A. Daily Blog
This chapter is all about the genetic research that scientists have compiled based on our genome. Scientists now have the ability to determine another organism's genome as well. Just to refresh your memory: what is a genome? A genome is the collection of ALL of your genes in your body. WAIT! What's a proteome then?? A proteome is the collection of genes that encode for a protein. As you may know, not all of your genes necessarily code for a protein/function. There is some variation in proteins which is what makes the proteome greater than the genome. The reason being is due to alternative splicing in eukaryotes and there are other forms of changing the protein such as phosphorylation, methylation, acetylation and etc. As we will learn in this chapter, some genes have "special functions" whereas some may "useless" (however this term is rejected by the scientific community). Let's talk about the genome of a general prokaryotic cell. Based on the previous chapters we know that the genetic material contained in cells such as Bacteria and Archaea are much less complicated than eukaryotic cells. However, some of these cells do have variations within them. Prokaryotic DNA is considered to be a few thousand base pairs long. It ranges from about 1,000-5,000 genes. Most prokaryotic DNA is in a circular shape unlike the helical shape that DNA takes the shape of in eukaryotes. There are a few examples of prokaryotes that don't follow the rule of having circular DNA.
Prokaryotes have only one origin of replication and lack introns. This is why we don't see any post modifications that occur to the mRNA that is transcribed by RNA Polymerase. Prokaryotes lack centromeres and telemores which make them more susceptible to cellular death. Most prokaryotic cells have a separate set of genetic material along with the circular DNA. Those are known as plasmids. Plasmids are self-replicating pieces of DNA and have protective functions for bacteria and also aid in binary fission (prokaryotic replication). Scientists use plasmids to mass produce certain genes. They generally have two main intentions for this: to examine specific proteins that are expressed or to use the proteins for different purposes. There are different kinds of plasmids that can be found in bacteria. There are col-plasmids (plasmids that are able to kill other bacteria), resistance plasmids (plasmids that have resistance against specific antibiotics), degradative plasmids (plasmids that have the ability to degrade material or digest them, virulence plasmids (plasmids that have the ability to turn bacteria into pathogenic strains) and fertility plasmids (give the bacteria the ability to come in contact and exchange genetic information). Let's move on to another topic that we covered that discusses a possibility in genetic variation.
Transposable elements are segments of DNA that move from one place to another. Many scientists are not sure exactly why these elements move segments of DNA. However, these elements have the ability to activate transposase which helps cut up the segments. Let's keep rolling! Bioinformatics is a big part of the genetics field. Scientists now have the ability to examine how DNA is sequenced and what the genes on these strands may code for. There are methods such as Dideoxy sequencing which allows scientists to determine what nucleotides are present where. There is also another popular method which helps separate DNA strands based on whether they express genes or not. This method is known as Mircroarray. The genetics field is still not complete but, we do have the materials to keep up with new information.
B. Useful Materials
Useful Video
| This is a very interesting video that I found that was made by college graduate students along with their professor. They explain the discovery of Transposable Element (TE) and how they may play a role in genetics. They mention the Selfish-DNA theory that is mentioned in the chapter. For all we may know, TE's may have purpose after all! |
Useful Link:
| The Human Genome Project |
| This is the link to the Human Genome Project as you can see! All this information is based off Bioinformatics. This link shows what tools, enzymes and properties were used in order to build the Human Genome Project. In class we discussed the ethical issues that this may cause. The link provides us with a better understanding of the general human genome. |
Useful Article:
| This is a pretty cool article where scientist want to study tumor tissue. In order to study these kinds of tissues, they need to be able to see the protein expression within the cell in order to determine what medications they can create in order to inhibit the cell growth. As you may know, scientists have to be able to separate the genome and proteome. They use a substance known as trizol which assist in the separation of certain biomolecules which helps determine what proteins are expressed. Very interesting! |