Localization of 5S rDNA and 18S-5.8S-25S rDNA probes in <i>Crinum latifolium</i> L. genome

Abstract

Two conserved repeats viz. 5S rDNA and 18S-5.8S-25S rDNA were used as probes for physical mapping in the genome of Crinum latifolium L. (2n = 3X = 33). Nine out of 11 5S rDNA signals were found in three chromosomes of group VI at metaphase. The 5S rDNA gene array were not AT-rich. Four 18S-5.8S- 25S rDNA signals at interphase, prophase and metaphase showed their stable nature. The contraction and expansion of these signal regions proved the euchromatic nature of 18S-5.8S-25S rDNA. The 5S rDNA and the 18S-5.8S-25S rDNA signals provided useful cytogenetic markers for C. latifolium genome. Patterns of 5S rDNA signals suggested the possible structural aberration in the genome. Although the 5S rDNA sites suggested C. latifolium as autotriploid, 18S-5.8S-25S rDNA sites did not conclude anything about the nature of genome. Unequivocal determination of the nature of genome in C. latifolium remained unanswered.

Key words: rDNA FISH; Crinum latifolium

DOI: 10.3329/bjb.v39i2.7481

Bangladesh J. Bot. 39(2): 199-205, 2010 (December)