Search results for "Founder effect"
showing 10 items of 31 documents
Clonal population structure of the chestnut blight fungus in expanding ranges in southeastern Europe.
2008
Expanding populations are often less genetically diverse at their margins than at the centre of a species' range. Established, older populations of the chestnut blight fungus, Cryphonectria parasitica, are more variable for vegetative compatibility (vc) types than in expanding populations in southeastern Europe where C. parasitica has colonized relatively recently. To test whether vc types represent clones, we genotyped 373 isolates of C. parasitica from southern Italy, Romania, Bulgaria, Macedonia, Greece and Turkey using 11 sequence-characterized amplified region (SCAR) markers. Ten SCAR loci and six vegetative incompatibility (vic) loci were polymorphic in these samples. These population…
Founder mutations in BRCA1 and BRCA2 genes
2007
BRCA1 and BRCA2 germline mutations contribute to a significant number of familial and hereditary breast and/or ovarian cancers. The proportion of high-risk families with breast and/or ovarian cancer cases due to mutations in these tumor suppressor genes varies widely among populations. In some population, a wide spectrum of different mutations in both genes are present, whereas in other groups specific mutations in BRCA1 and BRCA2 have been reported with high frequency. Most of these mutations are prevalent in restricted populations as consequence of a founder effect. The comparison of haplotypes between families with the same mutation can distinguish whether high-frequency alleles derive f…
Modern taurine cattle descended from small number of near-eastern founders.
2012
Archaeozoological and genetic data indicate that taurine cattle were first domesticated from local wild ox (aurochs) in the Near East some 10,500 years ago. However, while modern mitochondrial DNA (mtDNA) variation indicates early Holocene founding event(s), a lack of ancient DNA data from the region of origin, variation in mutation rate estimates, and limited application of appropriate inference methodologies have resulted in uncertainty on the number of animals first domesticated. A large number would be expected if cattle domestication was a technologically straightforward and unexacting region-wide phenomenon, while a smaller number would be consistent with a more complex and challengin…
Analysis ofBRCA1andBRCA2genes in Spanish breast/ovarian cancer patients: A high proportion of mutations unique to Spain and evidence of founder effec…
2003
We screened index cases from 410 Spanish breast/ovarian cancer families and 214 patients (19 of them males) with breast cancer for germ-line mutations in the BRCA1 and BRCA2 genes, using SSCP, PTT, CSGE, DGGE, and direct sequencing. We identified 60 mutations in BRCA1 and 53 in BRCA2. Of the 53 distinct mutations observed, 11 are novel and 12 have been reported only in Spanish families (41.5%). The prevalence of mutations in this set of families was 26.3%, but the percentage was higher in the families with breast and ovarian cancer (52.1%). The lowest proportion of mutations was found in the site-specific female breast cancer families (15.4%). Of the families with male breast cancer cases, …
Molecular variation in the Odh gene in Chilean natural populations of Drosophila subobscura
2008
A 793-nucleotide fragment from the D. subobscura Odh gene was sequenced in 46 lethal chromosomal lines from two South American colonizing populations (18 from Santiago de Chile and 28 from Puerto Montt). Only eight different haplotypes were found and, with just one exception, all had previously been detected in North American samples. The exception probably corresponds to a genetic exchange between two American haplotypes. Our results confirm the loss in genetic variability due to the recent founder event, and the high resemblance between the two colonized hemispheres. One haplotype is entirely associated with the O5 inversion, the same association found in North America. Two different hapl…
The genetics of human migration: Tracing migrations through the genome
2015
Various academic disciplines shed light on human migrations, helping us to reconstruct the past. Studying the genetic diversity of human populations today reveals past demographic and migratory events that have left an imprint on our genome. Armed with knowledge of migrations in prehistoric times, we can test hypotheses put forward in other scientific disciplines. Similarly, the distribution of genetic diversity in the future will largely depend on today’s extensive human migrations, facilitated by technological advances.
Downy-oak woods of Italy: phytogeographical remarks on a controversial taxonomic and ecologic issue
2014
The importance of downy oak as an integral component of the "submediterranean" woods has been underscored by many studies. Nevertheless, terms like "submediterranean" and "downy oak" are some of the most poorly understood concepts in European phytogeographic and taxonomic research. Downy oak is well known to be a problematic taxon. The name "Quercus pubescens" (= Q. humilis) combines populations characterized by increasing phenotypic and genomic polymorphisms along north-south gradients, which is explained as the result of a "founder effect" produced by a relatively fast post-glacial re-colonization of the northern areas through rare long-distance dispersal events. On the other hand, polymo…
Mutations in KIAA0586 Cause Lethal Ciliopathies Ranging from a Hydrolethalus Phenotype to Short-Rib Polydactyly Syndrome
2015
KIAA0586, the human ortholog of chicken TALPID3, is a centrosomal protein that is essential for primary ciliogenesis. Its disruption in animal models causes defects attributed to abnormal hedgehog signaling; these defects include polydactyly and abnormal dorsoventral patterning of the neural tube. Here, we report homozygous mutations of KIAA0586 in four families affected by lethal ciliopathies ranging from a hydrolethalus phenotype to short-rib polydactyly. We show defective ciliogenesis, as well as abnormal response to SHH-signaling activation in cells derived from affected individuals, consistent with a role of KIAA0586 in primary cilia biogenesis. Whereas centriolar maturation seemed una…
4843delC of the BRCA1 gene is a possible founder mutation in Southern Italy (Sicily).
2007
Various studies have been published in Italy regarding the different BRCA1 mutations, but only the BRCA1-5083del19 mutation is recurrent and specific to individuals of Italian descent with a founder effect on the Calabrian population. In our previous study, BRCA1-5083del19 mutation carriers were found in four index cases of 106 Sicilian patients selected for familial and/or hereditary breast/ovarian cancers. The high frequency rate of this mutation identified in the Sicilian population led us to perform haplotype analysis in all family carriers. Five highly polymorphic microsatellite markers were used (D17S1320, D17S932, D17S1323, D17S1326, D17S1325) to establish whether or not all these fa…
Is BRCA1-5083del19, identified in breast cancer patients of Sicilian origin, a Calabrian founder mutation?
2007
Various studies have been published in Italy regarding the different BRCA1 mutations, but only the BRCA1-5083del19 mutation is recurrent and specific to individuals of Italian descent with a founder effect on the Calabrian population. In our previous study, BRCA1-5083del19 mutation carriers were found in four index cases of 106 Sicilian patients selected for familial and/or hereditary breast/ovarian cancers. The high frequency rate of this mutation identified in the Sicilian population led us to perform haplotype analysis in all family carriers. Five highly polymorphic microsatellite markers were used (D17S1320, D17S932, D17S1323, D17S1326, D17S1325) to establish whether or not all these fa…