Molecular Loci Research Articles

Optimizing the widely used nuclear protein-coding gene primers in beetle phylogenies and their application in the genus Sasajiscymnus Vandenberg (Coleoptera: Coccinellidae).

Advances in genomic biology and the increasing availability of genomic resources allow developing hundreds of nuclear protein‐coding (NPC) markers, which can be used in phylogenetic research. However, for low taxonomic levels, it may be more practical to select a handful of suitable molecular loci for phylogenetic inference. Unfortunately, the presence of degenerate primers of NPC markers can be a major impediment, as the amplification success rate is low and they tend to amplify nontargeted regions. In this study, we optimized five NPC fragments widely used in beetle phylogenetics (i.e., two parts of carbamoyl‐phosphate synthetase: CADXM and CADMC, Topoisomerase, Wingless and Pepck) by reducing the degenerate site of primers and the length of target genes slightly. These five NPC fragments and 6 other molecular loci were amplified to test the monophyly of the coccinellid genus Sasajiscymnus Vandenberg. The analysis of our molecular data set clearly supported the genus Sasajiscymnus may be monophyletic but confirmation with an extended sampling is required. A fossil‐calibrated chronogram was generated by BEAST, indicating an origin of the genus at the end of the Cretaceous (77.87 Myr). Furthermore, a phylogenetic informativeness profile was generated to compare the phylogenetic properties of each gene more explicitly. The results showed that COI provides the strongest phylogenetic signal among all the genes, but Pepck, Topoisomerase, CADXM and CADMC are also relatively informative. Our results provide insight into the evolution of the genus Sasajiscymnus, and also enrich the molecular data resources for further study.

Rapid adaptive evolution of the diapause program during range expansion of an invasive mosquito.

In temperate climates, the recurring seasonal exigencies of winter represent a fundamental physiological challenge for a wide range of organisms. In response, many temperate insects enter diapause, an alternative developmental program, including developmental arrest, that allows organisms to synchronize their life cycle with seasonal environmental variation. Geographic variation in diapause phenology contributing to local climatic adaptation is well documented. However, few studies have examined how the rapid evolution of a suite of traits expressed across the diapause program may contribute to climatic adaptation on a contemporary timescale. Here, we investigate the evolution of the diapause program over the past 35 years by leveraging a “natural experiment” presented by the recent invasion of the Asian tiger mosquito, Aedes albopictus, across the eastern United States. We sampled populations from two distinct climatic regions separated by 6° of latitude (∼700 km). Using common‐garden experiments, we identified regional genetic divergence in diapause‐associated cold tolerance, diapause duration, and postdiapause starvation tolerance. We also found regional divergence in nondiapause thermal performance. In contrast, we observed minimal regional divergence in nondiapause larval growth traits and at neutral molecular marker loci. Our results demonstrate rapid evolution of the diapause program and imply strong selection caused by differences in winter conditions.

A fully joint Bayesian quantitative trait locus mapping of human protein abundance in plasma.

Molecular quantitative trait locus (QTL) analyses are increasingly popular to explore the genetic architecture of complex traits, but existing studies do not leverage shared regulatory patterns and suffer from a large multiplicity burden, which hampers the detection of weak signals such as trans associations. Here, we present a fully multivariate proteomic QTL (pQTL) analysis performed with our recently proposed Bayesian method LOCUS on data from two clinical cohorts, with plasma protein levels quantified by mass-spectrometry and aptamer-based assays. Our two-stage study identifies 136 pQTL associations in the first cohort, of which >80% replicate in the second independent cohort and have significant enrichment with functional genomic elements and disease risk loci. Moreover, 78% of the pQTLs whose protein abundance was quantified by both proteomic techniques are confirmed across assays. Our thorough comparisons with standard univariate QTL mapping on (1) these data and (2) synthetic data emulating the real data show how LOCUS borrows strength across correlated protein levels and markers on a genome-wide scale to effectively increase statistical power. Notably, 15% of the pQTLs uncovered by LOCUS would be missed by the univariate approach, including several trans and pleiotropic hits with successful independent validation. Finally, the analysis of extensive clinical data from the two cohorts indicates that the genetically-driven proteins identified by LOCUS are enriched in associations with low-grade inflammation, insulin resistance and dyslipidemia and might therefore act as endophenotypes for metabolic diseases. While considerations on the clinical role of the pQTLs are beyond the scope of our work, these findings generate useful hypotheses to be explored in future research; all results are accessible online from our searchable database. Thanks to its efficient variational Bayes implementation, LOCUS can analyze jointly thousands of traits and millions of markers. Its applicability goes beyond pQTL studies, opening new perspectives for large-scale genome-wide association and QTL analyses.Diet, Obesity and Genes (DiOGenes) trial registration number: NCT00390637.

