Population estimators or progeny tests: what is the best method to assess null allele frequencies at SSR loci?

Nuclear SSRs are notorious for having relatively high frequencies of null alleles, i.e. alleles that fail to amplify and are thus recessive and undetected in heterozygotes. In this paper, we compare two kinds of approaches for estimating null allele frequencies at seven nuclear microsatellite markers in three French Fagus sylvatica populations: (1) maximum likelihood methods that compare observed and expected homozygote frequencies in the population under the assumption of Hardy-Weinberg equilibrium and (2) direct null allele frequency estimates from progeny where parent genotypes are known. We show that null allele frequencies are high in F. sylvatica (7.0% on average with the population method, 5.1% with the progeny method), and that estimates are consistent between the two approaches, especially when the number of sampled maternal half-sib progeny arrays is large. With null allele frequencies ranging between 5% and 8% on average across loci, population genetic parameters such as genetic differentiation (F ST) may be mostly unbiased. However, using markers with such average prevalence of null alleles (up to 15% for some loci) can be seriously misleading in fine scale population studies and parentage analysi

Les changements climatiques et leurs effets sur la forêt méditerranéenne : aspects génétiques -

Que peuvent faire les arbres forestiers et leurs écosystèmes en réponse aux changements climatiques qui s'installent sur la longue durée ? Comme tous les organismes vivants, ils peuvent mettre en place trois grandes stratégies : s'acclimater, s'adapter et/ou fuir. Dans cet article, l'auteur nous décrit les différents mécanismes d'adaptation génétique et propose de réfléchir à des pratiques sylvicoles permettant une gestion adaptative de la forêt méditerranéenne

Comment utiliser l’adaptation génétique des arbres dans la gestion forestière ?

Les arbres forestiers, comme tous les êtres vivants, disposent de trois grandes stratégies pour faire face aux crises écologiques comme celle du changement climatique et ne pas disparaître localement ou globalement : la plasticité phénotypique (l’acclimatation), l’adaptation au sens génétique du terme et la migration. Les résultats scientifiques de ces dernières décennies ont bien montré l’importance de ces processus. La question qui se pose actuellement aux scientifiques est de décrire et modéliser conjointement ces processus et la rapidité de leur mise en place. Ces avancées bénéficieront aux gestionnaires en ce début de XXIe siècle qui doivent décider quels risques accepter aujourd’hui pour un environnement climatique de demain qui reste largement inconnu à l’échelle de la parcelle ou du massif forestier

Global to local genetic diversity indicators of evolutionary potential in tree species within and outside forests

There is a general trend of biodiversity loss at global, regional, national and local levels. To monitor this trend, international policy processes have created a wealth of indicators over the last two decades. However, genetic diversity indicators are regrettably absent from comprehensive bio-monitoring schemes. Here, we provide a review and an assessment of the different attempts made to provide such indicators for tree genetic diversity from the global level down to the level of the management unit. So far, no generally accepted indicators have been provided as international standards, nor tested for their possible use in practice. We suggest that indicators for monitoring genetic diversity and dynamics should be based on ecological and demographic surrogates of adaptive diversity as well as genetic markers capable of identifying genetic erosion and gene flow. A comparison of past and present genecological distributions (patterns of genetic variation of key adaptive traits in the ecological space) of selected species is a realistic way of assessing the trend of intra-specific variation, and thus provides a state indicator of tree genetic diversity also able to reflect possible pressures threatening genetic diversity. Revealing benefits of genetic diversity related to ecosystem services is complex, but current trends in plantation performance offer the possibility of an indicator of benefit. Response indicators are generally much easier to define, because recognition and even quantification of, e.g., research, education, breeding, conservation, and regulation actions and programs are relatively straightforward. Only state indicators can reveal genetic patterns and processes, which are fundamental for maintaining genetic diversity. Indirect indicators of pressure, benefit, or response should therefore not be used independently of state indicators. A coherent set of indicators covering diversity–productivity–knowledge–management based on the genecological approach is proposed for application on appropriate groups of tree species in the wild and in cultivation worldwide. These indicators realistically reflect the state, trends and potentials of the world’s tree genetic resources to support sustainable growth. The state of the genetic diversity will be based on trends in population distributions and diversity patterns for selected species. The productivity of the genetic resource of trees in current use will reflect the possible potential of mobilizing the resource further. Trends in knowledge will underpin the potential capacity for development of the resource and current management of the genetic resource itself will reveal how well we are actually doing and where improvements are required

Projecting the potential impact of the Cap-Score™ on Clinical Pregnancy, Live Births, and Medical Costs in Couples with Unexplained Infertility.

