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Characterization of an evolutionarily old human alphoid DNA
S L Carnahan1, E Palamidis-Bourtsos, P R Musich
1Department of Biology, Loyola University of Chicago, IL 60626.
Gene
|January 30, 1993
Summary
A novel human alphoid DNA sequence, found in all tested primates, shows high similarity to the consensus but heterogeneous monomers. This ancient DNA is located on human chromosomes 21 and 22.
Area of Science:
- Genomics
- Molecular Biology
- Evolutionary Biology
Background:
- Alphoid DNA comprises repetitive sequences critical for centromere function.
- Previous studies focused on human-specific alphoid DNA variants.
Purpose of the Study:
- To characterize a newly isolated human alphoid DNA sequence (pHH550).
- To investigate the evolutionary conservation and chromosomal localization of this unique alphoid DNA.
Main Methods:
- DNA sequencing of plasmid pHH550.
- Comparative sequence analysis against human alphoid consensus.
- Interspecies hybridization and chromosomal mapping.
Main Results:
- The pHH550 sequence exhibits high similarity to the human alphoid consensus.
- Component monomers within pHH550 are unusually heterogeneous.
- This alphoid DNA is conserved across all tested primate species.
- pHH550 sequences are present on human chromosomes 21 and 22, often distal to other alphoid DNAs on chromosome 21.
Conclusions:
- The pHH550 sequence represents an evolutionarily ancient form of alphoid DNA.
- Its presence in all primates suggests a conserved ancestral origin predating divergence of other human alphoid DNAs.
- The unique sequence characteristics and chromosomal distribution provide insights into centromeric DNA evolution.