Human-mediated introgression of exotic chukar (Alectoris chukar, Galliformes) genes from East Asia into native Mediterranean partridges

Mediterranean red-legged (Alectoris rufa) and rock (Alectoris graeca) partridge populations are affected by genetic pollution. The chukar partridge (Alectoris chukar), a species only partly native to Europe, is the most frequently introgressive taxon detected in the genome of hybrid partridges. Both theoretical (evolutionary) and practical (resources management) matters spur to get insight into the geographic origin of the A. chukar hybridizing swarm. The phenotypic A. rufa populations colonizing the easternmost part of the distribution range of this species, the islands of Elba (Italy) and Corsica (France), were investigated. The analysis of both mitochondrial (mtDNA: Cytochrome-b gene plus Control Region: 2,250 characters) and nuclear (Short Tandem Repeats, STR; Random Amplified Polymorphic DNA, RAPD) genomes of 25 wild (Elba) and 20 captive (Corsica) partridges, disclosed spread introgression of chukar origin also in these populations. All mtDNA haplotypes of Elba and Corsica partridges along with those we obtained from other A. rufa (total, n = 111: Italy, Spain, France) and A. graeca (n = 6, Italy), were compared with the mtDNA haplotypes of chukars (n = 205) sampled in 20 countries. It was found that the A. chukar genes detected in red-legged (n = 43) and rock partridges (n = 4) of Spain, France and Italy as well as in either introduced (Italy) or native (Greece, Turkey) chukars (n = 35) were all from East Asia. Hence, a well-defined geographic origin of the exotic chukar genes polluting the genome of native Mediterranean A. rufa and A. graeca (inter-specific level) as well as A. chukar (intra-specific level), was demonstrated.     

Glycyl tRNA synthetase mutations in Charcot-Marie-Tooth disease type 2D and distal spinal muscular atrophy type V

Charcot-Marie-Tooth disease type 2D (CMT2D) and distal spinal muscular atrophy type V (dSMA-V) are axonal peripheral neuropathies inherited in an autosomal dominant fashion. Our previous genetic and physical mapping efforts localized the responsible gene(s) to a well-defined region on human chromosome 7p. Here, we report the identification of four disease-associated missense mutations in the glycyl tRNA synthetase gene in families with CMT2D and dSMA-V. This is the first example of an aminoacyl tRNA synthetase being implicated in a human genetic disease, which makes genes that encode these enzymes relevant candidates for other inherited neuropathies and motor neuron diseases.     

Evidence for association of endothelial cell nitric oxide synthase gene polymorphism with earlier progression to end-stage renal disease in a cohort of Hellens from Greece and Cyprus

Nitric oxide (NO) is thought to be an important factor in the deterioration of renal function. A variable-number tandem 27-bp repeat in intron 4 of the endothelial cell nitric oxide synthase (NOS3) gene has been found to be associated with the plasma levels of NO metabolites. Two alleles are of varied frequencies in different populations (a and b). The shorter allele a has been associated in Japanese populations with the progression of renal disease. Here we investigated this hypothesis by studying the putative role of this polymorphism in a Hellenic population of patients with end-stage renal disease (ESRD). We analyzed the genotypes of 361 ESRD patients and 295 healthy Hellens from Greece and Cyprus. The frequencies of NOS3-4bb, NOS3-4ab, and NOS3-4aa were 0.69, 0.27, and 0.03, respectively, in the control group and 0.71, 0.24, and 0.04 in the group of patients. The data in the two populations were analyzed by the chi-square and Fisher's exact tests. The frequencies of these three genotypes of NOS3-4 polymorphism in the Hellenic population of Greece and Cyprus are similar to those observed in other Caucasian populations. Moreover, our results from three patient groups, autosomal dominant polycystic kidney disease (ADPKD), diabetes mellitus (DM), and non-DM, showed that the frequencies of aa and ab genotypes in the patient populations were not significantly different from those observed in the control group. This work indicates that NOS3-4 polymorphism does not show any association with the development of ESRD in this studied European population. However, examination of the data regarding progression to ESRD within 5 years or after more than 5 years following clinical diagnosis of ADPKD provided evidence of statistical difference (p = 0.048, before Bonferroni correction), with faster progression in the group of ADPKD patients who carried allele a.     

