In this video, we're going to begin our introduction to microbial genetics. And so the term genome is a term that is referring to the complete set of genetic material in a cell. In other words, it's referring to all of the DNA within a living organism. And so this term genome is a term that you will hear several times as we move forward through our video lessons. Now organisms have the ability to transfer genetic information. And so, we refer to this as gene transfer. And this is really just the sharing of genetic information. And this can occur between microbes in two ways. The first way is by vertical gene transfer, and the second way is by horizontal gene transfer.
Now vertical gene transfer is going to be the transfer of genetic information between a parent cell and its offspring via replication. And so as a parent cell replicates and divides to create more cells, it will transfer genetic information from the parent cell to the offspring. And so if we take a look at our image down below on the left-hand side over here, notice we're showing you vertical gene transfer. And so notice that in vertical gene transfer the exchange of genetic material is going to be from parent to offspring. And so in this case here you can see that we've got an image here that says "This gene is for you, my son." And over here you can see the offspring is saying "Thanks, dad." And so the exchange of genetic material here, the DNA, is being transferred from parent to offspring and that is vertical gene transfer.
Now the second way that gene transfer can occur is through horizontal gene transfer. And this is going to be the transfer of genetic information between two organisms that are actually not direct descendants of one another. And so it's not going to be the transfer between parent and offspring. Instead, it's going to be like the transfer between two neighbors, two organisms that are not related by parent-offspring. And so here, notice in this image on the right, we're showing you an example of horizontal gene transfer. And so here what you can see is that the DNA or the genetic material is being exchanged between two individuals that are not related to each other parent to offspring. And so in this case, you can see on the left it's saying, "Hey, friend, I have this gene for you." And this cell over here is saying, "Thanks, buddy." And so you can see that the relationship between these two organisms is not parent-offspring. Instead, these two microbes could be completely different bacterial species, and they can exchange genetic material horizontally.
And so we'll get to talk more about horizontal gene transfer as we move forward through our course. But for now, this here concludes our introduction to vertical gene transfer. Now, one thing that is also important to note is that gene transfer only occurs in one direction. It only goes from the donor cell to the recipient cell. So, in this case, notice that the gene transfer is going from parent to offspring, but it doesn't go backwards. It goes only one direction. And the same thing in horizontal gene transfer, it's only going to go from the donor to the recipient in that direction during that one specific gene transfer event. And then, of course, this one could conduct horizontal gene transfer again, but again when in the single event of one horizontal gene transfer the genetic material is being transferred only in one direction from donor to recipient cell. And so this year concludes our brief introduction to microbial genetics, and so we'll be able to get some practice applying these concepts moving forward and learn more as well. So I'll see you on our next video.
