Centromere repositioning explains fundamental number variability in the New World monkey genus Saimiri.
Cytogenetics has historically played a key role in research on squirrel monkey (genus Saimiri) evolutionary biology. Squirrel monkeys have a diploid number of 2n = 44, but vary in fundamental number (FN). Apparently, differences in FN have phylogenetic implications and are correlated with geographic regions. A number of hypothetical mechanisms were proposed to explain difference in FN: translocations, heterochromatin, or, most commonly, pericentric inversions. Recently, an additional mechanism, centromere repositioning, was discovered, which can alter chromosome morphology and FN. Here, we used chromosome banding, chromosome painting, and BAC-FISH to test these hypotheses. We demonstrate that centromere repositioning on chromosomes 5 and 15 is the mechanism that accounts for differences in FN. Current phylogenomic trees of platyrrhines provide a temporal framework for evolutionary new centromeres (ENC) in Saimiri. The X-chromosome ENC could be up to 15 million years (my) old that on chromosome 5 as recent as 0.3 my. The chromosome 15 ENC is intermediate, as young as 2.24 my. All ENC have abundant satellite DNAs indicating that the maturation process was fairly rapid. Callithrix jacchus was used as an outgroup for the BAC-FISH data analysis. Comparison with scaffolds from the S. boliviensis genome revealed an error in the last marmoset genome release. Future research including at the sequence level will provide better understanding of chromosome evolution in Saimiri and other platyrrhines. Probably other cases of differences in chromosome morphology and FN, both within and between taxa, will be shown to be due to centromere repositioning and not pericentric inversions.
Department of Biology, Anthropology Laboratories, University of Florence, Via del Proconsolo 12, 50122, Florence, Italy.
Giorgia
G
Chiatante
Department of Biology, University of Bari, Bari, Italy.
Oronzo
O
Capozzi
Department of General Biology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Marta
M
Svartman
Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia.
Polina
P
Perelman
Department of Biology, Anthropology Laboratories, University of Florence, Via del Proconsolo 12, 50122, Florence, Italy.
Lucy
L
Centrone
Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia.
Svetlana S
SS
Romanenko
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan.
Takafumi
T
Ishida
Department of General Biology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Mirela
M
Valeri
Frederick National Laboratory of Cancer Research, Leidos Biomedical Research, Inc, Frederick, MD, USA.
Melody E
ME
Roelke-Parker
Department of Biology, Anthropology Laboratories, University of Florence, Via del Proconsolo 12, 50122, Florence, Italy. roscoe.stanyon@unifi.it.
Roscoe
0000-0002-7229-1092
R
Stanyon
D000818:Animals; D002503:Centromere / Q000235:genetics* / Q000502:physiology; D007446:Chromosome Inversion; D020223:Chromosome Painting; D020732:Cytogenetic Analysis; D019143:Evolution, Molecular; D059785:Karyotype; D010802:Phylogeny; D012453:Saimiri / Q000235:genetics*; D014178:Translocation, Genetic
BAC-FISH; Chromosome banding; Chromosome rearrangements; Evolutionary new centromeres; Molecular cytogenetics; Phylogenomics