Epigenetic chromatin modifiers in barley: I. Cloning, mapping and expression analysis of the plant specific HD2 family of histone deacetylases from barley, during seed development and after hormonal treatment

Epigenetic phenomena have been associated with modifications of chromatin structure. These are achieved, in part, by histone post-translational modifications including acetylations and deacetylations, the later being catalyzed by histone deacetylaces (HDACs). Eukaryotic HDACs are grouped into three major families, RPD3/HDA1, SIR2 and the plant-specific HD2. HDAC genes have been analyzed from model plants such as Arabidopsis , rice and maize and have been shown to be involved in various cellular processes including seed development, vegetative and reproductive growth and responses to abiotic and biotic stress, but reports on HDACs from other crops are limited. In this work two full-length cDNAs ( HvHDAC2-1 and HvHDAC2-2 ) encoding two members of the plant-specific HD2 family, respectively, were isolated and characterized from barley ( Hordeum vulgare ), an agronomically important cereal crop. HvHDAC2-1 and HvHDAC2-2 were mapped on barley chromosomes 1H and 3H, respectively, which could prove useful in developing markers for marker-assisted selection in breeding programs. Expression analysis of the barley HD2 genes demonstrated that they are expressed in all tissues and seed developmental stages examined. Significant differences were observed among tissues and seed stages, and between cultivars with varying seed size, suggesting an association of these genes with seed development. Furthermore, the HD2 genes from barley were found to respond to treatments with plant stress-related hormones such as jasmonic acid (JA), abscisic acid (ABA) and salicylic acid (SA) implying an association of these genes with plant resistance to biotic and abiotic stress. The expression pattern of HD2 genes suggests a possible role for these genes in the epigenetic regulation of seed development and stress response.     

Molecular evolution of the Asian francolins (Francolinus, Galliformes): A modern reappraisal of a classic study in speciation

We investigated the evolution of the Asian francolins, five little known species in the genus Francolinus (Phasianidae). Evolutionary affinities of two of these species, F. gularis (swamp francolin) and F. pondicerianus (grey francolin), has long remained unclear. In contrast, the other three species, F. pintadeanus (Chinese francolin), F. pictus (painted francolin) and F. francolinus (black francolin) have been cast among the "spotted francolins" on a morphological and ecological basis. Previous molecular DNA investigations including Asian francolins mostly relied upon partial gene sequencing of one specimen per species (no more than three species and with the exclusion of F. pictus). Therefore, fundamental questions do persist. What relationship exists among the spotted and the other Asian francolins? What is the geographic origin of the black francolin, the species with the largest distribution range? How did the geological history influence the diversification of francolins across Asia? We sequenced the entire Control Region of the mitochondrial DNA in 228 samples of all five Asian francolin species, which were collected in 16 countries (from East Europe to East Asia). We constructed a molecular phylogeny according to four different procedures. We showed the monophyly of each of the Asian francolins and the spotted group, while that of the entire Asian group was presumed according to a biogeographical model we proposed. The splitting of the genus Francolinus occurred ～17.4Ma (95% HPD: 13.4-22.1) while the spotted francolins diverged ～10.5Ma (7.0-14.9). We resolved the most recent common ancestor to painted and black francolin as being in the Indian sub-continent, thus suggesting a westwards adaptive radiation of the latter. In Pakistan, we identified F. f. asiae representatives in the Northern Areas and in the Sindh. The latter represents a relict population of Indian fauna within the Pakistani range of the Great Rann of Kachchh.     

