Lecture, chapter 4 - Pedigree analysis

Today we started chapter 4, on pedigree analysis.

We discussed the utility of using pedigree analysis to study human genetics. We had an overview of what the main six modes of inheritance are, and how they can be identified in a pedigree.

We discussed in detail the characteristics of the autosomal recessive mode of inheritance, and provided examples: cystic fibrosis and sickle cell anemia.

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Lab 2 - Mendelian genetics

Today we did lab 2, on Mendelian genetics.

The goal of this lab was to observe the phenotypic consequences of the principles of segregation and independent assortment. We used the free software DrosophiLab to simulate experimental crosses with fruit flies. Most of the crosses were testcrosses, meaning that one of the individuals involved in the cross was homozygous recessive for the trait being considered (in this case a homozygous recessive individual would be a mutant fly. The mutation would have an observable phenotype).

A series of three experiments considering one trait, two traits controlled by genes in different chromosomes, and one trait controlled by a gene in a sex chromosome should have shown students how to see the effects of Mendel's principles in an experiment.

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Lecture, chapter 3 - Mendelian genetics

Today we finished chapter 3, on Mendelian genetics.

We talked about how human genes do follow Mendel's principles, and talked about a few examples of traits on which Mendelian inheritance can be studied by observing phenotypes.

We also discussed how there are cases in which there are deviations from Mendelian phenotypic proportions:

• Incomplete dominance
• Codominance
• Multiple alleles
• Gene interactions (including epistasis)

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Lecture, chapter 3 - Mendelian genetics

Friday, March 12, 2010

Today we started covering chapter 3, on Mendelian genetics (a.k.a transmission genetics). We talked about Mendel's classic experiments with pea plants and how he ended up formulating his principles:

• Principle of segregation
• Principle of independent assortment

On Monday: Do Mendel's principles apply to humans?

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