Towards the delineation of the ancestral eutherian genome organization: comparative genome maps of human and the African elephant (Loxodonta africana) generated by chromosome painting.
This study presents a whole-genome comparison of human and a representative of the Afrotherian clade, the African elephant, generated by reciprocal Zoo-FISH. An analysis of Afrotheria genomes is of special interest, because recent DNA sequence comparisons identify them as the oldest placental mammalian clade. Complete sets of whole-chromosome specific painting probes for the African elephant and human were constructed by degenerate oligonucleotide-primed PCR amplification of flow-sorted chromosomes. Comparative genome maps are presented based on their hybridization patterns. These maps show that the elephant has a moderately rearranged chromosome complement when compared to humans. The human paint probes identified 53 evolutionary conserved segments on the 27 autosomal elephant chromosomes and the X chromosome. Reciprocal experiments with elephant probes delineated 68 conserved segments in the human genome. The comparison with a recent aardvark and elephant Zoo-FISH study delineates new chromosomal traits which link the two Afrotherian species phylogenetically. In the absence of any morphological evidence the chromosome painting data offer the first non-DNA sequence support for an Afrotherian clade. The comparative human and elephant genome maps provide new insights into the karyotype organization of the proto-afrotherian, the ancestor of extant placental mammals, which most probably consisted of 2n=46 chromosomes.
Frönicke
Lutz
L
Comparative Molecular Cytogenetics Section, National Cancer Institute-Genetics Branch, National Cancer Institute-Frederick, Nationa Institutes of Health, Building 560, Room 11-75, Frederick, MD 21702-1201, USA. froenickel@gmx.net
Wienberg
Johannes
J
Stone
Gary
G
Adams
Lisa
L
Stanyon
Roscoe
R
D000818:Animals; D020223:Chromosome Painting; D002877:Chromosomes, Human / Q000235:genetics*; D033481:Chromosomes, Mammalian / Q000235:genetics*; D004606:Elephants / Q000235:genetics*; D019143:Evolution, Molecular; D005434:Flow Cytometry; D016678:Genome; D006801:Humans; D007621:Karyotyping; D013045:Species Specificity