Post by Tukuler al~Takruri on Aug 25, 2011 19:55:07 GMT -5
Mitochondrial DNA and Y-chromosome microstructure in Tunisia
Hajer Ennafaa1,3, Rosa Fregel2,3, Houssein Khodjet-el-khil1,
Ana M González2, Hejer Abdallah El Mahmoudi1, Vicente M Cabrera2,
José M Larruga2 and Amel Benammar-Elgaaïed1
1 Department of Biology, Laboratory of Genetics, Immunology and Human
Pathology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia
2 Department of Genetics, Faculty of Biology, University of La Laguna, Tenerife, Spain
Correspondence: Dr H Ennafaa, Laboratory of Genetics, Immunology and Human
Pathology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis 2092, Tunisia.
3 These authors contributed equally to this work.
Received 9 March 2011; Revised 13 July 2011; Accepted 16 July 2011; Published online 11 August 2011.
Abstract
Mitochondrial DNA (mtDNA) and Y-chromosome variation has
been studied in Bou Omrane and Bou Saâd, two Tunisian Berber
populations. In spite of their close geographic proximity, genetic
distances between them were high and significant with both
uniparental markers. A global analysis, including all previously
studied Tunisian samples, confirmed the existence of a high
female and male population structure in this country. Analyses of
molecular variance analysis evidenced that this differentiation
was not attributable to ethnic differences. Mantel test showed
that, in all cases, Y-chromosome haplotypic distances correlated
poorly with geography, whereas after excluding the more
isolated samples of Bou Omrane and Bou Saâd, the mtDNA
pattern of variation is significantly correlated with geography.
Congruently, the Nm ratio of males versus females pointed to a
significant excess of female migration rate across localities, which
could be explained by patrilocality, a common marriage system in
rural Tunisia. In addition, it has been observed that cultural
isolation in rural communities promotes, by the effect of genetic
drift, stronger loss of diversity and larger genetic differentiation
levels than those observed in urban areas as deduced from
comparisons of their respective mean genetic diversity and their
respective mean genetic distances among populations. It is likely
that the permanent exodus from rural to urban areas will have
important repercussions in the future genetic structure of this
country.
Keywords: berber; Nm ratio; North Africa; patrilocality; uniparental markers
www.nature.com/jhg/journal/vaop/ncurrent/full/jhg201192a.html
Hajer Ennafaa1,3, Rosa Fregel2,3, Houssein Khodjet-el-khil1,
Ana M González2, Hejer Abdallah El Mahmoudi1, Vicente M Cabrera2,
José M Larruga2 and Amel Benammar-Elgaaïed1
1 Department of Biology, Laboratory of Genetics, Immunology and Human
Pathology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia
2 Department of Genetics, Faculty of Biology, University of La Laguna, Tenerife, Spain
Correspondence: Dr H Ennafaa, Laboratory of Genetics, Immunology and Human
Pathology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis 2092, Tunisia.
3 These authors contributed equally to this work.
Received 9 March 2011; Revised 13 July 2011; Accepted 16 July 2011; Published online 11 August 2011.
Abstract
Mitochondrial DNA (mtDNA) and Y-chromosome variation has
been studied in Bou Omrane and Bou Saâd, two Tunisian Berber
populations. In spite of their close geographic proximity, genetic
distances between them were high and significant with both
uniparental markers. A global analysis, including all previously
studied Tunisian samples, confirmed the existence of a high
female and male population structure in this country. Analyses of
molecular variance analysis evidenced that this differentiation
was not attributable to ethnic differences. Mantel test showed
that, in all cases, Y-chromosome haplotypic distances correlated
poorly with geography, whereas after excluding the more
isolated samples of Bou Omrane and Bou Saâd, the mtDNA
pattern of variation is significantly correlated with geography.
Congruently, the Nm ratio of males versus females pointed to a
significant excess of female migration rate across localities, which
could be explained by patrilocality, a common marriage system in
rural Tunisia. In addition, it has been observed that cultural
isolation in rural communities promotes, by the effect of genetic
drift, stronger loss of diversity and larger genetic differentiation
levels than those observed in urban areas as deduced from
comparisons of their respective mean genetic diversity and their
respective mean genetic distances among populations. It is likely
that the permanent exodus from rural to urban areas will have
important repercussions in the future genetic structure of this
country.
Keywords: berber; Nm ratio; North Africa; patrilocality; uniparental markers
www.nature.com/jhg/journal/vaop/ncurrent/full/jhg201192a.html