Basic cytogenetic data, such as diploid number and general chromosome morphology, are available for many reptilian species. Here we present a detailed cytogenetic examination of the saltwater crocodile (Crocodylus porosus) karyotype, including the creation of the first fully annotated G-band standard ideogram for any crocodilian species. The C. porosus karyotype contains macrochromosomes and has a diploid number of 34. This study presents a detailed description of each chromosome, permitting unambiguous chromosome identification. The fully annotated standardized C. porosus ideogram provides the backbone to a standard nomenclature system which can be used to accurately identify specific band locations. Seven microsatellite containing fosmid clones were fluorescently labeled and used as fluorescent in situ hybridization (FISH) probes for physical localization. Chromosome locations for each of these FISH probes were successfully assigned, demonstrating the utility of the fully annotated ideogram for genome mapping.

1.
Bowling AT, Breen M, Chowdhary BP, Hirota K, Lear T, et al: International system for cytogenetic nomenclature of the domestic horse. Report of the Third International Committee for the Standardization of the Domestic Horse Karyotype, Davis, CA, USA, 1996. Chromosome Res 5:433–443 (1997).
2.
Chavananikul V, Suwattana D, Wattanodorn S, Koykul W: Karyotypes and NORs banding patterns in Crocodylus siamensis and Crocodylus porosus. Proceedings of the 6th World Congress on genetics applied to livestock production, Armidale, Australia 25:319–322 (1998).
3.
Cho KW, Youn HY, Watari T, Tsujimoto H, Hasegawa A, Satoh H: A proposed nomenclature of the domestic cat karyotype. Cytogenet Cell Genet 79:71–78 (1997).
4.
Cohen MM, Clark HF: The somatic chromosomes of five Crocodilian species. Cytogenetics 6:193–203 (1967).
5.
Cohen MM, Gans C: The chromosomes of the order Crocodilia. Cytogenetics 9:81–105 (1970).
6.
Di Meo GP, Perucatti A, Floriot S, Hayes H, Schibler L, et al: An extended river buffalo (Bubalus bubalis, 2n = 50) cytogenetic map: assignment of 68 autosomal loci by FISH-mapping and R-banding and comparison with human chromosomes. Chromosome Res 16:827–837 (2008).
7.
Ford CE, Pollock DL, Gustavsson I: Proceedings of the first international conference for the standardisation of banded karyotypes of domestic animals. University of Reading, Reading, England. 2nd–6th August 1976. Hereditas 92:145–162 (1980).
8.
Francke U, Oliver N: Quantitative analysis of high-resolution trypsin-Giemsa bands on human prometaphase chromosomes. Hum Genet 45:137–165 (1978).
9.
Gardner R, Sutherland G: Chromosome abnormalities and genetic counseling p. 447 (Oxford University Press, Oxford 2004).
10.
Glenn TC, Schable NA: Isolating microsatellite DNA loci; in Zimmer E, Roalson E (eds): Methods in enzymology 395, molecular evolution: Producing the biochemical data, part b (Academic Press, San Diego 2005).
11.
Hamta A, Adamovic T, Samuelson E, Helou K, Behboudi A, Levan G: Chromosome ideograms of the laboratory rat (Rattus norvegicus) based on high-resolution banding, and anchoring of the cytogenetic map to the DNA sequence by FISH in sample chromosomes. Cytogenet Genome Res 115:158–168 (2006).
12.
Howell WM, Black DA: Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method. Experientia 36:1014–1015 (1980).
13.
ISCN: ISCN (2009): An International System for Human Cytogenetic Nomenclature (S. Karger AG, Basel 2009).
14.
ISCNDB 2000: International System for Chromosome Nomenclature of Domestic Bovids. Cytogenet Cell Genet 92:283–299 (2001).
15.
Kawagoshi T, Nishida C, Ota H, Kumazawa Y, Endo H, Matsuda Y: Molecular structures of centromeric heterochromatin and karyotypic evolution in the Siamese crocodile (Crocodylus siamensis) (Crocodylidae, Crocodylia). Chromosome Res 16:1119–1132 (2008).
16.
King M, Honeycutt R, Contreras N: Chromosomal repatterning in crocodiles; C, G and N-banding and the in situ hybridisation of 18S and 26S rRNA cistrons. Genetica 70:191–201 (1986).
17.
Lloyd M, Morris PJ: Phlebotomy techniques in Crocodilians. Bull Assoc Rep Amphib Vet 9:12–14 (1999).
18.
Miles LG, Isberg SR, Glenn TC, Lance SL, Dalzell P, Thomson PC, Moran C: A genetic linkage map for the saltwater crocodile (Crocodylus porosus). BMC Genomics 10:339 (2009a).
19.
Miles LG, Lance SL, Isberg SR, Moran C, Glenn TC: 253 novel polymorphic microsatellites for the saltwater crocodile (Crocodylus porosus). Conserv Genet 10:963–980 (2009b).
20.
Modi WS, Crews D: Sex chromosomes and sex determination in reptiles. Curr Opin Genet Dev 15:660–665 (2005).
21.
Moorhead PS, Nowell PC, Mellman WJ, Battips DM, Hungerford DA: Chromosome preparations of leukocytes cultured from human peripheral blood. Exp Cell Res 20:613–616 (1960).
22.
Nesbitt MN, Francke U: A system of nomenclature for band patterns of mouse chromosomes. Chromosoma 41:145–158 (1973).
23.
Olmo E: Trends in the evolution of reptilian chromosomes. Integr Comp Biol 148:486–493 (2008).
24.
Seabright M: A rapid banding technique for human chromosomes. Lancet 2:971–972 (1971).
25.
Shan X, Ray D, Bunge J, Peterson D: A bacterial artificial chromosome library for the Australian saltwater crocodile (Crocodylus porosus) and its utilization in gene isolation and genome characterization. BMC Genomics 10 Suppl 2:S9 (2009).
26.
Switonski M, Reimann N, Bosma AA, Long S, Bartnitzke S, et al: Report on the progress of standardization of the G-banded canine (Canis familiaris) karyotype. Committee for the standardized karyotype of the dog (Canis familiaris). Chromosome Res 4:306–309 (1996).
27.
Trere D: AgNOR staining and quantification. Micron 31:127–131 (2000).
28.
Valleley EM, Harrison CJ, Cook Y, Ferguson MW, Sharpe PT: The karyotype of Alligator mississippiensis, and chromosomal mapping of the ZFY/X homologue, Zfc. Chromosoma 103:502–507 (1994).
29.
Wang K, Guo W, Zhang T: Development of one set of chromosome-specific microsatellite-containing BACs and their physical mapping in Gossypium hirsutum L. Theor Appl Genet 115:675–682 (2007).
30.
Yoshido A, Bando H, Yasukochi Y, Sahara K: The Bombyx mori karyotype and the assignment of linkage groups. Genetics 170:675–685 (2005).
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.