Purpose The Cap-Score™ was developed to assess the capacitation status of men, thereby enabling personalized management of unexplained infertility by choosing timed intrauterine insemination (IUI), versus immediate in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in individuals with a low Cap-Score™. The objective of this study was to estimate the differences in outcomes and costs comparing the use of the Cap-Score™ with timed IUI (CS-TI) and the standard of care (SOC), which was assumed to be three IUI cycles followed by three IVF-ICSI cycles. Methods We developed and parameterized a decision-analytic model of management of unexplained infertility for women based on data from the published literature. We calculated the clinical pregnancy rates, live birth rates, and medical costs comparing CS-TI and SOC. We used Monte Carlo simulation to quantify uncertainty in projected estimates and performed univariate sensitivity analysis. Results Compared to SOC, CS-TI was projected to increase the pregnancy rate by 1–26%, marginally reduce live birth rates by 1–3% in couples with women below 40 years, increase live birth rates by 3–7% in couples with women over 40 years, reduce mean medical costs by $4000–$19,200, reduce IUI costs by $600–$1370, and reduce IVF costs by $3400–$17,800, depending on the woman’s age. Conclusion The Cap-Score™ is a potentially valuable clinical tool for management of unexplained infertility because it is projected to improve clinical pregnancy rates, save money, and, depending on the price of the test, increase access to treatment for infertility

Les apports de la recherche scientifique : si l'on a décidé de planter, que planter ?

Si on a décidé de planter, que planter ? Pour donner des éléments de réponse à cette question, revient, en terme de recherche, à mettre en uvre une démarche permettant entre autres, de tester l'adaptation potentielle d'un matériel végétal (espèce, provenance, famille, clone) à son futur milieu d'accueil. Ces résultats ont été obtenus au cousr des 30 dernières années par la mise en place d'un réseau expérimental de plus de 160 placettes sur 16 emplacements pour un total de plus de 450 000 plants d'une quinzaine d'espèces forestières méditerranéennes

Tournée sur les sapins méditerranéens dans le Var

Ce court article décrit la sortie sur le terrain, organisée à la suite des Journées d'études sur les sapins méditerranéens, dans le Var

Les arboretums : un outil de recherche et d'éducation sur la biodiversité forestière Le cas de l'arboretum du Ruscas (Var).

De nombreux arboretums ont été installés en région méditerranéenne française, dans le but de tester la survie et la croissance de différentes espèces et sous-espèces d'arbres forestiers. Nous faisons ici le bilan de l'un d'eux, l'arboretum du Ruscas (Var). Si la croissance et l'adaptation d'espèces, comme le pin laricio, ne surprendra pas, le comportement d'autres espèces, comme Pinus radiata, Quercus ithaburensis ou Alnus subcordata, mérite d'être noté. Au-delà de son intérêt de collection d'arbres remarquables, l'arboretum du Ruscas, comme tous les arboretums, reste un site expérimental d'actualité dans le cadre du suivi de l'effet des changements climatiques, ainsi qu'un outil pédagogique remarquable pour illustrer la complexité de la biodiversité

Pour une gestion évolutive des forêts méditerranéennes face aux changements climatiques

Bruno Fady et Frédéric Médail ont participé au Colloque "Changements climatiques et forêt méditerranéenne". A la suite de ces journées, ils ont souhaité que cette lettre soit publiée. Leur prise de position est très intéressante en addition aux publications de ce numéro, d'autant plus que nous ne pouvons qu'approuver l'idée d'une gestion évolutive des forêts en général et des forêts méditerranéennes en particulier

Extraneural metastases from cranial meningioma: a case report

Extracranial metastases from brain meningiomas is a rare, but well-documented entity. Metastases occur mostly in the lungs, pleura and liver, but may also affect lymph nodes and bones. We report here on a patient who was treated for an atypical brain meningioma with multiple surgeries and multiple sessions of stereotactic radiosurgery with good control of his brain disease. Thirteen years after diagnosis, he developed bilateral large sacroiliac and abdominal metastases