Alu Elements and Human Disease
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Date
2007-06
Authors
Belzil, Camille
Journal Title
Journal ISSN
Volume Title
Publisher
Lethbridge Undergraduate Research Journal
Abstract
As a family, Alu retrotransposons compose the single largest component of
the human genome [2]. They are thought to have arisen from the gene
coding for 7SL RNA, a component of the signal recognition particle [14, 19,
23]. The only apparent purpose of these highly repetitive sequences is to
replicate and copy themselves onto new areas of the genome; this has
resulted in an estimated 10% growth in human genome size since our
evolutionary divergence with the chimpanzee [2]. Normally cellular proteins
methylate the cytosine and guanine rich areas of these transcripts in order
to prevent the retrotransposon from displacing. When cellular conditions
promote demethylation, Alu regions can be transcribed and insert into new
areas of the genome via an RNA intermediate [2]. Insertion into a noncoding
region is typically harmless, but introduction into a coding exon can lead to disrupted gene transcription and altered protein synthesis. The
original demethylation event is largely a result of environmental conditions
and leads to heritable changes in DNA sequence [22]. It is estimated that
Alu retrotransposition currently occurs at a rate of about 1 per every 200
births, and alone accounts for an estimated 0.1% of genetic disorders [8].
The recombination of Alu elements could potentially be one of the most
important sources of genetic variation, but is also a major source of human
genetic disease.
Description
Keywords
Genetic disorders--Molecular aspects , Gene mapping
Citation
Belzil, Camille (2007). Alu Elements and Human Disease. Lethbridge Undergraduate Research Journal, 2(1).