Eight million years of maintained heterozygosity in chromosome homologs of cercopithecine monkeys.
Chromosoma
; 129(1): 57-67, 2020 03.
Article
en En
| MEDLINE
| ID: mdl-31925526
ABSTRACT
In the Cercopithecini ancestor two chromosomes, homologous to human chromosomes 20 and 21, fused to form the Cercopithecini specific 20/21 association. In some individuals from the genus Cercopithecus, this association was shown to be polymorphic for the position of the centromere, suggesting centromere repositioning events. We set out to test this hypothesis by defining the evolutionary history of the 20/21 association in four Cercopithecini species from three different genera. The marker order of the various 20/21 associations was established using molecular cytogenetic techniques, including an array of more than 100 BACs. We discovered that five different forms of the 20/21 association were present in the four studied Cercopithecini species. Remarkably, in the two Cercopithecus species, we found individuals in which one homolog conserved the ancestral condition, but the other homolog was highly rearranged. The phylogenetic analysis showed that the heterozygosity in these two species originated about 8 million years ago and was maintained for this entire arc of time, surviving multiple speciation events. Our report is a remarkable extension of Dobzhansky's pioneering observation in Drosophila concerning the maintenance of chromosomal heterozygosity due to selective advantage. Dobzhansky's hypothesis recently received strong support in a series of detailed reports on the fruit fly genome. Our findings are first extension to primates, indeed to Old World monkeys phylogenetically close to humans of an analogous situation. Our results have important implications for hypotheses on how chromosome rearrangements, selection, and speciation are related.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Haplorrinos
/
Evolución Molecular
/
Cromosomas de los Mamíferos
/
Heterocigoto
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Chromosoma
Año:
2020
Tipo del documento:
Article
País de afiliación:
Italia