Abstract
Krill (family Euphausiidae) represent some of the most abundant organisms in the both northern and southern oceanic environments and provide food for various animals including humans. Despite their importance, little is known about krill from a genomic standpoint, even with regard to basic properties such as total genome size. This study provides genome size estimates for six species of krill from both the North Atlantic and Southern Oceans which are the first such estimates for any species of euphausiid. Genome size estimates were obtained using both flow cytometry and Feulgen image analysis densitometry with chicken and trout blood as internal standards. Haploid genome sizes ranged from 12.77 to 48.53 pg, providing roughly fourfold variation within these six species alone. With such large estimates, sequencing of a krill genome will currently be costly and laborious, but further studies should be conducted to determine the composition of these exceptionally large genomes.
References
Adams MD, Celniker SE, Holt RA et al (2000) The genome sequence of Drosophila melanogaster. Science 287:2185–2195
Bennett MD, Leitch IJ (2010) Plant DNA C-values Database. Kew Royal Botanical Gardens. http://data.kew.org/cvalues/
Doležel J, Binarová P, Lucretti S (1989) Analysis of nuclear DNA content in plant cells by flow cytometry. Biol Plantarum 31:113–120
Dorward HM, Wyngaard GA (1997) Variability and pattern of chromatin diminution in the freshwater Cyclopidae (Crustacea: Copepoda). Arch Hydrobiol 107:447–465
Gregory TR (2001) Coincidence, coevolution, or causation? DNA content, cell size, and the C-value enigma. Biol Rev 76:65–101
Gregory TR (2011) Animal genome size database. http://www.genomesize.com
Gregory TR, Hebert PDN, Kolasa J (2000) Evolutionary implications of the relationship between genome size and body size in flatworms and copepods. Heredity 84:201–208
Hardie DC, Gregory TR, Hebert PDN (2002) From pixels to picograms: a beginners’ guide to genome quantification by Feulgen Image Analysis Denistometry. J Histochem Cytochem 50:735–749
Jarman S, Elliott N, Nicol S, McMinn A, Newman S (1999) The base composition of the krill genome and its potential susceptibility to damage by UV-B. Antarct Sci 11:23–26
Jarman SN, Elliott NG, Nicol S, McMinn A (2000) Molecular phylogenetics of circumglobal Euphausia species (Euphausiacea: Crustacea). Can J Aquat Sci 57:51–58
Kelly LJ, Leitch IJ (2011) Exploring giant plant genomes with next-generation sequencing technology. Chromosome Res 19:939–953
Martin JW, Davis GE (2001) An updated classification of the recent Crustacea. Science Series (Los Angeles) 39. Natural History Museum of Los Angeles County: Los Angeles. VII, 123 pp
Ngan PV, Gomes V, Suzuki H, Passos MJACR (1989) Preliminary study on chromosomes of Antarctic krill, Euphausia superba Dana. Polar Biol 10:149–150
Nicol S, Foster J (2003) Recent trends in the fishery for Antarctic krill. Aquat Living Resour 16:42–45
Rees DJ, Dufresne F, Glémet H, Belzile C (2007) Amphipod genome sizes: first estimates for Arctic species reveal genomic giants. Genome 50:151–158
Rees DJ, Belzile C, Glémet H, Dufresne F (2008) Large genomes among caridean shrimp. Genome 51:159–163
Thiriot-Quiévreux C, Leitão A, Cuzin-Roudy J (1998) Chromosome diversity in Mediterranean and Antarctic Euphausiid species (Euphausiacea). J Crustacean Biol 18:290–297
Vergilino R, Belzile C, Dufresne D (2009) Genome size evolution and polyploidy in the Daphnia pulex complex (Cladocera: Daphniidae). Biol J Linn Soc 97:68–79
Acknowledgments
This study was supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant to Dr. Ryan Gregory and an NSERC Postgraduate Scholarship to Nicholas Jeffery. Thanks to the British Antarctic Survey (BAS) and the French Polar Institute (IPEV) for providing all specimens for this study. Angus Atkinson of the BAS Ecosystems programme provided E. superba, while E. frigida¸ E. triacantha, and Thysanoessa sp. were provided by Gabriele Stowasser from the DISCOVERY2010 programme at the BAS. Dr. Geraint Tarling provided M. norvegica. Dr Melody Clark (BAS) collated the samples for this study and arranged dispatch to Canada. Thanks also to Dr. Jean-Yves Toullec for providing specimens of E. crystallorophias and to the crew of the Astrolabe for specimen collection. Thanks to Dr. Ryan Gregory, Dr. Melody Clark, and Tyler Elliott for providing useful comments on early drafts of the manuscript.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Jeffery, N.W. The first genome size estimates for six species of krill (Malacostraca, Euphausiidae): large genomes at the north and south poles. Polar Biol 35, 959–962 (2012). https://doi.org/10.1007/s00300-011-1137-4
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00300-011-1137-4