Lecture Notes: Gene Expression and Experimental Approaches

Genomic Equivalence and Differential Gene Expression

Genomic Equivalence:
- All somatic cells contain the same genetic material.
- Different cell types (e.g., neurons, fibroblasts) have the same set of genes.
Differential Gene Expression:
- Different cells express different sets of genes, leading to different functions, sizes, and shapes.

DNA: Stores information as genes.
Transcription: RNA polymerase II transcribes RNA from DNA.
- Introns (non-coding) are removed via splicing, leaving exons.
- Non-Coding RNAs: Some RNAs function without being translated.
Translation: mRNA is translated by ribosomes to produce proteins.
- Proteins perform functions necessary for development.

In Situ Hybridization: Detects when and where mRNA is expressed.
- Colorimetric Detection: Produces a blue-purple color.
- Fluorescent In Situ Hybridization (FISH): Uses fluorescence for detection.
Microarray Analysis:
- Glass slides with DNA spots detect mRNA levels using fluorescence.
- Important for genome-wide expression analysis.
RNA Sequencing (RNA-seq):
- Utilizes high-throughput sequencing to determine mRNA expression levels.

Immunostaining: Uses antibodies to detect proteins.
- Antibodies bind to target proteins (antigens).
- Example: Zebrafish embryo stained for nervous system proteins.
Proteomics Techniques:
- Analyze multiple proteins simultaneously.
- More challenging than RNA analyses.

Genetically Modified Organisms:
- Replace gene of interest with a reporter gene (e.g., GFP).
- Track gene expression in live organisms.
- Example: GFP-tagged proteins in C. elegans embryos.

Changes in gene expression are crucial for developing specialized cells and tissues.
Techniques discussed allow for tracking these changes in model organisms.
Further videos will cover detailed workings of these techniques.