Genetic insight into Mediterranean chukar (Alectoris chukar, Galliformes) populations inferred from mitochondrial DNA and RAPD markers

The chukar (Alectoris chukar, Galliformes) is one of the most important game birds as it is widely distributed and hunted over the whole of its range. The aim of this work was to assess the genetic differentiation as well as the possible presence of hybrid specimens in A. chukar populations from Italy, Greece and Cyprus. To provide phylogenetic context, conspecific, allopatric specimens from Israel, Georgia, Armenia, Kazakhstan, Afghanistan, Pakistan, Mongolia, China and USA were compared. Sequencing of the mitochondrial DNA (mtDNA) Control Region supplied information on the ancestry of A. chukar populations, whereas Random Amplified Polymorphic DNA (RAPD) fingerprinting was used to assess whether hybridization had occurred. The Italian population was found to be an inter-specific mixture of A. chukar and A. rufa (i.e., the red-legged partridge) mtDNA lineages, whereas the representatives from Greece and Cyprus showed only the A. chukar maternal line. RAPD markers revealed introgression with A. rufa genes in the Italian population, whereas no A. chukar × A. rufa hybrid specimens were detected in the eastern Mediterranean populations. The genetic data obtained from the Italian A. chukar population as well as from a few Greek specimens pointed against their Mediterranean kinship, suggesting relationships with A. chukar subspecies from the easternmost part of the Asian continent.     

Aberrant Apoptotic Response of Colorectal Cancer Cells to Novel Nucleoside Analogues

Despite the increased understanding of colorectal cancer and the introduction of targeted drug therapy, the metastatic phase of the disease remains refractory to treatment. Since the deregulation of normal apoptosis contributes to the pathogenesis of colorectal cancer, novel nucleoside analogues were synthesized here and evaluated for their ability to induce apoptosis and cause cell death in two colorectal adeno-carcinoma cell lines, Caco-2 and HT-29. Three novel nucleoside analogues assessed here showed cytotoxic activity, as measured by the MTT assay against both cell lines: the IC₅₀ values ranged between 3 and 37 μM, with Caco-2 cells being more sensitive than HT-29 cells. Compared to camptothecin, the positive control, the nucleoside analogues were significantly less toxic to normal unstimulated leukocytes (p>0.05). Moreover, the nucleosides were able to induce apoptosis as measured by an increase in caspase 8 and caspase 3 activity above that of the control. This was additionally supported by data derived from Annexin V-FITC assays. Despite marginal changes to the mitochondrial membrane potential, all three nucleosides caused a significant increase in cytosolic cytochrome c (p>0.05), with a corresponding decrease in mitochondrial cytochrome c. Morphological analysis of both cell lines showed the rapid appearance of vacuoles following exposure to two of the nucleosides, while a third caused cellular detachment, delayed cytoplasmic vacuolisation and nuclear abnormalities. Preliminary investigations, using the autophagic indicator monodansylcadaverine and chloroquine as positive control, showed that two of the nucleosides induced the formation of autophagic vacuoles. In summary, the novel nucleoside analogues showed selective cytotoxicity towards both cancer cell lines and are effective initiators of an unusual apoptotic response, demonstrating their potential to serve as structural scaffolds for more potent analogues.     

Study of large inbred Friedreich ataxia families reveals a recombination between D9S15 and the disease locus

Friedreich ataxia is a neurodegenerative disorder with autosomal recessive inheritance. Precise linkage mapping of the Friedreich ataxia locus (FRDA) in 9q13-q21 should lead to the isolation of the defective gene by positional cloning. The two closest DNA markers, D9S5 and D9S15, show very tight linkage to FRDA, making difficult the ordering of the three loci. We present a linkage study of three large Friedreich ataxia families of Tunisian origin, with several multiallelic markers around D9S5 and D9S15. Haplotype data were used to investigate genetic homogeneity of the disease in these geographically related families. A meiotic recombination was found in a nonaffected individual, which excludes a 150-kb segment, including D9S15, as a possible location for the Friedreich ataxia gene and which should orient the search in the D9S5 region.