Evolutionary movement of centromeres in horse, donkey, and zebra.
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.
Carbone
Lucia
L
Department of Genetics and Microbiology, University of Bari, Via Amendola 165/A, 70126 Bari, Italy.
Nergadze
Solomon G
SG
Magnani
Elisa
E
Misceo
Doriana
D
Francesca Cardone
Maria
M
Roberto
Roberta
R
Bertoni
Livia
L
Attolini
Carmen
C
Francesca Piras
Maria
M
de Jong
Pieter
P
Raudsepp
Terje
T
Chowdhary
Bhanu P
BP
Guérin
Gérard
G
Archidiacono
Nicoletta
N
Rocchi
Mariano
M
Giulotto
Elena
E
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
D005819:Genetic Markers