Abstract
Some species of ciliates undergo massive DNA elimination and genome rearrangement to construct gene-sized "chromosomes" in their somatic nucleus. An example is the extensively scrambled DNA polymerase α gene that is broken into 48 pieces and distributed over two unlinked loci in Stylonychia. To understand the emergence of this complex phenomenon during evolution, we examined DNA polymerase α genes in several earlier diverging species, representing evolutionary intermediates. Mapping these data onto an evolutionary tree suggests that this gene became extensively fragmented and scrambled over evolutionary time through a series of steps, each leading to greater complexity. Our results also suggest a possible mechanism for intron loss by deletion of intron sequences as DNA during development of the somatic nucleus.
Original language | English (US) |
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Pages (from-to) | 15149-15154 |
Number of pages | 6 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 102 |
Issue number | 42 |
DOIs | |
State | Published - Oct 18 2005 |
Externally published | Yes |
Keywords
- Ciliate
- DNA polymerase
- Hypotrich
- Intron loss
- Spirotrich
ASJC Scopus subject areas
- General