historical analysis. Molecular genetics has the power to reconstruct a history of material existence—in this case, of microbes—at a level that no other kind of historical source or method can reach.

What is genetics in the Oxford dictionary? ›

/dʒəˈnetɪks/ [uncountable] ​the scientific study of the ways in which different characteristics are passed from each generation of living things to the nextTopics Biologyb2. Oxford Collocations Dictionary.

What is genetics kid friendly definition? ›

Genetics is the study of the way physical traits and characteristics get passed down from one generation to the next. This is also called heredity. Genetics includes the study of genes, which have a special code called DNA that determines what you will look like and whether you are likely to have certain illnesses.

What is genetics introduction? ›

Genetics is the study of how genes bring about characteristics, or traits, in living things and how those characteristics are inherited. Genes are specific sequences of nucleotides that code for particular proteins.

How does genetics affect your daily lives? ›

Genes are the instructions for life as we know it. They affect your development before you're even born and play a role in everything from your appearance to your personality. Genes contain information about your heritage and your risk for certain diseases.

How are the concepts of genetics applied in real life? ›

Scientific research has today advanced further and identified genes coding for the way muscles in our body respond to diet and training, skin types and their response to nutrition, the control of hair fall, risk of diabetic complications, obesity, addictions and a lot more. “This actually came to us from the public.

What are the factors that affects genetics? ›

Similarly, drugs, chemicals, temperature, and light are among the external environmental factors that can determine which genes are turned on and off, thereby influencing the way an organism develops and functions.

How do genetic factors affect public health? ›

Risks for almost all human diseases result from the interactions between inherited gene variants and environmental factors, including chemical, physical, and infectious agents and behavioral or nutritional factors, raising the possibility of targeting disease prevention and health promotion efforts to individuals at ...

How much do our genetics impact us and our behavior? ›

Genes typically account for no more than one-half to two-thirds of the variation seen in most individual's psychological traits. But most environmental influences are based on individual experiences and exposures that are not shared by family members.

What is the impact of genetic testing? ›

Generally genetic tests have little physical risk. Blood and cheek swab tests have almost no risk. However, prenatal testing such as amniocentesis or chorionic villus sampling has a small risk of pregnancy loss (miscarriage). Genetic testing can have emotional, social and financial risks as well.

How does genetic research help human kind? ›

Genetic research is the study of human DNA to find out what genes and environmental factors contribute to diseases. If we find out what causes disease, we can better detect disease, better treat disease and hopefully even prevent disease from happening in the first place!

How does genetics impact the process of development? ›

​As we all know, the inherited genes from our parents influence everything from height, eyes colour, hair colour and other physical characteristics, to intelligence, behavioural patterns and personality traits. Who we are today is shaped by our genetic background as well as environmental influences.

What is the impact of family? ›

Family relationships provide resources that can help an individual cope with stress, engage in healthier behaviors, and enhance self-esteem, leading to higher well-being.

What is the impact of family on society? ›

The family performs several essential functions for society. It socializes children, it provides emotional and practical support for its members, it helps regulate sexual activity and sexual reproduction, and it provides its members with a social identity.

Does family history mean genetics? ›

A family history can help determine whether someone has an increased genetic risk of having or developing certain diseases, disorders or conditions. It is often recorded by drawing a pedigree (a family tree) that illustrates the relationships among individuals.

What is family history in genetics? ›

Family health history is a record of the diseases and health conditions in your family. You and your family members share genes. You may also have behaviors in common, such as exercise habits and what you like to eat. You may live in the same area and come into contact with similar things in the environment.

What are the 3 types of genetics? ›

Genetic diseases can be categorized into three major groups: single-gene, chromosomal, and multifactorial.

Why is genetic important? ›

Genetics helps to explain: What makes you unique, or one of a kind. Why family members look alike. Why some diseases like diabetes or cancer run in families.

How does genetics and your family history impact your personal health? ›

A family health history can identify people with a higher-than-usual chance of having common disorders, such as heart disease, high blood pressure, stroke, certain cancers, and type 2 diabetes. These complex disorders are influenced by a combination of genetic factors, environmental conditions, and lifestyle choices.

Why is it important to understand family history and genetics? ›

A properly collected family history can: Identify whether a patient has a higher risk for a disease. Help the health care practitioner recommend treatments or other options to reduce a patient's risk of disease. Provide early warning signs of disease.

How is genetics used in everyday life? ›

Scientific research has today advanced further and identified genes coding for the way muscles in our body respond to diet and training, skin types and their response to nutrition, the control of hair fall, risk of diabetic complications, obesity, addictions and a lot more.

When was genetics discovered? ›

1866 - Gregor Mendel discovers the basic principles of genetics. In 1866, an unknown Augustinian monk was the first person to shed light on the way in which characteristics are passed down the generations. Today, he is widely considered to be the father of genetics.

Who discovered genetics? ›

In the 19th century, it was commonly believed that an organism's traits were passed on to offspring in a blend of characteristics 'donated' by each parent.

What is the importance of history taking? ›

Patient's history taking is one of the most important skills in medicine. Its is the key-stone to clinical diagnosis and doctor-patient relationship. 'The medical history' is a structured assessment conducted to generate a comprehensive picture of a patient's health and health problems.

How can mutation affect human life? ›

Genetic mutations are changes to your DNA sequence that happen during cell division when your cells make copies of themselves. Your DNA tells your body how to form and function. Genetic mutations could lead to genetic conditions like cancer, or they could help humans better adapt to their environment over time.

What are 5 examples of genetic factors? ›

What You Need to Know About 5 Most Common Genetic Disorders
  • Down Syndrome. ...
  • Thalassemia. ...
  • Cystic Fibrosis. ...
  • Tay-Sachs disease. ...
  • Sickle Cell Anemia. ...
  • Learn More. ...
  • Recommended. ...
  • Sources.

What are the 2 main types of genes? ›

There are two types of molecular genes: protein-coding genes and noncoding genes.

How many genes do humans have? ›

An international research effort called the Human Genome Project, which worked to determine the sequence of the human genome and identify the genes that it contains, estimated that humans have between 20,000 and 25,000 genes. Every person has two copies of each gene, one inherited from each parent.


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