Mapache: a flexible pipeline to map ancient DNA.

SUMMARY: We introduce mapache, a flexible, robust and scalable pipeline to map, quantify and impute ancient and present-day DNA in a reproducible way. Mapache is implemented in the workflow manager Snakemake and is optimized for low-space consumption, allowing to efficiently (re)map large datasets-such as reference panels and multiple extracts and libraries per sample - to one or several genomes. Mapache can easily be customized or combined with other Snakemake tools. AVAILABILITY AND IMPLEMENTATION: Mapache is freely available on GitHub (https://github.com/sneuensc/mapache). An extensive manual is provided at https://github.com/sneuensc/mapache/wiki. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Benchmarking metagenomics classifiers on ancient viral DNA: a simulation study.

Owing to technological advances in ancient DNA, it is now possible to sequence viruses from the past to track down their origin and evolution. However, ancient DNA data is considerably more degraded and contaminated than modern data making the identification of ancient viral genomes particularly challenging. Several methods to characterise the modern microbiome (and, within this, the virome) have been developed; in particular, tools that assign sequenced reads to specific taxa in order to characterise the organisms present in a sample of interest. While these existing tools are routinely used in modern data, their performance when applied to ancient microbiome data to screen for ancient viruses remains unknown. In this work, we conducted an extensive simulation study using public viral sequences to establish which tool is the most suitable to screen ancient samples for human DNA viruses. We compared the performance of four widely used classifiers, namely Centrifuge, Kraken2, DIAMOND and MetaPhlAn2, in correctly assigning sequencing reads to the corresponding viruses. To do so, we simulated reads by adding noise typical of ancient DNA to a set of publicly available human DNA viral sequences and to the human genome. We fragmented the DNA into different lengths, added sequencing error and C to T and G to A deamination substitutions at the read termini. Then we measured the resulting sensitivity and precision for all classifiers. Across most simulations, more than 228 out of the 233 simulated viruses were recovered by Centrifuge, Kraken2 and DIAMOND, in contrast to MetaPhlAn2 which recovered only around one third. Overall, Centrifuge and Kraken2 had the best performance with the highest values of sensitivity and precision. We found that deamination damage had little impact on the performance of the classifiers, less than the sequencing error and the length of the reads. Since Centrifuge can handle short reads (in contrast to DIAMOND and Kraken2 with default settings) and since it achieve the highest sensitivity and precision at the species level across all the simulations performed, it is our recommended tool. Regardless of the tool used, our simulations indicate that, for ancient human studies, users should use strict filters to remove all reads of potential human origin. Finally, we recommend that users verify which species are present in the database used, as it might happen that default databases lack sequences for viruses of interest.

The genomic history of the Aegean palatial civilizations.

The Cycladic, the Minoan, and the Helladic (Mycenaean) cultures define the Bronze Age (BA) of Greece. Urbanism, complex social structures, craft and agricultural specialization, and the earliest forms of writing characterize this iconic period. We sequenced six Early to Middle BA whole genomes, along with 11 mitochondrial genomes, sampled from the three BA cultures of the Aegean Sea. The Early BA (EBA) genomes are homogeneous and derive most of their ancestry from Neolithic Aegeans, contrary to earlier hypotheses that the Neolithic-EBA cultural transition was due to massive population turnover. EBA Aegeans were shaped by relatively small-scale migration from East of the Aegean, as evidenced by the Caucasus-related ancestry also detected in Anatolians. In contrast, Middle BA (MBA) individuals of northern Greece differ from EBA populations in showing ∼50% Pontic-Caspian Steppe-related ancestry, dated at ca. 2,600-2,000 BCE. Such gene flow events during the MBA contributed toward shaping present-day Greek genomes.

Museomics identifies genetic erosion in two butterfly species across the 20th century in Finland.

