Skip to main content
Log in

Chromosomal repatterning in crocodiles: C, G and N-banding and the in situ hybridization of 18S and 26S rRNA cistrons

  • Published:
Genetica Aims and scope Submit manuscript

Abstract

The chromosomes of Crocodylus porosus, C. johnstoni and Caiman crocodilus have been analysed using C, G and N-banding techniques and the in situ hybridization of 18S+26S rRNA cistrons derived from Xenopus. It is clear that in addition to the gross structural changes (robertsonian rearrangements and pericentric inversions) which are known to distinguish these crocodiles, numerous other modes of repatterning have occurred. These involved both the heterochromatic and euchromatic portions of the genome. They appear to be associated with the gross structural changes which have been established, and involve two distinct forms of chromatin transformation.

In addition, the in situ hybridization of 18S+26S rRNA cistrons onto these crocodilian chromosomes has localized the site of nucleolus organizer activity to the C-band positive G-band negative secondary constrictions present in all three species. The significance of these results is discussed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Appels, R. & Honeycutt, R. L., 1985, rDNA: Evolution over a billion years. In: Dutta, S. K. (ed.), DNA Systematics, Vol. II. C.R.C. Press, Bocu Ratan (in press).

    Google Scholar 

  • Bickham, J. W., 1984. Patterns and modes of chromosomal evolution in reptiles. In: Sharma, A. K. & Sharma, A. (eds), Chromosomes in evolution of eukaryote groups. CRC Press, Bocu Ratan. pp 13–40.

    Google Scholar 

  • Bickham, J. W. & Baker, R. J., 1979. Canalization model of chromosomal evolution. In: Models and methodologies in evolutionary theory (J. H. Schwartz & H. G. Rollins, eds), Bull. Carnegie Mus. Nat. Hist. 13: 70–84.

  • Bickham, J. W., Bull, J. J. & Legler, J. M., 1983. Karyotypes and evolutionary relationships of trionychoid Turtles. Cytologia 48: 177–183.

    Google Scholar 

  • Bull, J. J. & Legler, J. M., 1980. Karyotypes of side-necked turtles (Testudines: Pieurodira). Can. J. Zool. 58: 828–841.

    Google Scholar 

  • Cohen, M. M. & Gans, C., 1970. The chromosomes of the order crocodiles. Cytogenetics 9: 81–105.

    Google Scholar 

  • Densmore, L. D., 1983. Biochemical and immunological systematics of the order Crocodilia. Evol. Biol. 16: 397–465.

    Google Scholar 

  • Dowler, R. C. & Bickham, J. W., 1983. Chromosomal relationships of the tortoises family Testudinae. Genetica 58: 189–197.

    Google Scholar 

  • Gerlach, W. L., 1977. N-banded karyotypes of wheat species. Chromosoma 62: 49–56.

    Google Scholar 

  • John, B. & King, M., 1977. Heterochromatin variation in Cryptobothrus chrysophorus 11. Patterns of C-banding, Chromosoma 65: 59–79.

    Google Scholar 

  • John, B. & King, M., 1983. Population cytogenetics of Atractomorpha similis 1. C-band variation. Chromosoma 88: 57–68.

    Google Scholar 

  • John, B., King, M., Schweizer, D. & Mendelak, N., 1984. Equilocality of heterochromatin distribution and heterochromatin heterogeneity in acridid grasshoppers. Chromosoma 91: 185–200.

    Google Scholar 

  • King, M., 1980a. C-banding studies on Australian hylid frogs: secondary constriction structure and the concept of euchromatin transformation. Chromosoma 80: 191–217.

    Google Scholar 

  • King, M., 1981. A cytotaxonomic analysis of Australian hylid frogs of the genus Litoria. Proc. herpetol. Symp. Melb. 169–175.

  • King, M., 1985a. The canalization model of chromosomal evolution: a critique. Systematic Zoology 34: 69–75.

    Google Scholar 

  • King, 1985b. Chromosome markers and their use in phylogeny and systematics. In: Biology of Australasian Frogs and Reptiles (ed. G.Grigg, R.Shine & H.Ehmann) Beatty Surrey, N.S.W. pp. 165–175.

    Google Scholar 

  • King, M. & King, D., 1975. Chromosomal evolution in the lizard genus Varanus (Reptilia) Aust. J. Biol. Sci. 28: 89–108.

    Google Scholar 

  • Macgregor, H. C., Vlad, M. & Barnett, L., 1977. An investigation of some problems concerning nucleolus organizers in salamanders. Chromosoma 59: 283–299.

    Google Scholar 

  • Mahony, M. J. & E. S.Robinson, 1986. Nucleolar organizer region (NOR) location in karyotypes of Australian ground frogs (family Myobatrachidae). Genetica 68: 119–128.

    Google Scholar 

  • Mayr, B., Schweizer, D. & Geber, G., 1984. NOR Activity, heterochromatin differentiation and the Robertsonian polymorphisms in Sus scrofa L. Journ. Hered. 75: 79–80.

    Google Scholar 

  • Mengden, G., 1981. Linear differentiation of the C-band pattern of the W chromosome in snakes and birds. Chromosoma 83: 275–287.

    Google Scholar 

  • Peacock, W. J., Lohe, A., Gerlach, W. L., Dunsmuir, P., Dennis, E. S. & Appels, R., 1978. Fine structure and evolution of DNA in heterochromatin. Cold. Spr. Harb. Symp. quant. Biol. 42: 1121–1135.

    Google Scholar 

  • Saez, F. A., 1963. Gradient of the heterochromatinization in the evolution of the sexual system ‘Neo-X-neo Y’. Port. Acta biol. A, 7: 111–138.

    Google Scholar 

  • Schmid, M., 1980. Chromosome evolution in Amphibia, In: Cytogenetics of Vertebrates (ed. A.Muller) Birkhauser, Basel pp. 44–47.

    Google Scholar 

  • Singh, L., 1972. Evolution of karyotypes in snakes. Chromosoma 38: 185–236.

    Google Scholar 

  • Singh, L. & Ray-Chaudhuri, S. P., 1973. DNA Replication pattern in the chromosomes of Crocodylus pallustris (Lesson). Nucleus 16: 33–37.

    Google Scholar 

  • Sites, J. W., Bickham, J. W., Haiduk, M. W. & Iverson, J. B., 1979. Banded karyotypes of six taxon of kinosternid turtles. Copeia 1979: 692–698.

    Google Scholar 

  • Vitelli, L., Batistoni, R., Andronico, F., Nardi, I. & Barsacchi-Pilone, G., 1982. Chromosomal localization of 18S+28S and 5S ribosomal RNA genes in evolutionary diverse Anuran Amphibians. Chromosoma 84: 475–491.

    Google Scholar 

  • White, M. J. D., Dennis, E. S., Honeycutt, R. L., Contreras, N., & Peacock, W. J., 1982. Cytogenetics of the parthenogenetic grasshopper Warramaba virgo and its bisexual relatives. IX. The ribosomal RNA cistrons. Chromosoma 85: 185–199.

    Google Scholar 

  • Wurster-Hill, D. H. & Gray, C. W., 1973. Giemsa banding patterns in the chromosomes of twelve species of cats (Felidae). Cytogenet. Cell Genet. 12: 377–397.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

King, M., Honeycutt, R. & Contreras, N. Chromosomal repatterning in crocodiles: C, G and N-banding and the in situ hybridization of 18S and 26S rRNA cistrons. Genetica 70, 191–201 (1986). https://doi.org/10.1007/BF00122186

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00122186

Keywords

Navigation