Variation in Eukaryotic Genome Size and Sequence
Definition
Genome
The genome is the complete set of genetic instructions that determines the structure, function, and traits of an organism.
- All eukaryotes share the universal genetic code, but their genomes vary greatly in total size and base sequence composition.
- Variation between species is far greater than variation within a species.
Variation in Eukaryotic Genomes
- The genome of an organism is its complete set of DNA, including all coding (genes) and non-coding sequences.
- In eukaryotes, this includes:
- Nuclear DNA
- Mitochondrial DNA
- Chloroplast DNA (in plants)
Although the structure and code of DNA are universal, the total amount and sequence of DNA vary widely between organisms.
Why Genomes Differ
- Differences in eukaryotic genomes arise from two main factors:
- Variation in total DNA content (genome size)
- Larger genomes contain more non-coding DNA, such as introns and repetitive sequences.
- These regions contribute to genome size but not necessarily to gene number.
- Variation in total DNA content (genome size)