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Genome Sequencing of the Endangered Kingdonia uniflora (Circaeasteraceae, Ranunculales) Reveals Potential Mechanisms of Evolutionary Specialization.

SummaryKingdonia uniflora, an alpine herb, has an extremely narrow distribution and represents a model for studying evolutionary mechanisms of species that have adapted to undisturbed environments for evolutionarily long periods of time. We assembled a 1,004.7-Mb draft genome (encoding 43,301 genes) of K. uniflora and found significant overrepresentation in gene families associated with DNA repair, underrepresentation in gene families associated with stress response, and loss of most plastid ndh genes. During the evolutionary process, the overrepresentation of gene families involved in DNA repair could help asexual K. uniflora reduce the accumulation of deleterious mutations, while reducing genetic diversity, which is important in responding to environment fluctuations. The underrepresentation of gene families related to stress response and functional loss of ndh genes could be due to lack or loss of ability to respond to environmental changes caused by long-term adaptation to a relatively stable ecological environment.

Let’s makePulvigeragreat again: re-circumscription of a misunderstood group of Orthotrichaceae that diversified in North America

AbstractOrthotrichum lyellii was described in 1878 based on the crisped leaves with plane margins on its elongated and branched stems, and on the presence of brood-bodies. In Europe, these characters remain constant, but in North America several similar forms lacking propagules have been described either at the specific or infraspecific level. These were all reduced to synonyms of O. lyellii. In 2015, Orthotrichum was divided, and O. lyellii was transferred to Pulvigera, a genus thus far considered to be monospecific. In this study, the variability of P. lyellii is analysed in an integrative taxonomic framework. Morphological studies on > 200 specimens, including the nomenclatural types of the taxa previously described, were combined with biogeographical and ecological evidence and with a phylogenetic reconstruction of 39 terminals based on five molecular loci. All the sources of evidence suggest the existence of four different taxa in North America, one also present on the Marquesas Islands. The study of type materials led to their identification as P. lyellii and three other taxa previously described from North America, Orthotrichum papillosum, O. lyellii var. howei and O. pringlei. These taxa differ from each other in taxonomically significant morphological characters of the gametophyte and sporophyte. The morphological diversity has led us to reinterpret Pulvigera, and to amend its description. Nomenclatural changes for the reinstated taxa are proposed, and full descriptions and an identification key for Pulvigera spp. in North America are provided.

Intraspecific Genetic Variation Underlying Postmating Reproductive Barriers between Species in the Wild Tomato Clade (Solanum sect. Lycopersicon)

A goal of speciation genetics is to understand how the genetic components underlying interspecific reproductive barriers originate within species. Unilateral incompatibility (UI) is a postmating prezygotic barrier in which pollen rejection in the female reproductive tract (style) occurs in only one direction of an interspecific cross. Natural variation in the strength of UI has been observed among populations within species in the wild tomato clade. In some cases, molecular loci underlying self-incompatibility (SI) are associated with this variation in UI, but the mechanistic connection between these intra- and inter-specific pollen rejection behaviors is poorly understood in most instances. We generated an F2 population between SI and SC genotypes of a single species, Solanum pennellii, to examine the genetic basis of intraspecific variation in UI against other species, and to determine whether loci underlying SI are genetically associated with this variation. We found that F2 individuals vary in the rate at which UI rejection occurs. One large effect QTL detected for this trait co-localized with the SI-determining S-locus. Moreover, individuals that expressed S-RNase-the S-locus protein involved in SI pollen rejection-in their styles had much more rapid UI responses compared with those without S-RNase protein. Our analysis shows that intraspecific variation at mate choice loci-in this case at loci that prevent self-fertilization-can contribute to variation in the expression of interspecific isolation, including postmating prezygotic barriers. Understanding the nature of such intraspecific variation can provide insight into the accumulation of these barriers between diverging lineages.

