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Updated: Jul 10, 2026
08:27
A Non-random Mouse Model for Pharmacological Reactivation of Mecp2 on the Inactive X Chromosome
Published on: May 22, 2019
A recurrent inversion on the eutherian X chromosome.
Mario Cáceres1, , Robert T Sullivan
1Genes and Disease Program, Center for Genomic Regulation, 08003 Barcelona, Spain.
Summary
Chromosomal inversions are key to evolution. A specific human Xq28 inversion, involving FLNA and EMD genes, has repeatedly occurred across eutherian mammal evolution due to ancient duplications.
Area of Science:
- Genomics
- Evolutionary Biology
- Comparative Genomics
Background:
- Chromosomal inversions play a significant role in evolution.
- Polymorphic inversions are increasingly identified in human populations.
- Understanding inversion mechanisms and evolutionary history is crucial.
Purpose of the Study:
- To investigate the evolutionary history of a specific polymorphic inversion on human chromosome Xq28.
- To determine if this inversion is unique to humans or a recurrent event in other species.
- To elucidate the mechanisms driving the formation and recurrence of this inversion.
Main Methods:
- Comparative genomic analysis of the orthologous region in 27 eutherian species.
- In-depth sequence analysis of flanking inverted duplications.
- Phylogenetic analysis to trace the origin and recurrence of the inversion.
Main Results:
- The Xq28 inversion is not human-specific but has occurred independently at least 10 times in multiple eutherian lineages.
- Inverted duplications flanking the FLNA-EMD region are conserved across eutherian species.
- A model proposing a common ancestral duplication event followed by gene conversion and nonallelic homologous recombination (NAHR) was developed.
Conclusions:
- The recurrent inversion of the Xq28 segment is driven by ancient, homogenized inverted duplications acting as substrates for NAHR.
- This study provides strong evidence for the evolutionary breakpoint reusage hypothesis.
- Near-identical human segmental duplications may have origins exceeding 100 million years.
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