Erosion of biodiversity generated by anthropogenic activities has been studied for decades and in many areas at the species level, using taxa monitoring. In contrast, genetic erosion within species has rarely been tracked, and is often studied by inferring past population dynamics from contemporaneous estimators. An alternative to such inferences is the direct examination of past genes, by analysing museum collection specimens. While providing direct access to genetic variation over time, historical DNA is usually not optimally preserved, and it is necessary to apply genotyping methods based on hybridization-capture to unravel past genetic variation. In this study, we apply such a method (i.e., HyRAD), to large time series of two butterfly species in Finland, and present a new bioinformatic pipeline, namely PopHyRAD, that standardizes and optimizes the analysis of HyRAD data at the within-species level. In the localities for which the data retrieved have sufficient power to accurately examine genetic dynamics through time, we show that genetic erosion has increased across the last 100 years, as revealed by signatures of allele extinctions and heterozygosity decreases, despite local variations. In one of the two butterflies (Erebia embla), isolation by distance also increased through time, revealing the effect of greater habitat fragmentation over time.

New genome assembly of the barn owl (Tyto alba alba).

New genomic tools open doors to study ecology, evolution, and population genomics of wild animals. For the Barn owl species complex, a cosmopolitan nocturnal raptor, a very fragmented draft genome was assembled for the American species (Tyto furcata pratincola) (Jarvis et al. 2014). To improve the genome, we assembled de novo Illumina and Pacific Biosciences (PacBio) long reads sequences of its European counterpart (Tyto alba alba). This genome assembly of 1.219 Gbp comprises 21,509 scaffolds and results in a N50 of 4,615,526 bp. BUSCO (Universal Single-Copy Orthologs) analysis revealed an assembly completeness of 94.8% with only 1.8% of the genes missing out of 4,915 avian orthologs searched, a proportion similar to that found in the genomes of the zebra finch (Taeniopygia guttata) or the collared flycatcher (Ficedula albicollis). By mapping the reads of the female American barn owl to the male European barn owl reads, we detected several structural variants and identified 70 Mbp of the Z chromosome. The barn owl scaffolds were further mapped to the chromosomes of the zebra finch. In addition, the completeness of the European barn owl genome is demonstrated with 94 of 128 proteins missing in the chicken genome retrieved in the European barn owl transcripts. This improved genome will help future barn owl population genomic investigations.

Characterization and mutagenesis of Chinese hamster ovary cells endogenous retroviruses to inactivate viral particle release.

The Chinese hamster ovary (CHO) cells used to produce biopharmaceutical proteins are known to contain type-C endogenous retrovirus (ERV) sequences in their genome and to release retroviral-like particles. Although evidence for their infectivity is missing, this has raised safety concerns. As the genomic origin of these particles remained unclear, we characterized type-C ERV elements at the genome, transcriptome, and viral particle RNA levels. We identified 173 type-C ERV sequences clustering into three functionally conserved groups. Transcripts from one type-C ERV group were full-length, with intact open reading frames, and cognate viral genome RNA was loaded into retroviral-like particles, suggesting that this ERV group may produce functional viruses. CRISPR-Cas9 genome editing was used to disrupt the gag gene of the expressed type-C ERV group. Comparison of CRISPR-derived mutations at the DNA and RNA level led to the identification of a single ERV as the main source of the release of RNA-loaded viral particles. Clones bearing a Gag loss-of-function mutation in this ERV showed a reduction of RNA-containing viral particle release down to detection limits, without compromising cell growth or therapeutic protein production. Overall, our study provides a strategy to mitigate potential viral particle contaminations resulting from ERVs during biopharmaceutical manufacturing.

Characterization of mesoangioblast cell fate and improved promyogenic potential of a satellite cell-like subpopulation upon transplantation in dystrophic murine muscles.

Duchenne muscular dystrophy (DMD) is a lethal muscle-wasting disease caused by the lack of dystrophin in muscle fibers that is currently without curative treatment. Mesoangioblasts (MABs) are multipotent progenitor cells that can differentiate to a myogenic lineage and that can be used to express Dystrophin upon transplantation into muscles, in autologous gene therapy approaches. However, their fate in the muscle environment remains poorly characterized. Here, we investigated the differentiation fate of MABs following their transplantation in DMD murine muscles using a mass cytometry strategy. This allowed the identification and isolation of a fraction of MAB-derived cells presenting common properties with satellite muscle stem cells. This analysis also indicated that most cells did not undergo a myogenic differentiation path once in the muscle environment, limiting their capacity to restore dystrophin expression in transplanted muscles. We therefore assessed whether MAB treatment with cytokines and growth factors prior to engraftment may improve their myogenic fate. We identified a combination of such signals that ameliorates MABs capacity to undergo myogenic differentiation in vivo and to restore dystrophin expression upon engraftment in myopathic murine muscles.

