- THIS ARTICLE
- Full Text
- Full Text (PDF)
- Data Supplement
-
All Versions of this Article:
genetics.105.050229v1
175/1/311 most recent - Alert me when this article is cited
- Alert me if a correction is posted
- SERVICES
- Email this article to a friend
- Similar articles in this journal
- Similar articles in PubMed
- Alert me to new issues of the journal
- Download to citation manager
- Reprints & Permissions
- CITING ARTICLES
- Citing Articles via HighWire
- Citing Articles via Google Scholar
- GOOGLE SCHOLAR
- Articles by McTaggart, S. J.
- Articles by Crease, T. J.
- Search for Related Content
- PUBMED
- PubMed Citation
- Articles by McTaggart, S. J.
- Articles by Crease, T. J.
Originally published as Genetics Published Articles Ahead of Print on November 16, 2006.
Genetics, Vol. 175, 311-320, January 2007, Copyright © 2007
doi:10.1534/genetics.105.050229
Rates of Recombination in the Ribosomal DNA of Apomictically Propagated Daphnia obtusa Lines
Seanna J. McTaggart*,1,
Jeffry L. Dudycha
,2,
Angela Omilian and
Teresa J. Crease*,3
* Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada and Department of Biology, Indiana University, Bloomington, Indiana 47405-3700
3 Corresponding author: Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
E-mail: tcrease{at}uoguelph.ca
Ribosomal (r)DNA undergoes concerted evolution, the mechanisms of which are unequal crossing over and gene conversion. Despite the fundamental importance of these mechanisms to the evolution of rDNA, their rates have been estimated only in a few model species. We estimated recombination rate in rDNA by quantifying the relative frequency of intraindividual length variants in an expansion segment of the 18S rRNA gene of the cladoceran crustacean, Daphnia obtusa, in four apomictically propagated lines. We also used quantitative PCR to estimate rDNA copy number. The apomictic lines were sampled every 5 generations for 90 generations, and we considered each significant change in the frequency distribution of length variants between time intervals to be the result of a recombination event. Using this method, we calculated the recombination rate for this region to be 0.02–0.06 events/generation on the basis of three different estimates of rDNA copy number. In addition, we observed substantial changes in rDNA copy number within and between lines. Estimates of haploid copy number varied from 53 to 233, with a mean of 150. We also measured the relative frequency of length variants in 30 lines at generations 5, 50, and 90. Although length variant frequencies changed significantly within and between lines, the overall average frequency of each length variant did not change significantly between the three generations sampled, suggesting that there is little or no bias in the direction of change due to recombination.
This article has been cited by other articles:
 |
|
 |
|
  C. R. Haag, S. J. McTaggart, A. Didier, T. J. Little, and D. Charlesworth Nucleotide Polymorphism and Within-Gene Recombination in Daphnia magna and D. pulex, Two Cyclical Parthenogens Genetics, May 1, 2009; 182(1): 313 - 323. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Zhang, M. T. Eickbush, and T. H. Eickbush Role of Recombination in the Long-Term Retention of Transposable Elements in rRNA Gene Loci Genetics, November 1, 2008; 180(3): 1617 - 1626. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. H. Eickbush and D. G. Eickbush Finely Orchestrated Movements: Evolution of the Ribosomal RNA Genes Genetics, February 1, 2007; 175(2): 477 - 485. [Abstract] [Full Text] [PDF]
|
|
|