TY - JOUR

T1 - The dispersal of ribosomal gene sequences in the karyotype of Coturnix japonica

AU - Saifitdinova , A.

AU - Galkina , S.

AU - Kulak , M.

AU - Fillon, Valerie

AU - Volodkina , V.

AU - Pavlova, O.

AU - Gaginskaya, E.R.

N1 - Publisher Copyright: © 2019, National Academy of Sciences of Ukraine. All rights reserved.

PY - 2019/5/20

Y1 - 2019/5/20

N2 - Numerous copies of rDNA genes form nucleolar organizer regions (NORs) on chromosome and give rise to the interphase nucleoli. Bird species commonly have a single pair of the NOR bearing chromosomes in the karyotype (Schmid et al., 1982). Japanese quail is an exception and has three pairs of chromosomes with active NOR (McPherson et al., 2014). Even within a single NOR array individual sequences may differ (Kim et al., 2018). This work was aimed at studying the individual sequences that make up different NORs in Coturnix japonica. Methods: Using primers to the conserved region of the 18S ribosomal RNA gene, we amplified rDNA the range of fragments from the quail genome karyotype. The rDNA fragments were cloned, sequenced, analyzed bioinformatically and mapped by FISH. Results: Ribosomal gene derivatives were found to localize on the short heterochro-matic arms of all acrocentric chromosomes in the complement. In addition to functional NOR sequences, we have found chimeric sequences containing fragments of transposable elements, fragments of MHC genes and some others. As it was shown earlier active transcription makes NOR a target for transposons and causes mutual amplification of the chimeric sequences of transposons and ribosomal genes (Buzdin et al., 2007). Conclusions: In the genome of Japanese quail transposition of NOR sequences apparently led to the dispersal and amplification of NORs, three of which retained their functionality.

AB - Numerous copies of rDNA genes form nucleolar organizer regions (NORs) on chromosome and give rise to the interphase nucleoli. Bird species commonly have a single pair of the NOR bearing chromosomes in the karyotype (Schmid et al., 1982). Japanese quail is an exception and has three pairs of chromosomes with active NOR (McPherson et al., 2014). Even within a single NOR array individual sequences may differ (Kim et al., 2018). This work was aimed at studying the individual sequences that make up different NORs in Coturnix japonica. Methods: Using primers to the conserved region of the 18S ribosomal RNA gene, we amplified rDNA the range of fragments from the quail genome karyotype. The rDNA fragments were cloned, sequenced, analyzed bioinformatically and mapped by FISH. Results: Ribosomal gene derivatives were found to localize on the short heterochro-matic arms of all acrocentric chromosomes in the complement. In addition to functional NOR sequences, we have found chimeric sequences containing fragments of transposable elements, fragments of MHC genes and some others. As it was shown earlier active transcription makes NOR a target for transposons and causes mutual amplification of the chimeric sequences of transposons and ribosomal genes (Buzdin et al., 2007). Conclusions: In the genome of Japanese quail transposition of NOR sequences apparently led to the dispersal and amplification of NORs, three of which retained their functionality.

UR - http://www.scopus.com/inward/record.url?scp=85077072165&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/dispersal-ribosomal-gene-sequences-karyotype-coturnix-japonica

U2 - 10.7124/bc.0009F5

DO - 10.7124/bc.0009F5

M3 - Article

VL - 35

SP - 229

EP - 230

JO - Biopolymers and Cell

JF - Biopolymers and Cell

SN - 0233-7657

IS - 3

ER -