Evolutionarily Conserved Noncoding DNA in the Human Genome: How Much and What For?
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan 48109-0618, USA
This extract was created in the absence of an abstract.
The noncoding component of the human genome is receiving increased attention from biologists because of its predicted role in regulation of transcription, DNA replication, chromosome pairing, and chromosome condensation. Finding the functional elements within this 97% of the human genome presents major intellectual and experimental challenges. By comparing genomic DNA sequence from diverse species, functional elements may be recognized on the basis of their evolutionary conservation. In this issue, Frazer et al. (2001) describe the large-scale identification of conserved noncoding elements from human chromosome 21 using oligonucleotide array technology. In a two-way comparison between mouse and human, they found that the amount of conserved noncoding sequence was roughly equal to the coding sequence in this region. One-half of the human/mouse conserved noncoding sequence was also conserved in a third mammal, the dog. This work produced a catalog of potential functional elements for chromosome 21 that will be valuable to future studies of gene regulation and chromosome mechanics. In addition, a method for identification of conserved sequences prior to genome sequencing is shown.
Background
Evolutionary comparisons have been performed since the earliest days of cloning and sequencing of mammalian DNA (Table1). One of the first examples was the identification of short, highly conserved noncoding regions in the cloned human and mouse immunoglobin genes by detection of heteroduplex molecules …
