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Evolutionary analysis of the highly dynamic CHEK2 duplicon in anthropoids
Claudia Münch1, Stefan Kirsch, António M G Fernandes
1Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str, 33, 79106 Freiburg, Germany. claudia.muench@uniklinik-freiburg.de
BMC Evolutionary Biology
|October 4, 2008
Summary
Segmental duplications (SDs) of the CHEK2 gene, a cancer susceptibility gene, expanded significantly in African great apes and humans. Humans exhibit the highest CHEK2 copy number, indicating dynamic gene evolution and potential diagnostic challenges.
Area of Science:
- Genomics
- Evolutionary Biology
- Molecular Biology
Background:
- Segmental duplications (SDs) are large genomic regions (>1kb) with high sequence identity, comprising ~5% of the human genome.
- CHEK2 is a crucial cell cycle checkpoint kinase involved in DNA damage response and cancer susceptibility.
- Investigating CHEK2 duplications offers insights into gene evolution and genome stability.
Purpose of the Study:
- To investigate the evolutionary history and phylogenetic patterns of CHEK2 duplications in anthropoids.
- To determine the timing and extent of CHEK2 gene duplication events during primate evolution.
- To assess the impact of segmental duplications on CHEK2 copy number variation.
Main Methods:
- Comparative fluorescence in situ hybridization (FISH) to map CHEK2 loci across primate species.
- In silico analyses to study paralogous and ancestral CHEK2 sequences.
- Inter-species quantitative PCR (qPCR) to quantify CHEK2 gene copy numbers.
Main Results:
- CHEK2 is single-copy in New World monkeys, Old World monkeys, and gibbons.
- A duplication event occurred in orangutans, followed by a burst of duplications in African great apes and humans.
- Humans possess the highest CHEK2 copy number among the studied species, with observed intra-human variation.
Conclusions:
- CHEK2 duplication is a dynamic process during anthropoid evolution, with a significant expansion after orangutan and African ape radiation.
- Segmental duplications contribute to inter-species genomic variation.
- CHEK2 copy number variation in humans may complicate molecular diagnostics for cancer susceptibility.
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