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Lactase persistence in Tunisia as a result of admixture with other Mediterranean populations

BACKGROUND: The ability to digest lactose after weaning, namely, lactase persistence (LP), is encoded by polymorphisms in the MCM6 gene and varies widely in frequency among different human populations. Although, evolution of LP-related genetic variants was investigated in many groups of Sub-Saharan...

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Autores principales: Ben Halima, Yosra, Kefi, Rym, Sazzini, Marco, Giuliani, Cristina, De Fanti, Sara, Nouali, Chokri, Nagara, Majdi, Mengozzi, Giacomo, Elouej, Sahar, Abid, Abdelmajid, Jamoussi, Henda, Chouchane, Lotfi, Romeo, Giovanni, Abdelhak, Sonia, Luiselli, Donata
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571577/
https://www.ncbi.nlm.nih.gov/pubmed/28855970
http://dx.doi.org/10.1186/s12263-017-0573-3
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author Ben Halima, Yosra
Kefi, Rym
Sazzini, Marco
Giuliani, Cristina
De Fanti, Sara
Nouali, Chokri
Nagara, Majdi
Mengozzi, Giacomo
Elouej, Sahar
Abid, Abdelmajid
Jamoussi, Henda
Chouchane, Lotfi
Romeo, Giovanni
Abdelhak, Sonia
Luiselli, Donata
author_facet Ben Halima, Yosra
Kefi, Rym
Sazzini, Marco
Giuliani, Cristina
De Fanti, Sara
Nouali, Chokri
Nagara, Majdi
Mengozzi, Giacomo
Elouej, Sahar
Abid, Abdelmajid
Jamoussi, Henda
Chouchane, Lotfi
Romeo, Giovanni
Abdelhak, Sonia
Luiselli, Donata
author_sort Ben Halima, Yosra
collection PubMed
description BACKGROUND: The ability to digest lactose after weaning, namely, lactase persistence (LP), is encoded by polymorphisms in the MCM6 gene and varies widely in frequency among different human populations. Although, evolution of LP-related genetic variants was investigated in many groups of Sub-Saharan African, Middle Eastern, and European ancestry, only few studies have focused on populations from North Africa and no data are especially available from the Tunisian one. For this reason, there is an urgent need to investigate the frequency patterns at these loci in Tunisia since this adaptive trait is implicated in health. METHODS: Forty SNPs covering the LCT/MCM6 genes and including the two functional variants − 13,910 C > T and − 22,018 G > A were genotyped in 117 Tunisian individuals using the Sequenom Mass Array technology. The observed nucleotide and haplotype patterns of variation were then compared with those of several African, European, and Mediterranean human groups for which comparable data were publicly available. Admixture analysis on a 5 Mb genomic region surrounding the LCT/MCM6 loci was also performed by extracting genotypes from a previously generated genome-wide dataset in order to deepen the reconstruction of the evolutionary history of these loci. RESULTS: We found that lactase non-persistence (LNP)-related alleles and haplotypes were predominantly present in the examined population. A clear differentiation between Tunisian, African, and North European/North Italian samples was found, while the Tunisian population showed more genetic affinity to Central and South Italian groups. CONCLUSIONS: Our study provided a first report of LP-associated alleles and haplotypes in the Tunisian population. We highlighted a gradient followed by LP diffusion from Europe to North Africa. Based on the rich historic background of Tunisia, we suggest that this adaptive trait was introduced in that geographic region by a relatively recent gene flow. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12263-017-0573-3) contains supplementary material, which is available to authorized users.
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spelling pubmed-55715772017-08-30 Lactase persistence in Tunisia as a result of admixture with other Mediterranean populations Ben Halima, Yosra Kefi, Rym Sazzini, Marco Giuliani, Cristina De Fanti, Sara Nouali, Chokri Nagara, Majdi Mengozzi, Giacomo Elouej, Sahar Abid, Abdelmajid Jamoussi, Henda Chouchane, Lotfi Romeo, Giovanni Abdelhak, Sonia Luiselli, Donata Genes Nutr Research BACKGROUND: The ability to digest lactose after weaning, namely, lactase persistence (LP), is encoded by polymorphisms in the MCM6 gene and varies widely in frequency among different human populations. Although, evolution of LP-related genetic variants was investigated in many groups of Sub-Saharan African, Middle Eastern, and European ancestry, only few studies have focused on populations from North Africa and no data are especially available from the Tunisian one. For this reason, there is an urgent need to investigate the frequency patterns at these loci in Tunisia since this adaptive trait is implicated in health. METHODS: Forty SNPs covering the LCT/MCM6 genes and including the two functional variants − 13,910 C > T and − 22,018 G > A were genotyped in 117 Tunisian individuals using the Sequenom Mass Array technology. The observed nucleotide and haplotype patterns of variation were then compared with those of several African, European, and Mediterranean human groups for which comparable data were publicly available. Admixture analysis on a 5 Mb genomic region surrounding the LCT/MCM6 loci was also performed by extracting genotypes from a previously generated genome-wide dataset in order to deepen the reconstruction of the evolutionary history of these loci. RESULTS: We found that lactase non-persistence (LNP)-related alleles and haplotypes were predominantly present in the examined population. A clear differentiation between Tunisian, African, and North European/North Italian samples was found, while the Tunisian population showed more genetic affinity to Central and South Italian groups. CONCLUSIONS: Our study provided a first report of LP-associated alleles and haplotypes in the Tunisian population. We highlighted a gradient followed by LP diffusion from Europe to North Africa. Based on the rich historic background of Tunisia, we suggest that this adaptive trait was introduced in that geographic region by a relatively recent gene flow. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12263-017-0573-3) contains supplementary material, which is available to authorized users. BioMed Central 2017-08-24 /pmc/articles/PMC5571577/ /pubmed/28855970 http://dx.doi.org/10.1186/s12263-017-0573-3 Text en © The Author(s) 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Ben Halima, Yosra
Kefi, Rym
Sazzini, Marco
Giuliani, Cristina
De Fanti, Sara
Nouali, Chokri
Nagara, Majdi
Mengozzi, Giacomo
Elouej, Sahar
Abid, Abdelmajid
Jamoussi, Henda
Chouchane, Lotfi
Romeo, Giovanni
Abdelhak, Sonia
Luiselli, Donata
Lactase persistence in Tunisia as a result of admixture with other Mediterranean populations
title Lactase persistence in Tunisia as a result of admixture with other Mediterranean populations
title_full Lactase persistence in Tunisia as a result of admixture with other Mediterranean populations
title_fullStr Lactase persistence in Tunisia as a result of admixture with other Mediterranean populations
title_full_unstemmed Lactase persistence in Tunisia as a result of admixture with other Mediterranean populations
title_short Lactase persistence in Tunisia as a result of admixture with other Mediterranean populations
title_sort lactase persistence in tunisia as a result of admixture with other mediterranean populations
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571577/
https://www.ncbi.nlm.nih.gov/pubmed/28855970
http://dx.doi.org/10.1186/s12263-017-0573-3
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