| | |
Summary: Proceedings of the SMBE Tri-National Young Investigators' Workshop 2005
Insight into the Diversity and Evolution of the Cryptomonad
Nucleomorph Genome
Christopher E. Lane,1
Hameed Khan,1
Melissa MacKinnon, Anna Fong,
Stan Theophilou,2
and John M. Archibald
Genome Atlantic and the Canadian Institute for Advanced Research, Program in Evolutionary Biology,
Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
The cryptomonads are an enigmatic group of marine and freshwater unicellular algae that acquired their plastids through
the engulfment and retention of a eukaryotic (``secondary'') endosymbiont. Together with the chlorarachniophyte algae, the
cryptomonads are unusual in that they have retained the nucleus of their endosymbiont in a miniaturized form called
a nucleomorph. The nucleomorph genome of the cryptomonad Guillardia theta has been completely sequenced and with
only three chromosomes and a total size of 551 kb, is a model of nuclear genome compaction. Using this genome as
a reference, we have investigated the structure and content of nucleomorph genomes in a wide range of cryptomonad
algae. In this study, we have sequenced nine new cryptomonad nucleomorph 18S ribosomal DNA (rDNA) genes and
four heat shock protein 90 (hsp90) gene fragments, and using pulsed-field gel electrophoresis and Southern hybridizations,
have obtained nucleomorph genome size estimates for nine different species. We also used long-range polymerase
chain reaction to obtain nucleomorph genomic fragments from Hanusia phi CCMP325 and Proteomonas sulcata
|
