The Eukaryotic Genome & Its Expression
Chapter 14 — How eukaryotic genomes are organized, how genes are transcribed and processed, and the many layers of regulation from chromatin to proteasome.
Section 14.1
What Are the Characteristics of the Eukaryotic Genome?
Bigger genomes, more regulation, loads of noncoding DNA, and an army of transposons.
Core Concept
Eukaryotic vs Prokaryotic Genomes
Larger genomes
Orders of magnitude more DNA.
Orders of magnitude more DNA.
More regulatory sequences
Complex control of gene expression.
Complex control of gene expression.
Much noncoding DNA
Only a small fraction codes for protein.
Only a small fraction codes for protein.
Multiple chromosomes
DNA organized into many linear chromosomes.
DNA organized into many linear chromosomes.
Spatial separation
Transcription in nucleus, translation in cytoplasm → many regulation points.
Transcription in nucleus, translation in cytoplasm → many regulation points.
Transcription & Translation Are Physically Separated
Model Organisms
Eukaryote Model Organisms
| Organism | Common Name | Key Features |
|---|---|---|
| S. cerevisiae | Yeast | 16 chromosomes, 12 Mb. Simplest eukaryote; compartmentalization needs more genes than prokaryotes. |
| C. elegans | Nematode | 1 mm, transparent, ~1,000 cells. Genome 8× yeast. Great developmental model. |
| D. melanogaster | Fruit fly | Extensively used in genetics. Larger genome than C. elegans but fewer genes. Codes for more proteins than genes! |
| A. thaliana | Thale cress | Mustard family plant. Shares genes with animals + plant-specific genes (photosynthesis). |
| O. sativa | Rice | Two subspecies sequenced. Many genes similar to Arabidopsis. |