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Modern Genetic Analysis
2. The Structure of Genes and Genomes
Key Concepts

DNA is a double helix consisting of two intertwined antiparallel and complementary nucleotide chains.
A genome is composed of one or more DNA molecules, each organized as a chromosome.
Prokaryotic genomes are mostly single circular chromosomes.
Eukaryotic genomes contain nuclear and organellar components.
The nuclear complement of the genome consists of one or two sets of linear chromosomes.
In a nuclear chromosome DNA is wound around histone proteins, resulting in a coiled, compact, linear structure.
A gene is a chromosomal region capable of making a functional transcript.
The genes of many eukaryotic species contain noncoding regions called introns.

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