Breeding system and pollination biology of the semidomesticated fruit tree, Tamarindus indica L. (Leguminosae: Caesalpinioideae): Implications for fruit production, selective breeding, and conservation of genetic resources

In this paper, we provide data on the breeding system of Tamarindus indica, examining fruit production as well as pollen tube growth under different controlled pollination experiments (open, cross and selfpollination). We discuss implications of the results for management for fruit production in Tamarind, conservation of genetic resources and the potential for selective breeding. Observation of the germination and the pollen tubes growth under various pollination modes show that the tamarind is an incompatible species partially. This incompatibility appears at the pre level zygotic (IE on the level of the stigmatic, style and ovary) and post zygotic by the abortion of seeds

Genetic diversity of Tamarindus indica populations: Any clues on the origin from its current distribution?

Tamarindus indica is a domesticated species of high economic value for the Sahel region. Despite this importance, very few data is available on its diversity as well as its structure leading to controversialdiscussions on its origin. Thus it is questionable whether the knowledge of its genetic diversity and organisation may help in identifying the area of its origin. We have studied 10 populations using markers RAPDs with the seeds collected from Asia (India and Thailand), Africa (Burkina Faso, Senegal, Kenya and Tanzania), from three islands (Madagascar, Réunion and Guadeloupe). The results showed that T. indica has a high intra population genetic variability with a higher value obtained in the population from Cameroon. This high intra-population variability did not allow us to determinate the origin of the species. However, if we take into account the paleontological and anthropological results, we can assume that T. indica has an African origin

Comparaison des diversités génétiques de Dacryodes edulis (G.Don) H.J. Lam et de Dacryodes buettneri (Engel.) H.J. Lam (Burséracées), deux espèces forestières utiles en Afrique centrale

Dacryodes buettneri et Dacryodes edulis sont des espèces à usages multiples en Afrique centrale. Elles servent principalement de bois d’oeuvre et de fruitier. Des échantillons de leurs folioles ont été récoltés sur 694 arbres répartis dans 29 populations au Cameroun et au Gabon, afin d’extraire l’ADNn et amplifier cinq marqueurs microsatellites. Les paramètres génétiques des populations ont été calculés pour évaluer et comparer leur diversité génétique. Les moyennes des nombres d’allèles sont respectivement 4,43 ± 1,37 et 5,36 ± 1,13. Il n’existe pas de différence significative dans la répartition des nombres d’allèles par locus entre les espèces. Les paramètres de la diversité intra-population de D. buettneri (P = 0,76 ± 0,15; Hatt = 0,35 ± 0,06 et Hobs = 0,26 ± 0,04) sont significativement inférieurs à ceux de D. edulis (P = 0,9 ± 0,12; Hatt = 0,47 ± 0,05 et Hobs = 0,41 ± 0,07), alors que le coefficient de consanguinité de D. buettneri (F = 0,25 ± 0,08) est deux fois supérieur à celui de la deuxième espèce (F = 0,12 ± 0,03). Un important flux de gènes inter-espèce a été trouvé, Nm = 0,44. Les analyses ont ressorti trois groupes de populations, séparés par la distance géographique et l’isolement taxonomique. D. edulis se croise parfaitement si les individus sont géographiquement proches, même avec les individus spontanés forestiers. Aucune séparation variétale au sein de D. edulis n’a été détectée. Cette étude est une contribution à la valorisation de la diversité génétique des espèces forestières africaines pour une conservation durable.Mots clés : Espèces à usages multiples, marqueurs microsatellites, génétique de populations, conservation durable

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Measuring therapeutic efficacy in the changing paradigm of castrate-resistant prostate cancer.

Item does not contain fulltextOne of the current challenges in the evaluation of novel agents for the treatment of advanced prostate cancer is the identification of a surrogate end point for overall survival (OS). Prostate-specific antigen (PSA) levels have been used as a screening tool and a biomarker of response to both hormonal and cytotoxic agents. However, PSA levels do not seem to be a suitable surrogate end point for OS in trials of targeted agents for castrate-resistant prostate cancer (CRPC). These findings suggest the need for adopting measures of efficacy that more accurately reflect the mechanisms of action of these agents in phase II trials, in order to realize improvements in OS in the phase III setting. The Prostate Cancer Clinical Trials Working Group (PCWG2) have recently made recommendations for the design of future trials and advised that PSA levels should not be the sole criterion on which to base clinical decisions. Here, we appraise the end points that have been used in phase II and III trials in patients with CRPC, and highlight the need for the adoption of the PCWG2 guidelines, the recommendations of which include radiographic imaging, in addition to bone scintigraphy, and symptomatic or radiographic disease progression criteria

Genetic Diversity and Population Structure of Acacia senegal (L) Willd. in Kenya

The level of genetic diversity and population structure of Acacia senegal variety kerensis in Kenya was examined using seven polymorphic nuclear microsatellite loci and two chloroplast microsatellite loci. In both chloroplast and nuclear datasets, high levels of genetic diversity were found within all populations and genetic differentiation among populations was low, indicating extensive gene flow. Analysis of population structure provided support for the presence of two groups of populations, although all individuals had mixed ancestry. Groups reflected the influence of geography on gene flow, with one representing Rift Valley populations whilst the other represented populations from Eastern Kenya. The similarities between estimates derived from nuclear and chloroplast data suggest highly effective gene dispersal by both pollen and seed in this species, although population structure appears to have been influenced by distributional changes in the past. The few contrasts between the spatial patterns for nuclear and chloroplast data provided additional support for the idea that, having fragmented in the past, groups are now thoroughly mixed as a result of extensive gene flow. For the purposes of conservation and in situ management of genetic resources, sampling could target a few, large populations ideally distributed among the spatial groups identified. This should ensure the majority of extant variation is preserved, and facilitate the investigation of variation in important phenotypic traits and development of breeding populations