Lecture, chapter 9 - From genes to proteins

Today we continued covering chapter 9, on how the information stored in the genetic code gets reflected on a phenotype, specifically in proteins.

We talked about the processes of translation transcription, including the stages that each one has (initiation, elongation, and termination in both cases).

In the case of trascription we talked about the elements that are found in a gene, and how they get trnascribed into a pre-mRNA transcript, which gets modified into a mature mRNA transcript. We also discussed the different elements that make a mRNA molecule, including a 5' cap and a Poly-A tail.

In the case of translation we covered the cytoplasmatic elements that play a role in it: amino acids, ribosomes, and tRNA. We also discussed the chemical make up of amino acids, an amino, a carboxyl, and an 'R' groups, and a few of their characeristics.

On Monday: We'll finish chapter 9 and begin chapter 10.

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Lecture, chapters 8 and 9 - RNA, chromosome structure, and gene expression

Today we finished the chapter on DNA and chromosome structure. It should have been "nucleic acid and chromosome structure".

We discussed the primary and secondary structure of RNA, how DNA is coiled (and supercoiled) to from chromosomes, and then we started the next chapter in the text book, on how the information stored in DNA is used to form proteins.

Note: The draft papers on bioethical issues were returned with recommendations to improve what you have so far. Tomorrow I'll provide a handout with indications of how to cite and reference papers in a scientific fashion.

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Lab 06 - Mapping genes in Drosophila

http://www.drosophilab.com
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Although the actual lab will be a take-home lab, we set the stage to do the work we need to do in the couple of mapping genes labs we will have.

We covered concepts like gene mapping, genetic linkage, and genetic distance within a chromosome, and how they are correlated. We also introduced the concept of CentiMorgan (cM), a.k.a. Map Unit (m.u.), and how it is useful to map genes, based on the results of experimental crosses.

We also used a little applet developed by Paul Lewis, from the University of Connecticut, called demonstration of crossing over. With this application we did simulations on recombination events affecting two loci separated by variable genetic distances. We then introduced the concepts of parental haplotypes/gametes and recombinant haplotypes/gametes, as part of the more practical explanation of genetic linkage.

We also did a quick demo of the software to be used in this lab: DrosophiLab. Students will download this Windows-based free software to simulate experimental crosses in Drosophila melanogaster, and calculate genetic distances between different genes. The labguide is being written and will be posted soon.

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