MBE Advance Access first published online on February 6, 2008
This version published online on
Molecular Biology and Evolution, doi:10.1093/molbev/msn032
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The Dynamic Nature of Eukaryotic Genomes
1 Program in Organismic and Evolutionary Biology, University Of Massachusetts, Amherst, MA, USA
2 Department Of Biological Sciences, Smith College, Northampton, MA, USA
Corresponding author: Laura Wegener Parfrey, Lwegener{at}nsm.umass.edu, Program in Organismic and Evolutionary Biology, University Of Massachusetts, Amherst, MA 01003, Phone: 1(413) 585-3850, Fax: 1(413) 585-3786
Received for publication November 27, 2007. Revision received January 23, 2008. Accepted for publication January 29, 2008.
Analyses of diverse eukaryotes reveal that genomes are dynamic, sometimes dramatically so. In numerous lineages across the eukaryotic tree of life, DNA content varies within individuals throughout life cycles and among individuals within species. Discovery of examples of genome dynamism is accelerating as genome sequences are completed from diverse eukaryotes. Though much is known about genomes in animals, fungi, and plants, these lineages represent only three of the 60-200 lineages of eukaryotes. Here, we discuss diverse genomic strategies in exemplar eukaryotic lineages, including numerous microbial eukaryotes, to reveal dramatic variation that challenges established views of genome evolution. For example, in the life cycle of some members of the radiolaria ploidy increases from haploid (N) to approximately 1000N, while intrapopulation variability of the enteric parasite Entamoeba ranges from 4N to 40N. Variation has also been found within our own species, with substantial differences in both gene content and chromosome lengths between individuals. Data on the dynamic nature of genomes shift the perception of the genome from being fixed and characteristic of a species (typological) to plastic due to variation within and between species.
Key Words: Polyploidy Microbial Eukaryotes Genome Evolution Epigenetics Life Cycle Variation Genome Rearrangements