Characterisation of the impact of inhibition on STR profiles: Causes, mechanisms and consequences

Inhibition of the polymerase chain reaction can jeopardise the success of STR genotyping. A number of studies exist that have looked at the impact of inhibitors on STR profiling; these generally look at the broad impact of inhibition, such as the number of peaks observed, average peak height and profile success. This study investigates inhibition in more detail by comparing patterns of inhibition with known characteristics of an STR kit. By looking at the balance of the loci within STR profiles under different inhibitory conditions and assessing the impact of altering PCR conditions such as annealing temperature on locus performance, hypotheses of inhibitory mechanisms can be formed. The data show that a number of inhibitory mechanisms could be identified. Some of these appeared to be associated with primer annealing, where loci with primers with lower annealing temperatures were observed to be inhibited more than loci with primers with higher annealing temperatures. Other inhibitors appeared to impact on the processivity of the polymerase enzyme affecting high molecular weight loci more than low molecular weight loci; this produces an effect similar to degradation with the classic “ski-slope” pattern. These data can be used to inform what inhibitors may be present within a sample for troubleshooting purposes. Additionally, these data provide information that can be used to improve primer design for improved inhibitor tolerance.

Analyses of inter-individual variations of sperm DNA methylation and their potential implications in cattle

BackgroundDNA methylation has been shown to be involved in many biological processes, including X chromosome inactivation in females, paternal genomic imprinting, and others.ResultsBased on the correlation patterns of methylation levels of neighboring CpG sites among 28 sperm whole genome bisulfite sequencing (WGBS) data (486 × coverage), we obtained 31,272 methylation haplotype blocks (MHBs). Among them, we defined conserved methylated regions (CMRs), variably methylated regions (VMRs) and highly variably methylated regions (HVMRs) among individuals, and showed that HVMRs might play roles in transcriptional regulation and function in complex traits variation and adaptive evolution by integrating evidence from traditional and molecular quantitative trait loci (QTL), and selection signatures. Using a weighted correlation network analysis (WGCNA), we also detected a co-regulated module of HVMRs that was significantly associated with reproduction traits, and enriched for glycosyltransferase genes, which play critical roles in spermatogenesis and fertilization. Additionally, we identified 46 VMRs significantly associated with reproduction traits, nine of which were regulated by cis-SNPs, implying the possible intrinsic relationships among genomic variations, DNA methylation, and phenotypes. These significant VMRs were co-localized (± 10 kb) with genes related to sperm motility and reproduction, including ZFP36L1, CRISP2 and HGF. We provided further evidence that rs109326022 within a predominant QTL on BTA18 might influence the reproduction traits through regulating the methylation level of nearby genes JOSD2 and ASPDH in sperm.ConclusionIn summary, our results demonstrated associations of sperm DNA methylation with reproduction traits, highlighting the potential of epigenomic information in genomic improvement programs for cattle.

Resolving relationships in an exceedingly young Neotropical orchid lineage using Genotyping-by-sequencing data

Poor morphological and molecular differentiation in recently diversified lineages is a widespread phenomenon in plants. Phylogenetic relationships within such species complexes are often difficult to resolve because of the low variability in traditional molecular loci. Furthermore, biological phenomena responsible for topological incongruence such as Incomplete Lineage Sorting (ILS) and hybridisation complicate the resolution of phylogenetic relationships among closely related taxa. In this study, we employ a Genotyping-by-sequencing (GBS) approach to disentangle evolutionary relationships within a species complex belonging to the Neotropical orchid genus Cycnoches. This complex includes seven taxa distributed through Central America and the Colombian Chocó, and is nested within a clade estimated to have first diversified in the early Quaternary. Previous phylogenies inferred from few loci failed to provide support for internal relationships within the complex. Our Neighbour-net and coalescent-based analyses inferred from ca. 13,000 GBS loci obtained from 31 individuals belonging to six of the seven traditionally accepted Cycnoches taxa provided a robust phylogeny for this group. The genus Cycnoches includes three main clades that are further supported by morphological traits and geographic distributions. Similarly, a topology reconstructed through maximum likelihood (ML) inference of concatenated GBS loci produced results that are comparable with those reconstructed through coalescence and network-based methods. Our comparative phylogenetic informativeness analyses suggest that the low support evident in the ML phylogeny might be attributed to the abundance of uninformative GBS loci, which can account for up to 50% of the total number of loci recovered. The phylogenomic framework provided here, as well as morphological evidence and geographical patterns, suggest that the six entities previously thought to be different species or subspecies might actually represent only three distinct segregates. We further discuss the limited phylogenetic informativeness found in our GBS approach and its utility to disentangle relationships within recent and rapidly evolving species complexes. Our study is the first to demonstrate the utility of GBS data to reconstruct relationships within young (~2 Ma) Neotropical plant clades, opening new avenues for studies of species complexes that populate the species-rich orchid family.

