Basic Medical Terminology for Genetics

Basic Medical Terminology for Genetics
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  • 0:01 Genetics
  • 0:54 Organiation of Our Genes
  • 2:30 Dominant and Recessive
  • 4:42 Genetic Mutations and…
  • 5:30 Lesson Summary
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Lesson Transcript
Instructor: Adrianne Baron

Adrianne has taught high school and college biology and has a master's degree in cancer biology.

We are going to discuss some of the terms that are frequently used in genetics. We will take a quick glance at genes and basic inheritance patterns. An overview of mutations and genetic disorders will also be covered in this lesson.


Have you given much thought to exactly what makes you, you? What caused you to have the color eyes and hair you have? What determined your facial features? Perhaps you are taller or shorter than you want and you want to know what made you that way. The answer is your genes!

Not the ones you wear, but the ones in your cells. Genes are individual, functional pieces of DNA. Let me guess, you aren't exactly sure what DNA is either, right? Well, DNA is the hereditary material that encodes the instructions needed to make everything in your body.

We have learned more about our bodies and how they function through genetics, which is the study of genes and heredity. There are scientists that study genetics, and they are known as geneticists. Let's look at some of what they have discovered for us during their studies.

Organization of Our Genes

We just mentioned that genes are the functional units of DNA. This means that they are the smallest unit of DNA that are able to carry out the functions of DNA. We would really be a mess if our genes were just floating randomly in our cells. Thank goodness they are actually organized very well. All those pieces of DNA are linked together on what are known as chromosomes. Our chromosomes are thread-like strands of DNA wrapped around proteins.

Almost all of your cells have a full set of chromosomes, which we refer to as the genome. As humans, our genome consists of 22 pairs of autosomal chromosomes plus 2 sex chromosomes, which gives us a total of 46 chromosomes. The cells in your body that have the full set of chromosomes are somatic cells, which are the cells that make up every part of your body, such as your bones, skin, muscles, and nerves.

There are other cells in your body that only have 22 autosomal chromosomes plus 1 sex chromosome, making a total of 23 chromosomes. These are gametes. Gamete cells, commonly referred to as sex cells, are used to pass genetic information on to children. The gamete cells in males are sperm, and in females they are ova.

When sperm and ova join together to create a fetus, they each contribute their half set of chromosomes. This results in a baby that has a full set of chromosomes. Babies have characteristics of both parents since they both contribute their genetic information through gametes.

Dominant and Recessive

People often want to know why they have certain characteristics that look more like one parent and other characteristics that look more like the other parent. The answer to this lies in what we call alleles, which are various versions of the same gene.

We all have an allele for every gene in our genome. Let's look at earlobes for an example of this. There is an allele for attached earlobes, and there is an allele for detached earlobes. Your parents both contributed an allele for the gene that determines this characteristic.

Now, what happens if each of your parents gives you a different allele for a particular gene? The characteristic you display will depend on which one is dominant and which one is recessive. A dominant allele only requires one copy in order for you to show it. On the other hand, a recessive allele requires two copies in order for you to show it.

Let's revisit our earlobe example again. Let's say that your mom gave you the allele for detached earlobes and your dad gave you the allele for attached earlobes. You will have detached earlobes because that is the dominant allele. Either parent has an equal chance of giving you the dominant or the recessive allele for every gene in our bodies.

There is one exception to this rule and it applies to the sex chromosomes. There are two sex chromosomes, X and Y. Fetuses that receive an X from mom and a Y from dad are born male, while females receive an X from mom and another X from dad.

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