Distribution of segmental duplications in the context of higher order chromatin organisation of human chromosome 7

TY - JOUR

T1 - Distribution of segmental duplications in the context of higher order chromatin organisation of human chromosome 7

AU - Ebert, Grit

AU - Steininger, Anne

AU - Weißmann, Robert

AU - Boldt, Vivien

AU - Lind-Thomsen, Allan

AU - Grune, Jana

AU - Badelt, Stefan

AU - Heßler, Melanie

AU - Peiser, Matthias

AU - Hitzler, Manuel

AU - Jensen, Lars R

AU - Müller, Ines

AU - Hu, Hao

AU - Arndt, Peter F

AU - Kuss, Andreas W

AU - Tebel, Katrin

AU - Ullmann, Reinhard

PY - 2014/6/29

Y1 - 2014/6/29

N2 - BACKGROUND: Segmental duplications (SDs) are not evenly distributed along chromosomes. The reasons for this biased susceptibility to SD insertion are poorly understood. Accumulation of SDs is associated with increased genomic instability, which can lead to structural variants and genomic disorders such as the Williams-Beuren syndrome. Despite these adverse effects, SDs have become fixed in the human genome. Focusing on chromosome 7, which is particularly rich in interstitial SDs, we have investigated the distribution of SDs in the context of evolution and the three dimensional organisation of the chromosome in order to gain insights into the mutual relationship of SDs and chromatin topology.RESULTS: Intrachromosomal SDs preferentially accumulate in those segments of chromosome 7 that are homologous to marmoset chromosome 2. Although this formerly compact segment has been re-distributed to three different sites during primate evolution, we can show by means of public data on long distance chromatin interactions that these three intervals, and consequently the paralogous SDs mapping to them, have retained their spatial proximity in the nucleus. Focusing on SD clusters implicated in the aetiology of the Williams-Beuren syndrome locus we demonstrate by cross-species comparison that these SDs have inserted at the borders of a topological domain and that they flank regions with distinct DNA conformation.CONCLUSIONS: Our study suggests a link of nuclear architecture and the propagation of SDs across chromosome 7, either by promoting regional SD insertion or by contributing to the establishment of higher order chromatin organisation themselves. The latter could compensate for the high risk of structural rearrangements and thus may have contributed to their evolutionary fixation in the human genome.

AB - BACKGROUND: Segmental duplications (SDs) are not evenly distributed along chromosomes. The reasons for this biased susceptibility to SD insertion are poorly understood. Accumulation of SDs is associated with increased genomic instability, which can lead to structural variants and genomic disorders such as the Williams-Beuren syndrome. Despite these adverse effects, SDs have become fixed in the human genome. Focusing on chromosome 7, which is particularly rich in interstitial SDs, we have investigated the distribution of SDs in the context of evolution and the three dimensional organisation of the chromosome in order to gain insights into the mutual relationship of SDs and chromatin topology.RESULTS: Intrachromosomal SDs preferentially accumulate in those segments of chromosome 7 that are homologous to marmoset chromosome 2. Although this formerly compact segment has been re-distributed to three different sites during primate evolution, we can show by means of public data on long distance chromatin interactions that these three intervals, and consequently the paralogous SDs mapping to them, have retained their spatial proximity in the nucleus. Focusing on SD clusters implicated in the aetiology of the Williams-Beuren syndrome locus we demonstrate by cross-species comparison that these SDs have inserted at the borders of a topological domain and that they flank regions with distinct DNA conformation.CONCLUSIONS: Our study suggests a link of nuclear architecture and the propagation of SDs across chromosome 7, either by promoting regional SD insertion or by contributing to the establishment of higher order chromatin organisation themselves. The latter could compensate for the high risk of structural rearrangements and thus may have contributed to their evolutionary fixation in the human genome.

U2 - 10.1186/1471-2164-15-537

DO - 10.1186/1471-2164-15-537

M3 - Journal article

C2 - 24973960

SN - 1471-2164

VL - 15

SP - 1

EP - 17

JO - BMC Genomics

JF - BMC Genomics

IS - 1

M1 - 537

ER -