Rain forest shifts through time and riverine barriers shaped the diversification of South American terrestrial pit vipers (Bothrops jararacussu species group)

AbstractAimTo investigate (a) historical biogeographical connections and species interchange among rain forest habitats and (b) the role of riverine barriers on population divergence and speciation in the Neotropical region.LocationAmazonia and Atlantic Forest in South America.TaxonBothrops jararacussu species group (Serpentes: Viperidae).MethodsWe inferred phylogenetic relationships within Bothrops with an emphasis on the jararacussu species group under a Bayesian framework based on six molecular loci. We also used genetic coalescent simulations and approximate Bayesian computation to infer historical demography within the jararacussu group based on tests of alternative scenarios.ResultsWe found the jararacussu species group to be monophyletic. The Atlantic Forest species B. pirajai and B. muriciensis were inferred nested within this group, closely related to B. jararacussu, confirming that Atlantic Forest species form a clade. The historical demographic analyses support vicariant separation between populations of B. brazili north and south of the Amazon River during the Miocene–Pliocene border, as well as colonization of the Atlantic Forest by a northern Amazonian ancestor in the Pleistocene.Main ConclusionThe evolutionary history of the jararacussu species group sheds light on the dynamism of Neotropical rain forests over time, with at least one event of forest expansion leading to faunal interchange between Amazonian and Atlantic forests in the Pleistocene. Moreover, tests of alternative demographic scenarios suggest that the populations of B. brazili from north and south of the Amazon River originated from a vicariant event during the Miocene–Pliocene border, in agreement with the proposed age of establishment of the modern Amazon River drainage. Our results also have taxonomic implications for these medically important venomous snakes, supporting unrecognized diversity at the species level.

IFunMed: Integrative functional mediation analysis of GWAS and eQTL studies.

Genome-wide association studies (GWAS) have successfully identified thousands of genetic variants contributing to disease and other phenotypes. However, significant obstacles hamper our ability to elucidate causal variants, identify genes affected by causal variants, and characterize the mechanisms by which genotypes influence phenotypes. The increasing availability of genome-wide functional annotation data is providing unique opportunities to incorporate prior information into the analysis of GWAS to better understand the impact of variants on disease etiology. Although there have been many advances in incorporating prior information into prioritization of trait-associated variants in GWAS, functional annotation data have played a secondary role in the joint analysis of GWAS and molecular (i.e., expression) quantitative trait loci (eQTL) data in assessing evidence for association. To address this, we develop a novel mediation framework, iFunMed, to integrate GWAS and eQTL data with the utilization of publicly available functional annotation data. iFunMed extends the scope of standard mediation analysis by incorporating information from multiple genetic variants at a time and leveraging variant-level summary statistics. Data-driven computational experiments convey how informative annotations improve single-nucleotide polymorphism (SNP) selection performance while emphasizing robustness of iFunMed to noninformative annotations. Application to Framingham Heart Study data indicates that iFunMed is able to boost detection of SNPs with mediation effects that can be attributed to regulatory mechanisms.

Genetic Insights Into Smooth Muscle Cell Contributions to Coronary Artery Disease.

Coronary artery disease is a complex cardiovascular disease involving an interplay of genetic and environmental influences over a lifetime. Although considerable progress has been made in understanding lifestyle risk factors, genetic factors identified from genome-wide association studies may capture additional hidden risk undetected by traditional clinical tests. These genetic discoveries have highlighted many candidate genes and pathways dysregulated in the vessel wall, including those involving smooth muscle cell phenotypic modulation and injury responses. Here, we summarize experimental evidence for a few genome-wide significant loci supporting their roles in smooth muscle cell biology and disease. We also discuss molecular quantitative trait locus mapping as a powerful discovery and fine-mapping approach applied to smooth muscle cell and coronary artery disease-relevant tissues. We emphasize the critical need for alternative genetic strategies, including cis/trans-regulatory network analysis, genome editing, and perturbations, as well as single-cell sequencing in smooth muscle cell tissues and model organisms, under both normal and disease states. By integrating multiple experimental and analytical modalities, these multidimensional datasets should improve the interpretation of coronary artery disease genome-wide association studies and molecular quantitative trait locus signals and inform candidate targets for therapeutic intervention or risk prediction.

