LectureChapter 8 - DNA structure and chromosomal organizationChapter 9 - From genes to proteins

Today we discussed the basics of RNA structure and pointed out basic differences between it and DNA.  We then had an overview of how DNA is condensed into chromosomes and how it is replicated.

Watch the following video or access this link to understand the main features of the DNA replication process

We also started chapter 9, on how genetic information is transcribed into mRNA and translated into proteins.  We briefly recapped how Beadle and Tatum confirmed that there was a connection between genes and proteins in the 1940sand how their famous quote ("one gene, one enzyme") has been modified, as discoveries have been made, to make it more accurate.

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Chapter 8 - DNA structure and chromosomal organization

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Rosalind Franklin and her "photo 51"
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We continued discussing the history of how the structure of DNA was discovered, including the injustice  (alleged by many) commited towards Rosalind Franklin, who took the X-ray diffraction image known as "photo 51", which was key for Watson and Crick to resolve the structure of the double helix. Her collaborator, Maurice Wilkins showed Watson the picture, without Franklin's knowledge, and the latter failed to acknowledge the fact that HER image put him and Crick on the road to become the icons they officially are today.

Then we talked about the structure of nucleotides and how they are assembled to form the famous DNA double helix.

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Lab 05 - Heritability

In today's lab we focused in calculating heritability, the proportion of phenotypic variance explained by genetic factors.

We covered two approaches to calculating heritability:

1. Broad sense heritability: It reflects all possible genetic contributions to a population's phenotypic variance like effects due to allelic variation (additive variance), dominance/recessiveness, polygenic interactions, and well as maternal and paternal effects.
2. Narrow sense heritability: It quantifies only the proportion of phenotypic variation explained by additive contribution of the genes that control the trait, ignoring all other genetic contributions.

We calculated broad sense heritability with data collected from student's fingerprints, specifically total ridge count. And narrow sense heritability was calculated based on students' heights in inches, as well as the heights of their siblings, parents, and parents' siblings.

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LectureChapter 6 - CytogeneticsChapter 8 - DNA structure and chromosomal organization

Today we finished the cytogenetics chapter, with a discussion on uniparental disomy (UPD) and fragile sites, the remaining chromosomal abnormalities.

And we started on chapter 8, on DNA structure and chromosomal organization, with a brief discussion on some science history events that led to the discovery of the structure of DNA.  On Wednesday we'll pick up on  the drama that unfolded around Rosalind Franklin's (involuntary? not-acknowledged?) involvement in the process of deciphering the structure of the now famous double helix.

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Exam 1

Friday, April 1, 2011

Stats on exam 1:

(clic pic for full size image)

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