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Brunetto Chiarelli

Publications and source records attributed to Brunetto Chiarelli.

4 recordsLinked to original sources

The Etruscans: a population-genetic study.

The origins of the Etruscans, a non-Indo-European population of preclassical Italy, are unclear. There is broad agreement that their culture developed locally, but the Etruscans' evolutionary and migrational relationships are largely unknown. In this study, we determined mitochondrial DNA sequences in multiple clones derived from bone samples of 80 Etruscans who lived between the 7th and the 3rd centuries b.c. In the first phase of the study, we eliminated all specimens for which any of nine tests for validation of ancient DNA data raised the suspicion that either degradation or contamination by modern DNA might have occurred. On the basis of data from the remaining 30 individuals, the Etruscans appeared as genetically variable as modern populations. No significant heterogeneity emerged among archaeological sites or time periods, suggesting that different Etruscan communities shared not only a culture but also a mitochondrial gene pool. Genetic distances and sequence comparisons show closer evolutionary relationships with the eastern Mediterranean shores for the Etruscans than for modern Italian populations. All mitochondrial lineages observed among the Etruscans appear typically European or West Asian, but only a few haplotypes were found to have an exact match in a modern mitochondrial database, raising new questions about the Etruscans' fate after their assimilation into the Roman state.

Bone and Bones↗

Evidence for a genetic discontinuity between Neandertals and 24,000-year-old anatomically modern Europeans.

During the late Pleistocene, early anatomically modern humans coexisted in Europe with the anatomically archaic Neandertals for some thousand years. Under the recent variants of the multiregional model of human evolution, modern and archaic forms were different but related populations within a single evolving species, and both have contributed to the gene pool of current humans. Conversely, the Out-of-Africa model considers the transition between Neandertals and anatomically modern humans as the result of a demographic replacement, and hence it predicts a genetic discontinuity between them. Following the most stringent current standards for validation of ancient DNA sequences, we typed the mtDNA hypervariable region I of two anatomically modern Homo sapiens sapiens individuals of the Cro-Magnon type dated at about 23 and 25 thousand years ago. Here we show that the mtDNAs of these individuals fall well within the range of variation of today's humans, but differ sharply from the available sequences of the chronologically closer Neandertals. This discontinuity is difficult to reconcile with the hypothesis that both Neandertals and early anatomically modern humans contributed to the current European gene pool.

Animals↗

Ancient DNA analysis of the delta F508 mutation.

When working with highly degraded DNA, validating the results of a slightly polymorphic system always complicates the analysis because of the difficulties in recognizing contamination and artifacts. Recognition can be greatly simplified by employing a multiplex reaction that coamplifies the fragments together with several highly polymorphic markers, for instance, short tandem repeats. In this work, we successfully included newly designed oligonucleotide primers for the detection of delta F508, the most frequent mutation causing cystic fibrosis, in the commercial AmpFlSTR Profiler Plus PCR Amplification Kit (PE Applied Biosystems). This coamplification enabled us to test the hypothesis of a heterozygote advantage associated with cystic fibrosis-specifically, higher resistance to toxin-mediated diarrheas--in a Sicilian skeletal sample of individuals who died in a cholera epidemic in 1837. The proposed method should also be suitable for the genetic characterization of other slightly polymorphic loci tested on human and animal ancient DNA; it should permit simple authentication of results by comparing the fingerprints obtained from independent amplifications repeated several times.

Cystic Fibrosis↗

Chromosome mapping of Miller-Diecker, Smith-Magenis and RARA loci in non-human primates: implications in the evolution of human chromosome 17.

Molecular cytogenetics allows to verify chromosomal homologies previously hypothesised on the base of banding pattern comparison in different species. So far only the chromosome painting technique has been extensively used in studies of chromosomal evolution. This technique allows to detect only interchromosomal rearrangements. Human and Great Apes chromosomes basically differ by intrachromosomal rearrangements, in particular inversions; with chromosome painting it has just been possible to confirm the origin by fusion of human chromosome 2 and a reciprocal translocation in Gorilla, involving the homologous of chromosome 5 and 17. In order to verify intrachromosomal rearrangements in human chromosomal evolution, chromosome mapping of human loci in non-human primates is a useful approach. We mapped Miller-Diecker, Smith-Magenis and RARA loci localised on human chromosome 17, in Gorilla gorilla, Pongo pygmaeus, Macaca fascicularis and Cercopithecus aethiops. On the base of the obtained results it was possible to verify chromosomal rearrangements previously identified by banding, to achieve new informations about the controversial evolution of human chromosome 17, and to detect the occurrence of a paracentric inversion in the homologous in Cercopithecus aethiops.

Abnormalities, Multiple↗