Alu elements in primates are preferentially lost from areas of high GC content

The currently-accepted dogma when analysing human Alu transposable elements is that ‘young’ Alu elements are found in low GC regions and ‘old’ Alus in high GC regions. The correlation between high GC regions and high gene frequency regions make this observation particularly difficult to explain. Alt...

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Main Authors: Elizabeth HB Hellen, John FY Brookfield
Format: Article
Language:English
Published: PeerJ Inc. 2013-05-01
Series:PeerJ
Subjects:
Online Access:https://peerj.com/articles/78.pdf
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author Elizabeth HB Hellen
John FY Brookfield
author_facet Elizabeth HB Hellen
John FY Brookfield
author_sort Elizabeth HB Hellen
collection DOAJ
description The currently-accepted dogma when analysing human Alu transposable elements is that ‘young’ Alu elements are found in low GC regions and ‘old’ Alus in high GC regions. The correlation between high GC regions and high gene frequency regions make this observation particularly difficult to explain. Although a number of studies have tackled the problem, no analysis has definitively explained the reason for this trend. These observations have been made by relying on the subfamily as a proxy for age of an element. In this study, we suggest that this is a misleading assumption and instead analyse the relationship between the taxonomic distribution of an individual element and its surrounding GC environment. An analysis of 103906 Alu elements across 6 human chromosomes was carried out, using the presence of orthologous Alu elements in other primate species as a proxy for age. We show that the previously-reported effect of GC content correlating with subfamily age is not reflected by the ages of the individual elements. Instead, elements are preferentially lost from areas of high GC content over time. The correlation between GC content and subfamily may be due to a change in insertion bias in the young subfamilies. The link between Alu subfamily age and GC region was made due to an over-simplification of the data and is incorrect. We suggest that use of subfamilies as a proxy for age is inappropriate and that the analysis of ortholog presence in other primate species provides a deeper insight into the data.
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spelling doaj.art-9d3157aecff64ca0a5aa3e9f9bb72f212023-12-03T10:22:41ZengPeerJ Inc.PeerJ2167-83592013-05-011e7810.7717/peerj.7878Alu elements in primates are preferentially lost from areas of high GC contentElizabeth HB Hellen0John FY Brookfield1Centre for Genetics and Genomics, School of Biology, University of Nottingham, University Park, Nottingham, UKCentre for Genetics and Genomics, School of Biology, University of Nottingham, University Park, Nottingham, UKThe currently-accepted dogma when analysing human Alu transposable elements is that ‘young’ Alu elements are found in low GC regions and ‘old’ Alus in high GC regions. The correlation between high GC regions and high gene frequency regions make this observation particularly difficult to explain. Although a number of studies have tackled the problem, no analysis has definitively explained the reason for this trend. These observations have been made by relying on the subfamily as a proxy for age of an element. In this study, we suggest that this is a misleading assumption and instead analyse the relationship between the taxonomic distribution of an individual element and its surrounding GC environment. An analysis of 103906 Alu elements across 6 human chromosomes was carried out, using the presence of orthologous Alu elements in other primate species as a proxy for age. We show that the previously-reported effect of GC content correlating with subfamily age is not reflected by the ages of the individual elements. Instead, elements are preferentially lost from areas of high GC content over time. The correlation between GC content and subfamily may be due to a change in insertion bias in the young subfamilies. The link between Alu subfamily age and GC region was made due to an over-simplification of the data and is incorrect. We suggest that use of subfamilies as a proxy for age is inappropriate and that the analysis of ortholog presence in other primate species provides a deeper insight into the data.https://peerj.com/articles/78.pdfTransposonsAluYoungOldGC contentInsertion bias
spellingShingle Elizabeth HB Hellen
John FY Brookfield
Alu elements in primates are preferentially lost from areas of high GC content
PeerJ
Transposons
Alu
Young
Old
GC content
Insertion bias
title Alu elements in primates are preferentially lost from areas of high GC content
title_full Alu elements in primates are preferentially lost from areas of high GC content
title_fullStr Alu elements in primates are preferentially lost from areas of high GC content
title_full_unstemmed Alu elements in primates are preferentially lost from areas of high GC content
title_short Alu elements in primates are preferentially lost from areas of high GC content
title_sort alu elements in primates are preferentially lost from areas of high gc content
topic Transposons
Alu
Young
Old
GC content
Insertion bias
url https://peerj.com/articles/78.pdf
work_keys_str_mv AT elizabethhbhellen aluelementsinprimatesarepreferentiallylostfromareasofhighgccontent
AT johnfybrookfield aluelementsinprimatesarepreferentiallylostfromareasofhighgccontent