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Published on: January 19, 2017
Rapid evolution of mouse Y centromere repeat DNA belies recent sequence stability
Mark D Pertile1, Alison N Graham, K H Andy Choo
1Murdoch Childrens Research Institute, Victoria, Australia.
Genome Research
|September 10, 2009
Summary
The mouse Y chromosome centromere (Ymin) sequence was fully characterized, revealing a unique higher-order repeat structure. This sequence is stable over generations but rapidly evolves, differing from other mouse centromeres.
Area of Science:
- Genomics
- Mammalian Genetics
- Molecular Biology
Background:
- The genome of Mus musculus (house mouse) is well-studied, yet its Y chromosome centromere sequence remained unknown.
- Centromeres are crucial for chromosome segregation, and their sequences are often species-specific and rapidly evolving.
- Understanding the mouse Y centromere is vital for this key mammalian model organism.
Purpose of the Study:
- To perform the complete molecular characterization of the house mouse (Mus musculus) Y chromosome centromere.
- To investigate the sequence organization, stability, and evolutionary dynamics of the mouse Y centromere.
- To compare the evolutionary trajectory of the mouse Y centromere with that of primates.
Main Methods:
- Molecular characterization of the C57BL/6J chromosome Y centromere using BAC cloning.
- Analysis of higher-order repeat (HOR) sequence organization.
- Exploitation of patrilineal Y chromosome inheritance to assess DNA structure stability over generations.
- Comparative sequence analysis with human and chimpanzee centromeres.
Main Results:
- The mouse Y centromere comprises a novel, highly diverged minor satellite-like sequence (Ymin) with a unique HOR organization.
- The Ymin array is approximately 90 kb and was sequenced from a single BAC clone, providing the first endogenous centromere sequence.
- The Y centromere DNA structure is stable over at least 175 inbred generations.
- Despite stability, unequal genetic exchange events have altered Ymin HOR structure since subspecies divergence, driving rapid sequence evolution.
- Primate Y centromeres also show rapid divergence, suggesting convergent evolution.
Conclusions:
- The mouse Y centromere possesses a unique DNA sequence and organizational architecture, distinct from all other mouse centromeres.
- Its rapid evolution, driven by HOR turnover, parallels that observed in primate Y centromeres.
- This study provides the first complete molecular characterization of the mouse Y centromere, revealing its independent evolutionary path.
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