PCR - Photocopying Genes

PCR is a common technique used to amplify specific regions of DNA. Put more simply, its a process that allows us to create copies of a piece of DNA. There are two main properties of PCR that we take advantage of - amplification (getting many copies) and isolation (of a single region).

If you understand the basic idea of photocopying, then you can understand PCR.

A short stretch of DNA that goes through 2 cycles of amplification ending up with 4 copies. I should note that the role of PCR has changed over time and I will mostly be focusing on the current use. Additionally, there are several …

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Gene Cloning: vectors, plasmids, ligations, and transformation - oh my!

The goal of gene cloning is to get a single copy of the gene from an animal and into an archive. The rest is just the individual steps necessary to do this. Cloning genes allows us to easily and consistently retrieve the exact same copy and to share it between labs or even organisms.

Step Description Biology Jargon
1     Get a copy of the gene from the animal PCR
2     Put the gene in an archival format Ligation into a plasmid
3     Make backup copies or archive it Bacterial transformation …
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Genes, Phenotypes and Traits

We are constantly seeing both news articles as well as scientific publications on new genes - the new gene for intelligence, cancer or happiness. So lets start at the beginning by figuring out what a gene is. Simply, its a way to refer to inherited traits.

When a gene is identified as playing a role in a trait, this can be caused by basically two things - 1) different versions of a gene called an allele or 2) changes in how or where a gene is used. To understand how genes can give rise to different traits, we need to first understand how a gene functions.

Thus, lets look at how, in the simplest case, a trait like the color of a flower, can arise from a gene.

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The basic but complex pieces of biology: DNA, RNA, & Proteins (aka Central Dogma)

All of biology functions around the core of DNA, RNA and Proteins or the so called Central Dogma of Molecular Biology. The key here is that you always go in the order of DNARNA→protein. You can’t jump from DNA to protein or visa versa; it just doesn’t happen. However, you don’t have to go all the way. Just because you made RNA doesn’t automatically mean it will be a protein. This is also not necessarily a one-to-one relationship. One RNA can be used to make several copies of the exact same protein.

Why do I care?

Because a gene can be looked at in each step of the DNARNA→protein progression. We look at all the different steps because how a gene is functioning can be regulated or changed at any point. However, in all cases, we are still interested in the gene.

Biological Levels are also explained through the analogy of a book.

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