Lecture, chapter 6 - Cytogenetics

A human karyotype
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Today we started chapter 6 on cytogenetics.

We covered karyotypes, chromosome nomenclature, and classification of variation in chromosome number: Polyploidy and aneuploidy. We discussed triploidy and tetraploidy and on Monday we'll start discussing cases of aneuploidy.

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Our "Genetics News Friday" discussion was a failure and a dissapointment. In spite of having tools to acquire information easier than ever before, nobody brought an idea to discuss, and you can find them everywhere!
Remember, genetics is not just a class to get out of the way. It is a field that has plenty of applications and implications in the real world! Reading or listening to genetics-related news is a good exercise, for this class and for life in general.

Again: Other than the traditional sources of information you can also get information from RSS feeds (the news come TO you), and podcasts (some are literally 1 min 20 secs long...! Can it get any easier?). See Monday's entry (March 23) for some extra details.

No discussion may mean questions about genetic-related news in the quizzes. You pick.

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An RSS Feed looks like this (click for full size image)

And the link will take you to something like this (click for full size image)

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Lecture, chapter 5 - Polygenic inheritance

A gradient of skin tones
click on image for a full size pic
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Today we finished covering chapter 5, on polygenic inheritance.

We discussed concepts like distribution of environmental factors, norm of reaction, and heritability. We also discussed the importance of twin studies in complex traits research, and talked about a couple of examples of polygenic traits in humans: skin color and intelligence.

Tomorrow: Chapter 6, on cytogenetics.

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Lab 03 - Epistasis and hypothesis testing

Tuesday, March 24, 2009

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We did our "corny genetics" lab. Students, working in pairs, analized the expected and observed phenotypic proportions of the F2 generation from a dihybrid cross in genetic corn. They used their expectations and their observations to perchorm a chi-sqare test and relate the results to a potentially epistatic interaction.

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Lecture, chapter 5 - Polygenic inheritance

Today we started covering chapter 5, on polygenic inheritance and interaction with the environment.

We discussed the differences between continuous and discontinuous characters, the definitions of polygenic, multifactorial, and complex traits, and the most common approach to studying the inheritance of continuous variation: Quantitative genetics. Quantitative genetics uses many statistical tools as well as some concepts inherent to it, like the genetic version of regression to the mean, phenotypic distribution, norm of reaction, genetic variance, phenotypic variance, and heritability.

Tomorrow: Lab 3, on Epistasis and hypothesis testing.

On Thursday: More about chapter 5.


Note:

Given the success of the end-of-class discussion on Friday, we will continue having "genetics on the news" discussions in the future, with the possibility of including questions in quizzes. I encourage you to use on-line resources to find genetics news, or let them find you. The main sources would be RSS feeds of publications like Nature, Science, or Scientific American (among MANY others), and scientific podcasts.

Some podcasts have been uploaded to the p-drive and the WebCT site (check them out!), but you can find many more on genetics-related sites. You can get them wherever you want to.
If you don't know were to begin just use iTunes (freeware, availale in Windows and Mac OS X versions) to access the iTunes store and download/subscribe to any of the FREE scientific podcasts available.

Remember, you can find the news, and with RSS feeds and podcast subscriptions the news will find you.

Examples of sites with RSS feeds:

• Scientific American
• Nature
• Science Magazine

If you find any other interesting site, let me know.

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