TY - JOUR

T1 - The case of X and Y localization of nucleolus organizer regions (NORs) in tragulus javanicus (Cetartiodactyla, Mammalia)

AU - Proskuryakova, Anastasia A.

AU - Kulemzina, Anastasia I.

AU - Perelman, Polina L.

AU - Serdukova, Natalia A.

AU - Ryder, Oliver A.

AU - Graphodatsky, Alexander S.

N1 - Publisher Copyright: © 2018 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2018/6/20

Y1 - 2018/6/20

N2 - There are differences in number and localization of nucleolus organizer regions (NORs) in genomes. In mammalian genomes, NORs are located on autosomes, which are often situated on short arms of acrocentric chromosomes and more rarely in telomeric, pericentromeric, or interstitial regions. In this work, we report the unique case of active NORs located on gonоsomes of a eutherian mammal, the Javan mouse-deer (Tragulus javanicus). We have investigated the position of NORs by FISH experiments with ribosomal DNA (rDNA) sequences (18S, 5.8S, and 28S) and show the presence of a single NOR site on the X and Y chromosomes. The NOR is localized interstitially on the p-arm of the X chromosome in close proximity with prominent C-positive heterochromatin blocks and in the pericentromeric area of mostly heterochromatic Y. The NOR sites are active on both the X and Y chromosomes in the studied individual and surrounded by GC enriched heterochromatin. We hypothesize that the surrounding heterochromatin might have played a role in the transfer of NORs from autosomes to sex chromosomes during the karyotype evolution of the Javan mouse-deer.

AB - There are differences in number and localization of nucleolus organizer regions (NORs) in genomes. In mammalian genomes, NORs are located on autosomes, which are often situated on short arms of acrocentric chromosomes and more rarely in telomeric, pericentromeric, or interstitial regions. In this work, we report the unique case of active NORs located on gonоsomes of a eutherian mammal, the Javan mouse-deer (Tragulus javanicus). We have investigated the position of NORs by FISH experiments with ribosomal DNA (rDNA) sequences (18S, 5.8S, and 28S) and show the presence of a single NOR site on the X and Y chromosomes. The NOR is localized interstitially on the p-arm of the X chromosome in close proximity with prominent C-positive heterochromatin blocks and in the pericentromeric area of mostly heterochromatic Y. The NOR sites are active on both the X and Y chromosomes in the studied individual and surrounded by GC enriched heterochromatin. We hypothesize that the surrounding heterochromatin might have played a role in the transfer of NORs from autosomes to sex chromosomes during the karyotype evolution of the Javan mouse-deer.

KW - Chevrotain

KW - Chromosome evolution

KW - Genome

KW - Karyotype

KW - Ribosomal DNA

KW - Sex chromosomes

KW - LOCATION

KW - chevrotain

KW - RECOMBINATION

KW - CHARACIFORMES

KW - ribosomal DNA

KW - chromosome evolution

KW - sex chromosomes

KW - RIBOSOMAL-RNA GENES

KW - PRIMATES

KW - CHROMOSOME EVOLUTION

KW - genome

KW - karyotype

KW - DNA

KW - ARTIODACTYLA

KW - DYNAMICS

KW - KARYOTYPIC ANALYSIS

UR - http://www.scopus.com/inward/record.url?scp=85048811302&partnerID=8YFLogxK

U2 - 10.3390/genes9060312

DO - 10.3390/genes9060312

M3 - Article

C2 - 29925822

AN - SCOPUS:85048811302

VL - 9

JO - Genes

JF - Genes

SN - 2073-4425

IS - 6

M1 - 312

ER -