Maps of Open Chromatin Guide the Functional Follow-Up of Genome-Wide Association Signals: Application to Hematological Traits From GWAS to Function via Maps of Open Chromatin
2011

Mapping Open Chromatin to Understand Genetic Variants in Blood Traits

Sample size: 643 publication 10 minutes Evidence: high

Author Information

Author(s): Paul Dirk S. Nisbet, James P. Yang, Stuart Meacham, Augusto Rendon, Katta Hautaviita, Jonna Tallila, Jacqui White, Marloes R. Tijssen, Suthesh Sivapalaratnam, Hanneke Basart, Mieke D. Trip, Berthold Göttgens, Nicole Soranzo, Willem H. Ouwehand, Panos Deloukas

Primary Institution: Wellcome Trust Sanger Institute

Hypothesis

Can maps of open chromatin help identify functional variants associated with hematological traits?

Conclusion

The study identified a specific genetic variant that affects platelet volume and function by altering transcription factor binding.

Supporting Evidence

  • Open chromatin profiles were distinct between megakaryocytic and erythroblastoid cells.
  • An open chromatin region at chromosome 7q22.3 was identified in megakaryocytes but not in erythroblasts.
  • Resequencing of the open chromatin region in 643 individuals provided strong evidence for the causative variant rs342293.
  • The C- and G-alleles of rs342293 differentially bind the transcription factor EVI1.
  • Gene expression analysis showed that rs342293 affects PIK3CG gene expression in platelets and macrophages.
  • Functional studies in Pik3cg knockout mice revealed significant differences in platelet-related gene expression.

Takeaway

Scientists looked at how certain parts of DNA that are open and active can help explain why some people have different blood traits. They found a specific change in DNA that affects how platelets work.

Methodology

The study used the FAIRE method to map open chromatin in megakaryocytic and erythroblastoid cell lines and analyzed genetic variants associated with hematological traits.

Limitations

The findings are based on a selected set of loci and may not be generalizable to the entire genome.

Participant Demographics

The study involved 643 individuals of Northern European ancestry.

Statistical Information

P-Value

p=0.047

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pgen.1002139

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