Phylogeny of Coussareeae (Rubioideae, Rubiaceae)

Coussareeae are a Neotropical clade of morphologically heterogeneous plants in the subfamily Rubioideae of the coffee family (Rubiaceae). The tribe encompasses about 330 species assigned to ten genera: Bradea, Coccocypselum, Coussarea, Cruckshanksia, Declieuxia, Faramea, Heterophyllaea, Hindsia, Oreopolus, and Standleya. Historically, the genera of Coussareeae have rarely been considered closely related, and the widely defined Coussareeae were delimited based on molecular systematics without proposed morphological synapomorphies. In order to assess the tribe’s monophyly, as well as the generic limits, infrageneric relationships, and suprageneric relationships, multiple specimens per genus were sampled whenever possible and analyzed using multiple molecular loci with the Bayesian and maximum likelihood methods. The results of the phylogenetic analyses (all genera represented by multiple terminals are monophyletic, all genera are resolved with respect to each other, and three major suprageneric clades are resolved), coupled with herbarium and literature studies, were used to identify potential synapomorphic features. Non-molecular diagnostic features remain elusive for Coussareeae as a whole, but we have identified multiple diagnostic features and potential synapomorphies for each of the three major suprageneric clades: (1) Coussarea and Faramea (e.g., porate pollen grains with annuli bordering the pores); (2) Bradea, Coccocypselum, Declieuxia, Hindsia, and Standleya (e.g., colporate pollen grains with complex reticulate tecta); and 3) Cruckshanksia, Heterophyllaea, and Oreopolus (e.g., chartaceous, loculicidal capsules). The latter clade, distributed in different biomes of the Andes, is sister to the former two, both widely distributed in the Neotropics.

Insight on Rosaceae Family with Genome Sequencing and Functional Genomics Perspective.

Rosaceae is one of the important families possessing a variety of diversified plant species. It includes many economically valuable crops that provide nutritional and health benefits for the human. Whole genome sequences of valuable crop plants were released in recent years. Understanding of genomics helps to decipher the plant physiology and developmental process. With the information of cultivating species and its wild relative genomes, genome sequence-based molecular markers and mapping loci for economically important traits can be used to accelerate the genome assisted breeding. Identification and characterization of disease resistant capacities and abiotic stress tolerance related genes are feasible to study across species with genome information. Further breeding studies based on the identification of gene loci for aesthetic values, flowering molecular circuit controls, fruit firmness, nonacid fruits, etc. is required for producing new cultivars with valuable traits. This review discusses the whole genome sequencing reports of Malus, Pyrus, Fragaria, Prunus, and Rosa and status of functional genomics of representative traits in individual crops.

Meloidogyne aegracyperi n. sp. (Nematoda: Meloidogynidae), a root-knot nematode parasitizing yellow and purple nutsedge in New Mexico.

Meloidogyne aegracyperi n. sp. is described from roots of purple nutsedge in southern New Mexico, USA. Mature females are small (310–460 µm), pearly white, with their egg masses completely contained inside root galls. The neck is often at a 90 to 130° angle to the protruding posterior end with the perineal pattern. The distance of the dorsal esophageal gland orifice (DGO) to the base of the stylet is relatively long (4.0–6.1 µm), and the excretory pore is level with the base of the stylet. The anterior portion of the rounded lumen lining of the metacorpus contains 3 to 10 small vesicles. The perineal pattern has a rounded dorsal arch with a tail terminal area that is smooth or marked with rope-like striae. Only two males were found. The body twists 90° throughout its length. The DGO to the base of the stylet is long (3.0–3.3) µm. The cephalic framework of the second-stage juvenile is weak, and the stylet is short (10.1–11.8 µm). The DGO to the base of the stylet is long (3–5 µm). The tail is very long (64–89 µm) and the hyaline portion of the tail is very narrow, making the tail finely pointed. Eggs are typical for the genus and vary in length (85.2–99.8 µm) and width (37.1–48.1 µm), having a L/W ratio of (2.1–2.6). Maximum likelihood phylogenetic analyses of the different molecular loci (partial 18S rRNA, D2-D3 of 28S rRNA, internal transcribed spacer (ITS) rRNA, cytochrome oxidase subunit II (COII)-16S rRNA of mitochondrial DNA gene fragments and partial Hsp90 gene) placed this nematode on an independent branch in between M. graminicola and M. naasi and a cluster of species containing M. chitwoodi. M. fallax, and M. minor. Greenhouse tests showed that yellow and purple nutsedge were the best hosts, but perennial ryegrass, wheat, bentgrass, and barley were also hosts.

