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Am J Phys Anthropol. 2015 Dec;158(4):708-18. doi: 10.1002/ajpa.22814. Epub 2015 Jul 15.

Inferring the genetic history of lactase persistence along the Italian peninsula from a large genomic interval surrounding the LCT gene.

Author information

1
Laboratory of Molecular Anthropology, Department of Biological, Geological and Environmental Sciences (BiGeA), University of Bologna, Bologna, 40126, Italy.
2
Department of Biological, Geological and Environmental Sciences (BiGeA), Centre for Genome Biology, University of Bologna, Bologna, 40126, Italy.
3
Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Bologna, 40126, Italy.
4
Center for Applied Biomedical Research (CRBA), St. Orsola-Malpighi University Hospital, Bologna, 40138, Italy.
5
Department of Animal Biology-Anthropology, University of Barcelona, Barcelona, 08028, Spain.

Abstract

OBJECTIVE:

Although genetic variants related to lactase persistence in European populations were supposed to have firstly undergone positive selection in farmers from the Balkans and Central Europe, demographic and evolutionary dynamics that subsequently shaped the distribution of this adaptive trait across the continent have still to be elucidated. To deepen the knowledge about potential routes of diffusion of lactase persistence to Western Europe we investigated variation at a large genomic region surrounding the LCT gene along the Italian peninsula, a geographical area that played a key role in population movements responsible for Neolithic diffusion across Europe.

METHODS:

By genotyping 40 highly selected SNPs in more than 400 Italian individuals we described gradients of nucleotide and haplotype variation potentially related to lactase persistence and compared them with those observed in several European and Mediterranean human groups.

RESULTS:

Multiple migratory events responsible for earlier introduction of the examined alleles in Italy than in Northern European regions could be invoked. Different demic processes occurred along the western and eastern sides of the peninsula were also inferred via linkage disequilibrium and population structure analyses.

CONCLUSION:

The appreciable genetic continuum observed between people from Northern or Central-Western Italy and Central European populations suggested a local arrival of lactase persistence-related variants mainly via overland routes. On the contrary, diversity of Central-Eastern and Southern Italian groups entailed also gene flow from South-Eastern Mediterranean regions, in accordance to the earlier entrance of the Neolithic in Southern Italy via maritime population movements along the Mediterranean coastlines.

KEYWORDS:

Mediterranean human populations; anthropological genetics; lactose tolerance; natural selection

PMID:
26175013
DOI:
10.1002/ajpa.22814
[Indexed for MEDLINE]

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