Chapter 1 - Introduction to Genetics


You’re watching Introduction to Genetics, chapter one of the genetics and fertility video series from the American Society for Reproductive Medicine.  

Genetics is the study of how traits and characteristics are passed from parents to their children. Genetic testing helps us understand who is at risk for passing on or receiving those traits. This video will talk about basic genetic biology, how traits are passed and inherited, and common types of genetic testing.

Let’s start with some basic terms.

Cells are the basic building block of all living things.

The basic parts of cells are:
  • Cell membrane—this is the outer wall of the cell that holds in all the other parts.
  • The cytoplasm is the area between the nucleus and cell membrane.
  • Cytoplasm contains mitochondria, which make energy for the cell.
  • The nucleus is the command center of the cell and holds the blueprints for how the cell functions.
  • Inside the nucleus are chromosomes which are made up of genes, which in turn are made up of deoxyribonucleic acid—better known as DNA. DNA is arranged in a specific sequence or order and it is this order that tells the cells how to function.
Now that we have the terms down, let’s talk about why genetics are important. Your traits are the things that make you—you. Traits are distinguishing characteristics of individuals like right-handedness, hair color or height. Most traits are passed from parents to children through the DNA in the genes that make up their chromosomes.

FUN FACT: Chromosomes come in pairs, you get one from each biological parent, 23 from your biological mother’s egg and 23 from your biological father’s sperm for a total of 46.
You can inherit more than just physical traits like hair color, you can also inherit a tendency towards a disease or mutated genes.

Wait what?

Mutated genes?

Mutations are changes in how the DNA is arranged in the gene represented here by the color purple (B). 

Everyone has some mutated genes and, a lot of the time, they don’t affect us in a negative way. Sometimes though, abnormal genes can show up as a serious medical condition, a genetic disorder, or cause a miscarriage.

Since we all have gene mutations, it’s often when two people with mutations in the same gene have children together that a problem occurs.

Before we talk about why a mutation might be important, let’s first talk about inheritance of mutations and disease: who gets what, and how.

We hope you found this information helpful. Go to the next chapter in this series.

For more information about genetic testing in the setting of infertility treatment please visit
is a patient education website of ASRM.