The karyotypes,C-bands patterns and Ag-NORs of Epinephelus malabaricus

The chromosome specimens of Epinephelus malabaricus (Bloch &Schneider) were obtained from metaphase of kidney cell by viv2injection of PHA and cultivation of colchicines , hypatoic2air drying technique , and then by studying their Giemsa stain , C2bands and Ag2NORs. The results were as follows : 1) E. malabaricus had a diploid chromosome number of 48 and its karyotype formula was 48t , NF = 48 ,sex chromosome was not found;2) There was a pair of chromosomes with secondary constriction close to the centromere of chromosomet24; 3)1-4nucleoliappearedinthenucleusofinterphase,55%nucleihadlnucleolusandonly2%for4nucleoli;4) Ag2NORs appeared in the chromosome t 24 of 50 %metaphase ,sometimes in the chromosome t5 ,but not in other chromosomes ;5) The Ag2NORs polymorphisms were individually specific ,1 -4 pairs of the number ,and the frequency of 4 Ag2NORs were lowest ; 6) The secondary constrictions and positive C2bands were coincident , close centromere the chromosome , and mass constrictive heterochromatinsappearedinthatregion;7)Allthecentromeresofchromoso(tothe) mesweredarkl(of) y stained C2bands ,and the whole arm of chromosome t 24 and its centromere were same positive C2bands. 8) The evolutive regulation of the karyotype and the developing mechanism of Ag2NORs and C2bands were discussed.