Impact of deleterious mutations, sexually antagonistic selection, and mode of recombination suppression on transitions between male and female heterogamety.

Deleterious mutations accumulating on non-recombining Y chromosomes can drive XY to XY turnovers, as they allow to replace the old mutation-loaded Y by a new mutation-free one. The same process is thought to prevent XY to ZW turnovers, because the latter requires fixation of the ancestral Y, assuming dominance of the emergent feminizing mutation. Using individual-based simulations, we explored whether and how an epistatically dominant W allele can spread in a young XY system that gradually accumulates deleterious mutations. We also investigated how sexually antagonistic (SA) polymorphism on the ancestral sex chromosomes and the mechanism controlling X-Y recombination suppression affect these transitions. In contrast with XY to XY turnovers, XY to ZW turnovers cannot be favored by Y chromosome mutation load. If the arrest of X-Y recombination depends on genotypic sex, transitions are strongly hindered by deleterious mutations, and totally suppressed by very small SA cost, because deleterious mutations and female-detrimental SA alleles would have to fix with the Y. If, however, the arrest of X-Y recombination depends on phenotypic sex, X and Y recombine in XY ZW females, allowing for the purge of Y-linked deleterious mutations and loss of the SA polymorphism, causing XY to ZW turnovers to occur at the same rate as in the absence of deleterious and sex-antagonistic mutations. We generalize our results to other types of turnovers (e.g., triggered by non-dominant sex-determining mutations) and discuss their empirical relevance.

QuantiNemo 2: a Swiss knife to simulate complex demographic and genetic scenarios, forward and backward in time.

SUMMARY: QuantiNemo 2 is a stochastic simulation program for quantitative population genetics. It was developed to investigate the effects of selection, mutation, recombination and drift on quantitative traits and neutral markers in structured populations connected by migration and located in heterogeneous habitats. A specific feature is that it allows to switch between an individual-based full-featured mode and a population-based faster mode. Several demographic, genetic and selective parameters can be fine-tuned in QuantiNemo 2: population, selection, trait(s) architecture, genetic map for QTL and/or markers, environment, demography and mating system are the main features. AVAILABILITY AND IMPLEMENTATION: QuantiNemo 2 is a C++ program with a source code available under the GNU General Public License version 3. Executables are provided for Windows, MacOS and Linux platforms, together with a comprehensive manual and tutorials illustrating its flexibility. The executable, manual and tutorial can be found on the website www2.unil.ch/popgen/softwares/quantinemo/, while the source code and user support are given through GitHub: github.com/jgx65/quantinemo. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Sex chromosome turnovers and genetic drift: a simulation study.

The recent advances of new genomic technologies have enabled the identification and characterization of sex chromosomes in an increasing number of nonmodel species, revealing that many plants and animals undergo frequent sex chromosome turnovers. What evolutionary forces drive these turnovers remains poorly understood, but it was recently proposed that drift might play a more important role than generally assumed. We analysed the dynamics of different types of turnovers using individual-based simulations and show that when mediated by genetic drift, turnovers are usually easier to achieve than substitutions at neutral markers, but that their dynamics and relative likelihoods vary with the type of the resident and emergent sex chromosome system (XY and/or ZW) and the dominance relationships among the sex-determining factors. Focusing on turnovers driven by epistatically dominant mutations, we find that drift-mediated turnovers that preserve the heterogamety pattern are 2-4× more likely than those along which the heterogametic sex changes. This ratio nevertheless decreases along with effective population size and can even reverse in case of extreme polygyny. This can be attributed to a 'drift-induced' selective force, known to influence transitions between male and female heterogamety, but which according to our study does not affect turnovers that preserve the heterogametic sex.

Complex genetic patterns in human arise from a simple range-expansion model over continental landmasses.

