title: Comparative cytogenetics of the African elephant (Loxodonta africana) and Asiatic elephant (Elephas maximus).
abstract: 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 pairs. E. maximus differed by having one less acrocentric and one additional submetacentric pair due to either a heterochromatic arm addition or deletion 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 elements and were homologous. However, the small acrocentric Y chromosomes differed; in E. maximus it was slightly larger and had more distinct G-bands than its counterpart in L. africana. Extant Elephantidae appear to be relatively conservative in their rates of chromosomal change compared to some other mammalian families. The high-quality banded karyotypes presented here should prove useful as references in future chromosome analyses of elephant populations and in comparative cytogenetic studies with other ungulate orders.
authors.affiliation: The Zoological Society of San Diego, Center for Reproduction of Endangered Species, San Diego, CA 91112-0551, USA. mhouck@sandiegozoo.org
authors.forename: M L
authors.initials: ML
authors.lastname: Houck
authors.forename: A T
authors.initials: AT
authors.lastname: Kumamoto
authors.forename: D S
authors.initials: DS
authors.lastname: Gallagher
authors.forename: K
authors.initials: K
authors.lastname: Benirschke
mesh_terms: D000349:Africa; D000818:Animals; D001208:Asia; D002871:Chromosome Banding; D002875:Chromosomes / Q000235:genetics*; D004606:Elephants / Q000235:genetics*; D019143:Evolution, Molecular; D005260:Female; D007621:Karyotyping; D008297:Male