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Published on: July 18, 2025
Ultraconservation identifies a small subset of extremely constrained developmental enhancers
Axel Visel1, Shyam Prabhakar, Jennifer A Akiyama
1Genomics Division, MS 84-171, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Nature Genetics
|January 8, 2008
Summary
Ultraconserved genomic regions, defined by extended human-rodent sequence identity, do not show unique embryonic enhancer activity compared to other conserved elements. This suggests ultraconservation identifies a constrained, but not functionally distinct, subset of regulatory elements.
Area of Science:
- Genomics
- Evolutionary Biology
- Developmental Biology
Background:
- Extended sequence identity between human and rodent genomes (ultraconservation) suggests evolutionary or functional uniqueness.
- Cis-regulatory elements, such as enhancers, play crucial roles in gene regulation during development.
Purpose of the Study:
- To investigate whether ultraconserved human genome regions possess distinct embryonic enhancer activity compared to non-ultraconserved but highly conserved regions.
- To determine if ultraconservation is a reliable indicator of functional uniqueness in cis-regulatory elements.
Main Methods:
- Utilized a transgenic mouse assay to test the embryonic enhancer activity of 231 noncoding ultraconserved human genome regions.
- Compared enhancer activity with 206 extremely conserved human genome regions lacking ultraconservation.
Main Results:
- Developmental enhancers were found to be equally prevalent in both ultraconserved and non-ultraconserved conserved genomic regions.
- No significant difference in enhancer activity was observed between the two groups of regions.
Conclusions:
- Ultraconservation does not appear to identify a functionally unique subset of cis-regulatory elements.
- Ultraconserved regions represent a constrained set of elements, but their functional significance regarding embryonic enhancement is similar to other highly conserved regions.
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