Although it is generally accepted that geography is a major factor shaping human genetic differentiation, it is still disputed how much of this differentiation is a result of a simple process of isolation-by-distance, and if there are factors generating distinct clusters of genetic similarity. We address this question using a geographically explicit simulation framework coupled with an Approximate Bayesian Computation approach. Based on six simple summary statistics only, we estimated the most probable demographic parameters that shaped modern human evolution under an isolation by distance scenario, and found these were the following: an initial population in East Africa spread and grew from 4000 individuals to 5.7 million in about 132 000 years. Subsequent simulations with these estimates followed by cluster analyses produced results nearly identical to those obtained in real data. Thus, a simple diffusion model from East Africa explains a large portion of the genetic diversity patterns observed in modern humans. We argue that a model of isolation by distance along the continental landmasses might be the relevant null model to use when investigating selective effects in humans and probably many other species.

Spatial and temporal genetic dynamics of the grasshopper Oedaleus decorus revealed by museum genomics.

Analyzing genetic variation through time and space is important to identify key evolutionary and ecological processes in populations. However, using contemporary genetic data to infer the dynamics of genetic diversity may be at risk of a bias, as inferences are performed from a set of extant populations, setting aside unavailable, rare, or now extinct lineages. Here, we took advantage of new developments in next-generation sequencing to analyze the spatial and temporal genetic dynamics of the grasshopper Oedaleus decorus, a steppic Southwestern-Palearctic species. We applied a recently developed hybridization capture (hyRAD) protocol that allows retrieving orthologous sequences even from degraded DNA characteristic of museum specimens. We identified single nucleotide polymorphisms in 68 historical and 51 modern samples in order to (i) unravel the spatial genetic structure across part of the species distribution and (ii) assess the loss of genetic diversity over the past century in Swiss populations. Our results revealed (i) the presence of three potential glacial refugia spread across the European continent and converging spatially in the Alpine area. In addition, and despite a limited population sample size, our results indicate (ii) a loss of allelic richness in contemporary Swiss populations compared to historical populations, whereas levels of expected heterozygosities were not significantly different. This observation is compatible with an increase in the bottleneck magnitude experienced by central European populations of O. decorus following human-mediated land-use change impacting steppic habitats. Our results confirm that application of hyRAD to museum samples produces valuable information to study genetic processes across time and space.

The mRNA transportome of the BicD/Egl transport machinery.

mRNA (mRNA) transport focuses the expression of encoded proteins to specific regions within cells providing them with the means to assume specific functions and even identities. BicD and the mRNA binding protein Egl interact with the microtubule motor dynein to localize mRNAs in Drosophila. Because relatively few mRNA cargos were known, we isolated and identified Egl::GFP associated mRNAs. The top candidates were validated by qPCR, in situ hybridization and genetically by showing that their localization requires BicD. In young embryos these Egl target mRNAs are preferentially localized apically, between the plasma membrane and the blastoderm nuclei, but also in the pole plasm at the posterior pole. Egl targets expressed in the ovary were mostly enriched in the oocyte and some were apically localized in follicle cells. The identification of a large group of novel mRNAs associated with BicD/Egl points to several novel developmental and physiological functions of this dynein dependent localization machinery. The verified dataset also allowed us to develop a tool that predicts conserved A'-form-like stem loops that serve as localization elements in 3'UTRs.

MAR-Mediated transgene integration into permissive chromatin and increased expression by recombination pathway engineering.

Untargeted plasmid integration into mammalian cell genomes remains a poorly understood and inefficient process. The formation of plasmid concatemers and their genomic integration has been ascribed either to non-homologous end-joining (NHEJ) or homologous recombination (HR) DNA repair pathways. However, a direct involvement of these pathways has remained unclear. Here, we show that the silencing of many HR factors enhanced plasmid concatemer formation and stable expression of the gene of interest in Chinese hamster ovary (CHO) cells, while the inhibition of NHEJ had no effect. However, genomic integration was decreased by the silencing of specific HR components, such as Rad51, and DNA synthesis-dependent microhomology-mediated end-joining (SD-MMEJ) activities. Genome-wide analysis of the integration loci and junction sequences validated the prevalent use of the SD-MMEJ pathway for transgene integration close to cellular genes, an effect shared with matrix attachment region (MAR) DNA elements that stimulate plasmid integration and expression. Overall, we conclude that SD-MMEJ is the main mechanism driving the illegitimate genomic integration of foreign DNA in CHO cells, and we provide a recombination engineering approach that increases transgene integration and recombinant protein expression in these cells. Biotechnol. Bioeng. 2017;114: 384-396. © 2016 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc.

