The GTG-banded karyotype and telomere fish in Asian elephants (Elephas maximus)

Lymphocyte cultures were performed for chromosome preparations from 70 Asia n elephants (Elephas maximus) held captive in the province of Lampang, Thai land. The elephant karyotype was demonstrated using Giemsa staining and GTG banding techniques. The diploid number (2n) was 56 or 28 chromosome pairs, consisting of 6 pairs of bi-armed chromosomes and the rest of 21 chromosom e pairs were telocentric. The chromosomes were classified and numbered acco rding to size, centromere position and banding patterns. Chromosome one exh ibited a secondary constriction on the proximal third of the p-arm whereas chromosomes 2 to 6 showed faint bands probably due to their heterochromatic constitution. The X chromosome was medium submetacentric with distinctive bands while the Y was a small telocentric chromosome with a dark band aroun d the centromere. An idiogram of total 216 bands was established according to the GTG-bands which will be useful for physical gene mapping. Telomeres of Asian elephants' chromosomes were localized using a fluorescein-conjugat ed peptide nucleic acid (PNA) probe containing a telomeric sequence (TTAGGG ). Fluorescence in situ hybridization (FISH) revealed the locations of four spots of telomeres on all including the sex chromosomes. Our observations demonstrated that telomeric DNA sequences have been well conserved in the A sian elephants similar to those shown in almost all vertebrates.