Lecture - Variations in gene expression: A conclusion to chapter 4

Today we covered the last portion of chapter 4, focused on variations of gene expression, and some examples. We explained the following key concepts:

• Age-related phenotypic expression
• Penetrance
• Expressivity

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Lecture - More about pedigree analysis

We covered the four remaining modes of inheritance of Mendelian traits in humans (chapter 4):

• X-linked dominant
• X-linked recessive
• Y-linked (paternal inheritance)
• Mitochondrial (maternal inheritance)

We introuduced the concept of variation of gene expression.

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(Friday December 19th) Lecture - Pedigree analysis

A pedigree is a graphic way to present family information using standardized symbols (mainly squares and circles). Using Mendelian principles a pedigree can be analyzed to determine if a trait is autosomal or sex-linked, dominant or recessive, and calculate the probability of parents transmitting the trait to their offspring.
Since it is unethical to do controled crosses in humans, pedigree analyses are the tool for geneticists to study transmission genetics in this case.

We covered the first part of chapter 4 in the book. We explained what a pedigree is, how Mendelian traits in humans are being catalogued in the OMIM database, and we listed the characteristics of the first modes of inheritance in humans (autosomal recessive and autosomal dominant).

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