Maize Cytolines Unmask Key Nuclear Genes That Are under the Control of Retrograde Signaling Pathways in Plants.

The genomes of the two plant organelles encode for a relatively small number of proteins. Thus, nuclear genes encode the vast majority of their proteome. Organelle-to-nucleus communication takes place through retrograde signaling (RS) pathways. Signals relayed through RS pathways have an impact on nuclear gene expression but their target-genes remain elusive in a normal state of the cell (considering that only mutants and stress have been used so far). Here, we use maize cytolines as an alternative. The nucleus of a donor line was transferred into two other cytoplasmic environments through at least nine back-crosses, in a time-span of > 10 years. The transcriptomes of the resulting cytolines were sequenced and compared. There are 96 differentially regulated nuclear genes in two cytoplasm-donor lines when compared with their nucleus-donor. They are expressed throughout plant development, in various tissues and organs. One-third of the 96 proteins have a human homolog, stressing their potential role in mitochondrial RS. We also identified syntenic orthologous genes in four other grasses and homologous genes in Arabidopsis thaliana These findings contribute to the paradigm we use to describe the RS in plants. The 96 nuclear genes identified here are not differentially regulated as a result of mutation, or any kind of stress. They are rather key players of the organelle-to-nucleus communication in a normal state of the cell.

Reconstructing the demographic history of divergence between European river and brook lampreys using approximate Bayesian computations.

Inferring the history of isolation and gene flow during species divergence is a central question in evolutionary biology. The European river lamprey (Lampetra fluviatilis) and brook lamprey (L. planeri) show a low reproductive isolation but have highly distinct life histories, the former being parasitic-anadromous and the latter non-parasitic and freshwater resident. Here we used microsatellite data from six replicated population pairs to reconstruct their history of divergence using an approximate Bayesian computation framework combined with a random forest model. In most population pairs, scenarios of divergence with recent isolation were outcompeted by scenarios proposing ongoing gene flow, namely the Secondary Contact (SC) and Isolation with Migration (IM) models. The estimation of demographic parameters under the SC model indicated a time of secondary contact close to the time of speciation, explaining why SC and IM models could not be discriminated. In case of an ancient secondary contact, the historical signal of divergence is lost and neutral markers converge to the same equilibrium as under the less parameterized model allowing ongoing gene flow. Our results imply that models of secondary contacts should be systematically compared to models of divergence with gene flow; given the difficulty to discriminate among these models, we suggest that genome-wide data are needed to adequately reconstruct divergence history.

Genome-wide prediction methods in highly diverse and heterozygous species: proof-of-concept through simulation in grapevine.

Nowadays, genome-wide association studies (GWAS) and genomic selection (GS) methods which use genome-wide marker data for phenotype prediction are of much potential interest in plant breeding. However, to our knowledge, no studies have been performed yet on the predictive ability of these methods for structured traits when using training populations with high levels of genetic diversity. Such an example of a highly heterozygous, perennial species is grapevine. The present study compares the accuracy of models based on GWAS or GS alone, or in combination, for predicting simple or complex traits, linked or not with population structure. In order to explore the relevance of these methods in this context, we performed simulations using approx 90,000 SNPs on a population of 3,000 individuals structured into three groups and corresponding to published diversity grapevine data. To estimate the parameters of the prediction models, we defined four training populations of 1,000 individuals, corresponding to these three groups and a core collection. Finally, to estimate the accuracy of the models, we also simulated four breeding populations of 200 individuals. Although prediction accuracy was low when breeding populations were too distant from the training populations, high accuracy levels were obtained using the sole core-collection as training population. The highest prediction accuracy was obtained (up to 0.9) using the combined GWAS-GS model. We thus recommend using the combined prediction model and a core-collection as training population for grapevine breeding or for other important economic crops with the same characteristics.

Natural selection in a postglacial range expansion: the case of the colour cline in the European barn owl.

