Uniparental markers reveal new insights on subcontinental ancestry and sex-biased admixture in Brazil.

The Brazilian population is a product of asymmetric admixture among European men and Amerindian and African women. However, Brazilian subcontinental ancestry is scarcely documented, especially regarding its African roots. Here, we aimed to unveil the uniparental continental and subcontinental contributions from distinct Brazilian regions, including South (n = 43), Southeast (n = 71), the poorly genetically characterized Central-Western region (n = 323), and a subset of unique Brazilian Amerindians (n = 24), in the context of their genome-wide ancestral contributions. The overwhelming majority of European Y haplogroups (85%) contrast sharply with the predominant African and Amerindian mtDNA haplogroups (73.2%) in admixed populations, whereas in Amerindians, non-Native haplogroups could only be detected through the paternal line. Our in-depth investigation of uniparental markers showed signals of an Andean and Central-Brazilian Amerindian maternal contribution to Southeastern and Central-Western Brazil (83.1 ± 2.1% and 56.9 ± 0.2%, respectively), the last having the highest paternal Amerindian ancestry yet described for an admixed Brazilian region (9.7%) and contrasting with higher Southern-Brazilian Amerindian contribution to Southern Brazil (59.6 ± 1%). Unlike the higher African Bantu contribution previously reported for the South and Southeast, a relevant Western African non-Bantu contribution was detected in those regions (85.7 ± 5% and 71.8 ± 10.8% respectively). In contrast, a higher Bantu contribution was described for the first time in the Central-West (64.8 ± 1.3% maternal and 86.9 ± 9.6% paternal). We observed sex-biased signatures consistent with the historically recorded Brazilian colonization and added new insights in the subcontinental maternal ancestry of Brazilians from regions never studied at this level.

Mitochondrial variability in the Mediterranean area: a complex stage for human migrations.

CONTEXT: The Mediterranean area has always played a significant role in human dispersal due to the large number of migratory events contributing to shape the cultural features and the genetic pool of its populations. OBJECTIVE: This paper aims to review and diachronically describe the mitogenome variability in the Mediterranean population and the main demic diffusions that occurred in this area over time. METHODS: Frequency distributions of the leading mitochondrial haplogroups have been geographically and chronologically evaluated. The variability of U5b and K lineages has been focussed to broaden the knowledge of their genetic histories. RESULTS: The mitochondrial genetic makeup of Palaeolithic hunter-gatherers is poorly defined within the extant Mediterranean populations, since only a few traces of their genetic contribution are still detectable. The Neolithic lineages are more represented, suggesting that the Neolithic revolution had a marked effect on the peopling of the Mediterranean area. The largest effect, however, was provided by historical migrations. CONCLUSION: Although the mitogenome variability has been widely used to try and clarify the evolution of the Mediterranean genetic makeup throughout almost 50 000 years, it is necessary to collect whole genome data on both extinct and extant populations from this area to fully reconstruct and interpret the impact of multiple migratory waves and their cultural and genetic consequences on the structure of the Mediterranean populations.

Differential ecological traits of two Phlebotomus sergenti mitochondrial lineages in southwestern Europe and their epidemiological implications.

OBJECTIVES: The introduction of leishmaniasis in a new area requires a well-established population of the sandfly vector species of the parasite. No autochthonous cases of anthroponotic cutaneous leishmaniasis have been detected in southwestern Europe, and Leishmania infantum is the only causative agent of leishmaniasis in this area. Phlebotomus sergenti, the main vector of Leishmania tropica, is commonly found in the Iberian Peninsula at sufficient densities to be able to act as a vector. It is characterised by high genetic diversity and classified in four mitochondrial lineages. Our aim was to analyse the composition and distribution of P. sergenti mitochondrial lineages in southwestern Europe given the possibility of phenotypic differences of biomedical importance between them. METHODS: Sandflies were captured in the Iberian Peninsula and on the Canary and Balearic Islands. Mitochondrial lineage identification of 137 P. sergenti was performed using a novel PCR-RFLP that avoids the necessity of gene sequencing. RESULTS: Two lineages were evidenced, the typical Iberian one (lineage I) and another, held in common with North Africa (lineage III), that show a distinctive distribution. P. sergenti lineage I shows a better correlation to the bioclimatic diversity in southwestern Europe. Conversely, P. sergenti lineage III prefers warmer temperatures and less precipitation, which are typical of the Mediterranean. CONCLUSION: Lineage I seems to have adaptive advantages given its wider tolerance to temperature and altitude than lineage III, and it would seem more suitable to lead a potential geographical expansion towards the rest of Europe.

