Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 May 1;34(5):1230-1239.
doi: 10.1093/molbev/msx082.

Mitogenome Diversity in Sardinians: A Genetic Window onto an Island's Past

Anna Olivieri  1 , Carlo Sidore  2   3   4 , Alessandro Achilli  1 , Andrea Angius  2   4   5 , Cosimo Posth  6   7 , Anja Furtwängler  7 , Stefania Brandini  1 , Marco Rosario Capodiferro  1 , Francesca Gandini  1   8 , Magdalena Zoledziewska  2 , Maristella Pitzalis  2 , Andrea Maschio  2   3 , Fabio Busonero  2   3 , Luca Lai  9 , Robin Skeates  10 , Maria Giuseppina Gradoli  11 , Jessica Beckett  12 , Michele Marongiu  2 , Vittorio Mazzarello  4 , Patrizia Marongiu  4 , Salvatore Rubino  4 , Teresa Rito  13 , Vincent Macaulay  14 , Ornella Semino  1 , Maria Pala  8 , Gonçalo R Abecasis  3 , David Schlessinger  15 , Eduardo Conde-Sousa  16 , Pedro Soares  16 , Martin B Richards  8 , Francesco Cucca  2   4 , Antonio Torroni  1
Affiliations

Mitogenome Diversity in Sardinians: A Genetic Window onto an Island's Past

Anna Olivieri et al. Mol Biol Evol. .

Abstract

Sardinians are "outliers" in the European genetic landscape and, according to paleogenomic nuclear data, the closest to early European Neolithic farmers. To learn more about their genetic ancestry, we analyzed 3,491 modern and 21 ancient mitogenomes from Sardinia. We observed that 78.4% of modern mitogenomes cluster into 89 haplogroups that most likely arose in situ. For each Sardinian-specific haplogroup (SSH), we also identified the upstream node in the phylogeny, from which non-Sardinian mitogenomes radiate. This provided minimum and maximum time estimates for the presence of each SSH on the island. In agreement with demographic evidence, almost all SSHs coalesce in the post-Nuragic, Nuragic and Neolithic-Copper Age periods. For some rare SSHs, however, we could not dismiss the possibility that they might have been on the island prior to the Neolithic, a scenario that would be in agreement with archeological evidence of a Mesolithic occupation of Sardinia.

Keywords: haplogroups; mitochondrial DNA phylogeny; mitochondrial genomes; origins of Europeans; prehistory of Sardinia.

PubMed Disclaimer

Figures

F<sc>ig</sc>. 1
Fig. 1
Schematic representation of possible scenarios (A–D) for the differentiation of a founder mtDNA haplotype into a Sardinian-Specific Haplogroup (SSH) and implications for the SSH age estimate. (A) The founder haplotype (from outside Sardinia) acquired one novel mutation (or more) in Sardinia (in situ) giving rise to the SSH. At the present time, the founder haplotype could have been lost, still be present, and/or have differentiated into a new haplotype(s) outside Sardinia. (B) The founder haplotype arrived to Sardinia and gave rise to Sardinian-specific haplotypes, but it was lost outside Sardinia. (C) The founder haplotype arrived to Sardinia and gave rise to Sardinian-specific haplotypes and is still present and/or differentiated outside Sardinia. (D) The founder haplotype diverged outside Sardinia and both the founder and the derived haplotype arrived in Sardinia where they both differentiated into Sardinian-specific haplotypes, whilst both were lost outside Sardinia. Scenarios A, B and D would give rise to what we defined as “Sardinian-specific haplogroups”, but only scenario D would lead to an overestimation of the SSH presence/arrival time on the island.
F<sc>ig</sc>. 2
Fig. 2
Specular schematic trees encompassing the three Sardinian-specific haplogroups (N1b1a9, U5b1i1, K1a2d) whose age estimates might predate the Neolithic (>7.8 Kya) and the Sardinian haplogroups H1 and H3. Age estimates were calculated by employing two mutation rates, by Soares et al. (2009) (tree on the left) and by Posth et al. (2016) (tree on the right). Triangles and continuous lines indicate ML estimates. Circles and dashed lines indicate BEAST estimates. Ages are according to the (non-linear) time scale on the bottom. Colored shadings show the largest confidential intervals of age estimates. For details concerning the age estimates of all SSHs see supplementary figure S2, Supplementary Material online.
F<sc>ig</sc>. 3
Fig. 3
Schematic representation of K1a2 (panel A), U5b1i (panel B), and N1b1a (panel C) phylogenies. Subclades are represented by triangles, while singletons by lines. The width of triangles is proportional to the number of both modern and ancient mitogenomes, while the height to the age of the clades (Kya) estimated with ML and the molecular clock proposed by Soares et al. (2009). These and the ages obtained with other methods/rates are listed in supplementary table S3, Supplementary Material online. Colours indicate the geographical origin of samples according to the legend. Ancient samples (whose codes are those reported in supplementary table S7 and supplementary fig. S5, Supplementary Material online) are placed in correspondence of their radiocarbon calibrated ages. The name of Sardinian-specific haplogroups is underlined and in a purple field .
F<sc>ig</sc>. 4
Fig. 4
Spatial frequency distribution map of haplogroup H3. Dots indicate the geographic locations of the surveyed populations. Population frequencies (%) are provided in supplementary table S9, Supplementary Material online. We constructed spatial frequency distribution plots with the program Surfer 9 (Golden Software, http://www.goldensoftware.com/products/surfer). The inset shows the Bayesian skyline plot (BSP) showing effective population size trends of Sardinian H3 mtDNAs. The black and white lines are the median estimates obtained by employing the mutation rates proposed by Soares et al. (2009) and Posth et al. (2016), respectively; the grey shading shows the highest posterior density limits.
See this image and copyright information in PMC

References

    1. Achilli A, Rengo C, Magri C, Battaglia V, Olivieri A, Scozzari R, Cruciani F, Zeviani M, Briem E, Carelli V, et al. 2004. The molecular dissection of mtDNA haplogroup H confirms that the Franco-Cantabrian glacial refuge was a major source for the European gene pool. Am J Hum Genet. 75:910–918. - PMC - PubMed
    1. Behar DM, Harmant C, Manry J, van Oven M, Haak W, Martinez-Cruz B, Salaberria J, Oyharçabal B, Bauduer F, Comas D, et al. 2012. The Basque paradigm: genetic evidence of a maternal continuity in the Franco-Cantabrian region since pre-Neolithic times. Am J Hum Genet. 90:486–493. - PMC - PubMed
    1. Berger J-F, Guilaine J.. 2009. The 8200 cal BP abrupt environmental change and the Neolithic transition: a Mediterranean perspective. Quat Int. 200:31–49.
    1. Broodbank C. 2013. The making of the middle sea: a history of the Mediterranean from the beginning to the emergence of the classical world. London: Thames & Hudson.
    1. Costa MD, Pereira JB, Pala M, Fernandes V, Olivieri A, Achilli A, Perego UA, Rychkov S, Naumova O, Hatina J, et al. 2013. A substantial prehistoric European ancestry amongst Ashkenazi maternal lineages. Nat Commun. 4:2543.. - PMC - PubMed