Gradients of variation--or clines--have always intrigued biologists. Classically, they have been interpreted as the outcomes of antagonistic interactions between selection and gene flow. Alternatively, clines may also establish neutrally with isolation by distance (IBD) or secondary contact between previously isolated populations. The relative importance of natural selection and these two neutral processes in the establishment of clinal variation can be tested by comparing genetic differentiation at neutral genetic markers and at the studied trait. A third neutral process, surfing of a newly arisen mutation during the colonization of a new habitat, is more difficult to test. Here, we designed a spatially explicit approximate Bayesian computation (ABC) simulation framework to evaluate whether the strong cline in the genetically based reddish coloration observed in the European barn owl (Tyto alba) arose as a by-product of a range expansion or whether selection has to be invoked to explain this colour cline, for which we have previously ruled out the actions of IBD or secondary contact. Using ABC simulations and genetic data on 390 individuals from 20 locations genotyped at 22 microsatellites loci, we first determined how barn owls colonized Europe after the last glaciation. Using these results in new simulations on the evolution of the colour phenotype, and assuming various genetic architectures for the colour trait, we demonstrate that the observed colour cline cannot be due to the surfing of a neutral mutation. Taking advantage of spatially explicit ABC, which proved to be a powerful method to disentangle the respective roles of selection and drift in range expansions, we conclude that the formation of the colour cline observed in the barn owl must be due to natural selection.

Wheat alleles introgress into selfing wild relatives: empirical estimates from approximate Bayesian computation in Aegilops triuncialis.

Extensive gene flow between wheat (Triticum sp.) and several wild relatives of the genus Aegilops has recently been detected despite notoriously high levels of selfing in these species. Here, we assess and model the spread of wheat alleles into natural populations of the barbed goatgrass (Aegilops triuncialis), a wild wheat relative prevailing in the Mediterranean flora. Our sampling, based on an extensive survey of 31 Ae. triuncialis populations collected along a 60 km × 20 km area in southern Spain (Grazalema Mountain chain, Andalousia, totalling 458 specimens), is completed with 33 wheat cultivars representative of the European domesticated pool. All specimens were genotyped with amplified fragment length polymorphism with the aim of estimating wheat admixture levels in Ae. triuncialis populations. This survey first confirmed extensive hybridization and backcrossing of wheat into the wild species. We then used explicit modelling of populations and approximate Bayesian computation to estimate the selfing rate of Ae. triuncialis along with the magnitude, the tempo and the geographical distance over which wheat alleles introgress into Ae. triuncialis populations. These simulations confirmed that extensive introgression of wheat alleles (2.7 × 10(-4) wheat immigrants for each Ae. triuncialis resident, at each generation) into Ae. triuncialis occurs despite a high selfing rate (Fis ≈ 1 and selfing rate = 97%). These results are discussed in the light of risks associated with the release of genetically modified wheat cultivars in Mediterranean agrosystems.

Regulation of 11ß-hydroxysteroid dehydrogenase type 2 by microRNA.

The enzyme 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2) is selectively expressed in aldosterone target tissues, conferring aldosterone selectivity for the mineralocorticoid receptor. A diminished activity causes salt-sensitive hypertension. The mechanism of the variable and distinct 11ß-hydroxysteroid dehydrogenase type 2 gene (HSD11B2) expression in the cortical collecting duct is poorly understood. Here, we analyzed for the first time whether the 11ß-HSD2 expression is modulated by microRNAs (miRNAs). In silico analysis revealed 53 and 27 miRNAs with potential binding sites on human or rat HSD11B2 3'-untranslated region. A reporter assay demonstrated 3'-untranslated region-dependent regulation of human and rodent HSD11B2. miRNAs were profiled from cortical collecting ducts and proximal convoluted tubules. Bioinformatic analyses showed a distinct clustering for cortical collecting ducts and proximal convoluted tubules with 53 of 375 miRNAs, where 13 were predicted to bind to the rat HSD11B2 3'-untranslated region. To gain insight into potentially relevant miRNAs in vivo, we investigated 2 models with differential 11ß-HSD2 activity linked with salt-sensitive hypertension. (1) Comparing Sprague-Dawley with low and Wistar rats with high 11ß-HSD2 activity revealed rno-miR-20a-5p, rno-miR-19b-3p, and rno-miR-190a-5p to be differentially expressed. (2) Uninephrectomy lowered 11ß-HSD2 activity in the residual kidney with differentially expressed rno-miR-19b-3p, rno-miR-29b-3p, and rno-miR-26-5p. In conclusion, miRNA-dependent mechanisms seem to modulate 11ß-HSD2 dosage in health and disease states.