Assessing diversity of King Crab Lithodes spp. in the south-eastern pacific using phylogeny and molecular species delimitation methods.

The purpose of this study was to test the hypothesis that the genetic diversity of commercially significant species of King Crabs (Lithodes spp.) along the south-eastern Pacific (SEP) comprises different independent evolutionary units (IEUs) with spatially isolated distribution. Nine localities from inner and open waters along the SEP Chilean coast (39°S-55°S) were sampled. We analyzed sequences from 173 individuals for the mitochondrial gene Cytochrome oxidase I (COX-I), 151 individuals for the Internal Transcribed Spacer 1 (ITS) and 135 for the structural ribosomal RNA (28S). Genetic delimitation was performed through three analytical methods: ABGD, GMYC, and its Bayesian implementation, bGMYC. Bayesian phylogenetic analyses and haplotype networks were also performed. Divergence time between clades was assessed for the COX-I marker and estimated from known evolutionary rates for this marker in other crustacean species and fossil calibration from other Anomuran species. Delimitation analyses, phylogenetic analyses, and mitochondrial haplotype networks suggested the presence of two deeply divergent mitochondrial lineages of Lithodes in the SEP, referred to as Clade1 and Clade 2. Nuclear markers showed low phylogenetic resolution and therefore were unsuitable for molecular species delimitation. Divergence time analysis of the mitochondrial lineages suggests a separation between Clades of approximately 2.3 Mya. The divergence time obtained suggested that Pliocene glaciations and deglaciations cycles could be involved in hybridization events between Lithodes IEUs at southern tip of South American coasts. The different frequencies of Lithodes haplotypes in inner and open water environments along SEP coasts could be explained by events such as the last glacial maximum or by differences in the adaptation of each clade to different environments. These findings support the necessity of evaluating the taxonomic status of Lithodes individuals found along SEP coasts under an integrative taxonomy approach or through markers with other evolution rates than those already used.

An enigmatic population of Alsodes (Anura, Alsodidae) from the Andes of central Chile with three species-level mitochondrial lineages.

The genus Alsodes is the most diverse amphibian taxon of southern Andes, where a series of endemic species occur from north to south (∼33° to 48°30'S), mainly on the western slopes (Chile), with little overlap of geographic ranges. In this study, we describe a new population of Alsodes from the western slopes of the Andes (Fundo El Rosario, 36°52'S), located in a section of this mountain range where it is not clear which congeneric species inhabit. Phylogenetic analyses show that this population presents a mix of mitochondrial DNA related to three nominal species, A. hugoi, A. igneus and A. pehuenche, although the last is mainly present. However, the population presents external characteristics attributable to A. hugoi and A. igneus, differing notably from A. pehuenche. The population inhabits a stream surrounded by temperate deciduous forests at 1130 m elevation, an environment similar to that of A. hugoi and A. igneus, but very different from that of A. pehuenche (high Andean steppe environments between 2000 and 2500 m). This finding represents an enigma from the evolutionary and biogeographical point of view, because it might involve hybridization and/or introgression phenomena between more than two species. As the taxonomic status of this population cannot be determined with the available genetic and morphological evidence, we speculate about its probable origin, taking into account the scarce knowledge of the geographic distributions of the species of Alsodes in the area.