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A Chimeric Chromosome in the Ciliate Oxytricha Resulting from Duplication

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Abstract

In a process similar to exon splicing, ciliates use DNA splicing to produce a new somatic macronuclear genome from their germline micronuclear genome after sexual reproduction. This extra layer of DNA rearrangement permits novel mechanisms to create genetic complexity during both evolution and development. Here we describe a chimeric macronuclear chromosome in Oxytricha trifallax constructed from two smaller macronuclear chromosomes. To determine how the chimera was generated, we cloned and sequenced the corresponding germline loci. The chimera derives from a novel locus in the micronucleus that arose by partial duplication of the loci for the two smaller chromosomes. This suggests that an exon shuffling-like process, which we call MDS shuffling, enables ciliates to generate novel genetic material and gene products using different combinations of genomic DNA segments.

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Fig. 1
Fig. 2

Abbreviations

MAC:

Macronucleus

MIC:

Micronucleus

MDS:

Macronuclear-destined sequence

IES:

Internal-eliminated sequence

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Acknowledgments

The authors thank the rest of the Landweber lab members for helpful discussion and testing, and Jingmei Wang for assistance. This study was supported by National Institute of General Medical Sciences Grant GM59708 and National Science Foundation Grant 0622112.

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Authors and Affiliations

  1. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA

    Yi Zhou, Helmae Wubneh, Clayton Schwarz & Laura F. Landweber

Authors
  1. Yi Zhou
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  2. Helmae Wubneh
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  3. Clayton Schwarz
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  4. Laura F. Landweber
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Corresponding author

Correspondence to Laura F. Landweber.

Additional information

Yi Zhou and Helmae Wubneh have contributed equally to this work.

Genbank entries MAC A: FJ346571; MAC B: FJ346573; MAC C haplotype 1: FJ346575; MAC C haplotype 2: FJ346577; MIC A: FJ346570; MIC B: FJ346572; MIC C haplotype 1: FJ346574; MIC C haplotype 2: FJ346576; MIC D: FJ349559.

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Zhou, Y., Wubneh, H., Schwarz, C. et al. A Chimeric Chromosome in the Ciliate Oxytricha Resulting from Duplication. J Mol Evol 73, 70–73 (2011). https://doi.org/10.1007/s00239-011-9464-1

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  • DOI: https://doi.org/10.1007/s00239-011-9464-1

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