title: Evolutionary movement of centromeres in horse, donkey, and zebra.
abstract: Centromere repositioning (CR) is a recently discovered biological phenomenon consisting of the emergence of a new centromere along a chromosome and the inactivation of the old one. After a CR, the primary constriction and the centromeric function are localized in a new position while the order of physical markers on the chromosome remains unchanged. These events profoundly affect chromosomal architecture. Since horses, asses, and zebras, whose evolutionary divergence is relatively recent, show remarkable morphological similarity and capacity to interbreed despite their chromosomes differing considerably, we investigated the role of CR in the karyotype evolution of the genus Equus. Using appropriate panels of BAC clones in FISH experiments, we compared the centromere position and marker order arrangement among orthologous chromosomes of Burchelli's zebra (Equus burchelli), donkey (Equus asinus), and horse (Equus caballus). Surprisingly, at least eight CRs took place during the evolution of this genus. Even more surprisingly, five cases of CR have occurred in the donkey after its divergence from zebra, that is, in a very short evolutionary time (approximately 1 million years). These findings suggest that in some species the CR phenomenon could have played an important role in karyotype shaping, with potential consequences on population dynamics and speciation.
authors.affiliation: Department of Genetics and Microbiology, University of Bari, Via Amendola 165/A, 70126 Bari, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Carbone
authors.forename: Solomon G
authors.initials: SG
authors.lastname: Nergadze
authors.forename: Elisa
authors.initials: E
authors.lastname: Magnani
authors.forename: Doriana
authors.initials: D
authors.lastname: Misceo
authors.forename: Maria
authors.initials: M
authors.lastname: Francesca Cardone
authors.forename: Roberta
authors.initials: R
authors.lastname: Roberto
authors.forename: Livia
authors.initials: L
authors.lastname: Bertoni
authors.forename: Carmen
authors.initials: C
authors.lastname: Attolini
authors.forename: Maria
authors.initials: M
authors.lastname: Francesca Piras
authors.forename: Pieter
authors.initials: P
authors.lastname: de Jong
authors.forename: Terje
authors.initials: T
authors.lastname: Raudsepp
authors.forename: Bhanu P
authors.initials: BP
authors.lastname: Chowdhary
authors.forename: Gérard
authors.initials: G
authors.lastname: Guérin
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Archidiacono
authors.forename: Mariano
authors.initials: M
authors.lastname: Rocchi
authors.forename: Elena
authors.initials: E
authors.lastname: Giulotto
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002503:Centromere / Q000235:genetics* / Q000648:ultrastructure*; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D018397:Equidae / Q000235:genetics*; D005819:Genetic Markers; D006736:Horses / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D013045:Species Specificity; D013997:Time Factors
chemical_list: D005819:Genetic Markers