Evaluation of genetic diversity in Sulla coronaria from different geographical populations in Tunisia by inter simple sequence repeat (ISSR)

Five oligonucleotides generating 116 markers complementary to simple sequence repeats were used in order to characterize wild and cultivated ecotypes of Sulla coronaria and assess genetic diversity suitable in breeding programs. While analysing populations, a large genetic variability was revealed and supported by the preferentially allogamous mating system of the species. Moreover, the highest level of intra-population variations (Hpop/Hsp = 69.9) either of wild or cultivated accessions have been strongly evidenced by a significant adaptation to variety of habitats. In addition, the structure of populations was independent from the bioclimatic stages and was not affected by environmental factors as shown by the non correlation between the geographic and the Nei and Li’s genetic distances (r= 0.461 and p=0.068>0.05). The unweighted pair group method with arithmetic mean (UPGMA) genetic relationships showed that some local spontaneous accessions characterised by an orthotropic port (Jebel Zit and Beja) were also molecularly similar to other cultivars.Key words: Sulla coronaria, wild and cultivated forms, intra and inter-populations variability, microsatellites (ISSRs), bioclimatic stages

Assessment of the genetic variation in alfalfa genotypes using SRAP markers for breeding purposes

The molecular diversity studies of alfalfa (Medicago sativa L.) germplasm could contribute to a more precise selection of parental populations in many breeding programs. Sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity of 110 individual plants from 13 selected alfalfa cultivars, landraces, and natural populations from Tunisia, Australia, Serbia, and Kazakhstan. Ten polymorphic SRAP primer combinations generated 137 alleles with 0.90 polymorphism information content. The percentage of polymorphic bands per genotype ranged from 57.66% to 70.07% with a mean of 64.29% and overall value of 100%. The genotype Sardi 10 had the highest value for the effective number of alleles; Nei's gene diversity and Shannon information index, exhibited the highest variability level (Ne = 1.453, He = 0.259, I = 0.381, respectively), whereas the genotype Nera exhibited the lowest variability level (Ne = 1.359, He = 0.211, I = 0.317, respectively). The AMOVA analysis showed that 68% of the variance was within the genotypes; this was in line with the coefficient of genetic differentiation (Gst = 0.370). The genetic relatedness of alfalfa individuals analyzed by the neighbor-joining dendrogram was consistent with the Bayesian model-based clustering approach. The exceptions were individuals from genotypes Slavija and Nera, which were grouped separately by STRUCTURE analyses. These results provide useful information for the management of alfalfa genetic resources and the rational use of local and foreign alfalfa populations in breeding programs focused on the development of new, high-yielding cultivars more adapted to drought conditions in North Africa

Morphology and Genetic Studies of Cymodocea Seagrass Genus in Tunisian Coasts

International audienceSpecimens of Cymodocea (Viridiplantae, Magnoliophyta) collected on the Tunisian coasts showed a particular morphological and anatomical difference with the classical descriptions of Cymodocea nodosa (Ucria) Asch. the only species of this genus reported in the Mediterranean Sea. In order to precise the taxonomic identity of the new specimens we aimed in this work (i) to verify the identity of the new forms, (ii) to evaluate the genetic diversity of the population, (iii) to test the validity of the existing identification keys of the Tunisian Cymodocea populations. Four stations located in two regions of the Tunisian coasts were sampled. Leaf morphological and anatomical characters used in taxonomic identification were measured (e.g number of cross veins, shape of the apex). The genetic study was performed using three most common chloroplast markers for plant characterization (DNA barcodes rbcL, matK and trnHpsbA). The morphological study revealed the presence of three C. nodosa morphotypes, described here for the first time, while the molecular characterization did not allow the discrimination of these morphological types. In regard to these results, it would be wise to review the classical identification keys of the Cymodocea genus

Spectrum of Genetic Diseases in Tunisia: Current Situation and Main Milestones Achieved

Genetic diseases in Tunisia are a real public health problem given their chronicity and the lack of knowledge concerning their prevalence and etiology, and the high rates of consanguinity. Hence, we performed systematic reviews of the literature in order to provide a more recent spectrum of these disorders and to expose the challenges that still exist to tackle these kinds of diseases. A manual textual data mining was conducted using MeSH and PubMed databases. Collected data were classified according to the CIM-10 classification and the transmission mode. The spectrum of these diseases is estimated to be 589 entities. This suggests remarkable progress through the development of biomedical health research activities and building capacities. Sixty percent of the reported disorders are autosomal recessive, which could be explained by the high prevalence of endogamous mating. Congenital malformations (29.54%) are the major disease group, followed by metabolic diseases (22%). Sixty percent of the genetic diseases have a known molecular etiology. We also reported additional cases of comorbidity that seem to be a common phenomenon in our population. We also noticed that epidemiological data are scarce. Newborn and carrier screening was only limited to pilot projects for a few genetic diseases. Collected data are being integrated into a database under construction that will be a valuable decision-making tool. This study provides the current situation of genetic diseases in Tunisia and highlights their particularities. Early detection of the disease is important to initiate critical intervention and to reduce morbidity and mortality

Alpha-mannosidosis in Tunisian consanguineous families: Potential involvement of variants in GHR and SLC19A3 genes in the variable expressivity of cognitive impairment

International audienceAlpha-Mannosidosis (AM) is an ultra-rare storage disorder caused by a deficiency of lysosomal alpha-mannosidase encoded by the MAN2B1 gene. Clinical presentation of AM includes mental retardation, recurrent infections, hearing loss, dysmorphic features, and motor dysfunctions. AM has never been reported in Tunisia. We report here the clinical and genetic study of six patients from two Tunisian families with AM. The AM diagnosis was confirmed by an enzymatic activity assay. Genetic investigation was conducted by Sanger sequencing of the mutational hotspots for the first family and by ES analysis for the second one. In the first family, a frameshift duplication p.(Ser802GlnfsTer129) was identified in the MAN2B1 gene. For the second family, ES analysis led to the identification of a missense mutation p.(Arg229Trp) in the MAN2B1 gene in four affected family members. The p.(Ser802GlnfsTer129) mutation induces a premature termination codon which may trigger RNA degradation by the NMD system. The decrease in the levels of MAN2B1 synthesis could explain the severe phenotype observed in the index case. According to the literature, the p.(Arg229Trp) missense variant does not have an impact on MAN2B1 maturation and transportation, which correlates with a moderate clinical sub-type. To explain the intra-familial variability of cognitive impairment, exome analysis allowed the identification of two likely pathogenic variants in GHR and SLC19A3 genes potentially associated to cognitive decline. The present study raises awareness about underdiagnosis of AM in the region that deprives patients from accessing adequate care. Indeed, early diagnosis is critical in order to prevent disease progression and to propose enzyme replacement therapy

The Mediterranean region under climate change

This book has been published by Allenvi (French National Alliance for Environmental Research) to coincide with the 22nd Conference of Parties to the United Nations Framework Convention on Climate Change (COP22) in Marrakesh. It is the outcome of work by academic researchers on both sides of the Mediterranean and provides a remarkable scientific review of the mechanisms of climate change and its impacts on the environment, the economy, health and Mediterranean societies. It will also be valuable in developing responses that draw on “scientific evidence” to address the issues of adaptation, resource conservation, solutions and risk prevention. Reflecting the full complexity of the Mediterranean environment, the book is a major scientific contribution to the climate issue, where various scientific considerations converge to break down the boundaries between disciplines