Comparative cytogenetics of the African elephant (Loxodonta africana)and Asiatic elephant (Elephas maximus)

G- and C-banded karyotypes of the two extant species of the mammalian order Proboscidea are presented for the first time. Chromosome complements were 2n = 56 in both Loxodonta africana and Elephas maximus. Comparisons between the species demonstrated a high level of chromosome band homology, with 26 conserved autosomal pairs. The normal diploid karyotype of L. africana had 25 acrocentric/telocentric and two metacentric/submetacentric autosomal pa irs. E. maximus differed by having one less acrocentric and one additional submetacentric pair due to either a heterochromatic arm addition or deletio n involving autosomal pair 27. Several acrocentric autosomes of L. africana exhibited small short arms that were absent in homologous chromosomes of E . maximus. The X chromosomes in both species were large submetacentric elem ents and were homologous. However, the small acrocentric Y chromosomes diff ered; in E. maximus it was slightly larger and had more distinct G-bands th an its counterpart in L. africana. Extant Elephantidae appear to be relativ ely conservative in their rates of chromosomal change compared to some othe r mammalian families. The high-quality banded karyotypes presented here sho uld prove useful as references in future chromosome analyses of elephant po pulations and in comparative cytogenetic studies with other ungulate orders . Copyright (C) 2001 S. Karger AG, Basel.