3D genome evolution and reorganization in the Drosophila melanogaster species group.

Topologically associating domains, or TADs, are functional units that organize chromosomes into 3D structures of interacting chromatin. TADs play an important role in regulating gene expression by constraining enhancer-promoter contacts and there is evidence that deletion of TAD boundaries leads to...

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Main Authors: Nicole S Torosin, Aparna Anand, Tirupathi Rao Golla, Weihuan Cao, Christopher E Ellison
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2020-12-01
Series:PLoS Genetics
Online Access:https://doi.org/10.1371/journal.pgen.1009229
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author Nicole S Torosin
Aparna Anand
Tirupathi Rao Golla
Weihuan Cao
Christopher E Ellison
author_facet Nicole S Torosin
Aparna Anand
Tirupathi Rao Golla
Weihuan Cao
Christopher E Ellison
author_sort Nicole S Torosin
collection DOAJ
description Topologically associating domains, or TADs, are functional units that organize chromosomes into 3D structures of interacting chromatin. TADs play an important role in regulating gene expression by constraining enhancer-promoter contacts and there is evidence that deletion of TAD boundaries leads to aberrant expression of neighboring genes. While the mechanisms of TAD formation have been well-studied, current knowledge on the patterns of TAD evolution across species is limited. Due to the integral role TADs play in gene regulation, their structure and organization is expected to be conserved during evolution. However, more recent research suggests that TAD structures diverge relatively rapidly. We use Hi-C chromosome conformation capture to measure evolutionary conservation of whole TADs and TAD boundary elements between D. melanogaster and D. triauraria, two early-branching species from the melanogaster species group which diverged ∼15 million years ago. We find that the majority of TADs have been reorganized since the common ancestor of D. melanogaster and D. triauraria, via a combination of chromosomal rearrangements and gain/loss of TAD boundaries. TAD reorganization between these two species is associated with a localized effect on gene expression, near the site of disruption. By separating TADs into subtypes based on their chromatin state, we find that different subtypes are evolving under different evolutionary forces. TADs enriched for broadly expressed, transcriptionally active genes are evolving rapidly, potentially due to positive selection, whereas TADs enriched for developmentally-regulated genes remain conserved, presumably due to their importance in restricting gene-regulatory element interactions. These results provide novel insight into the evolutionary dynamics of TADs and help to reconcile contradictory reports related to the evolutionary conservation of TADs and whether changes in TAD structure affect gene expression.
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spelling doaj.art-7744f5f32f324fbbb3d49a28fd9354242022-12-21T20:06:50ZengPublic Library of Science (PLoS)PLoS Genetics1553-73901553-74042020-12-011612e100922910.1371/journal.pgen.10092293D genome evolution and reorganization in the Drosophila melanogaster species group.Nicole S TorosinAparna AnandTirupathi Rao GollaWeihuan CaoChristopher E EllisonTopologically associating domains, or TADs, are functional units that organize chromosomes into 3D structures of interacting chromatin. TADs play an important role in regulating gene expression by constraining enhancer-promoter contacts and there is evidence that deletion of TAD boundaries leads to aberrant expression of neighboring genes. While the mechanisms of TAD formation have been well-studied, current knowledge on the patterns of TAD evolution across species is limited. Due to the integral role TADs play in gene regulation, their structure and organization is expected to be conserved during evolution. However, more recent research suggests that TAD structures diverge relatively rapidly. We use Hi-C chromosome conformation capture to measure evolutionary conservation of whole TADs and TAD boundary elements between D. melanogaster and D. triauraria, two early-branching species from the melanogaster species group which diverged ∼15 million years ago. We find that the majority of TADs have been reorganized since the common ancestor of D. melanogaster and D. triauraria, via a combination of chromosomal rearrangements and gain/loss of TAD boundaries. TAD reorganization between these two species is associated with a localized effect on gene expression, near the site of disruption. By separating TADs into subtypes based on their chromatin state, we find that different subtypes are evolving under different evolutionary forces. TADs enriched for broadly expressed, transcriptionally active genes are evolving rapidly, potentially due to positive selection, whereas TADs enriched for developmentally-regulated genes remain conserved, presumably due to their importance in restricting gene-regulatory element interactions. These results provide novel insight into the evolutionary dynamics of TADs and help to reconcile contradictory reports related to the evolutionary conservation of TADs and whether changes in TAD structure affect gene expression.https://doi.org/10.1371/journal.pgen.1009229
spellingShingle Nicole S Torosin
Aparna Anand
Tirupathi Rao Golla
Weihuan Cao
Christopher E Ellison
3D genome evolution and reorganization in the Drosophila melanogaster species group.
PLoS Genetics
title 3D genome evolution and reorganization in the Drosophila melanogaster species group.
title_full 3D genome evolution and reorganization in the Drosophila melanogaster species group.
title_fullStr 3D genome evolution and reorganization in the Drosophila melanogaster species group.
title_full_unstemmed 3D genome evolution and reorganization in the Drosophila melanogaster species group.
title_short 3D genome evolution and reorganization in the Drosophila melanogaster species group.
title_sort 3d genome evolution and reorganization in the drosophila melanogaster species group
url https://doi.org/10.1371/journal.pgen.1009229
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