Phylogeny of the Echinoderes coulli-group (Kinorhyncha : Cyclorhagida : Echinoderidae) – a cosmopolitan species group trapped in the intertidal

Kinorhyncha is a phylum of microscopic, benthic marine invertebrates found throughout the world, from the Arctic to Antarctica and from the intertidal zone to the deep sea. Within the most species-rich genus, Echinoderes, we find a putatively monophyletic species group, the so-called Echinoderes coulli-group. The remarkable morphological similarities of the E. coulli-group species and the fact that the group has a global distribution even though most of the species are restricted to intertidal habitats, has led to the hypothesis that dispersal and speciation within the group has been driven by the process of continental drift. However, this has never been confirmed empirically. With morphology and two molecular loci, COI and 18S, we calculated phylogenetic trees by analysing datasets separately and in combination using Maximum Parsimony, Maximum Likelihood and Bayesian Inference. Using different models of evolution in combination with different statistical approaches, we show that two major clade divergences were consistent with historic drifting of continents, suggesting that vicariance has played an important role for the speciation within the E. coulli-group. Furthermore, we found that reconstructions of past tectonic drifting since the Devonian (416–359 million years ago) were able to explain present species distributions, and suggest that the group originated in a supposedly vast shallow marine environment in north-eastern Gondwana by the mid-late Silurian, 426–416 million years ago.

Glycosylation of Type I Collagen.

Fibrillar type I collagen is the most abundant structural protein in most tissues and organs. One of the unique and functionally important characteristics of collagen is sequential posttranslational modifications of lysine (Lys) residues. In the endoplasmic reticulum, hydroxylation of specific Lys occurs producing 5-hydroxylysine (Hyl). Then, to the 5-hydroxyl group of Hyl, a single galactose unit can be attached to form galactosyl-Hyl (Gal-Hyl) and further glucose can be added to Gal-Hyl to form glucosylgalactosyl-Hyl (GlcGal-Hyl). These are the only two O-linked glycosides found in mature type I collagen. It has been shown that this modification is critically involved in a number of biological and pathological processes likely through its regulatory roles in collagen fibrillogenesis, intermolecular cross-linking, and collagen-cell interaction. Recently, with the advances in molecular/cell biology and analytical chemistry, the molecular mechanisms of collagen glycosylation have been gradually deciphered, and the type and extent of glycosylation at the specific molecular loci can now be quantitatively analyzed. In this chapter, we describe quantitative analysis of collagen glycosylation by high-performance liquid chromatography (HPLC) and semiquantitative, site-specific analysis by HPLC-tandem mass spectrometry.

Multiple independent origins of intermediate species between Sorbus aucuparia and S. hybrida (Rosaceae) in the Baltic region

Populations intermediate between the diploid and sexual Sorbus aucuparia and the tetraploid and facultative apomictic Sorbus hybrida are scattered in coastal regions of southern Scandinavia. Our aims were to investigate whether these populations were of local and independent origins, whether they were morphologically and molecularly distinct from each other and whether they could give rise to constant offspring by apomixis. Six intermediate populations from the Baltic Sea basin were studied for variation at nuclear and plastid microsatellite loci, for morphological differentiation patterns, and for ploidy level by flow cytometry. Seeds were sown to check for constancy with the mother plants. Three populations from Gotland and possibly the small population from Uppland were in each case fixed for a unique combination of genetic markers, had restricted variation in leaf shape and were morphologically divergent from each other. Flow cytometry analysis showed that the four genetically monomorphic populations were consistently triploid. Cultivation showed that offspring from trees within two of the monomorphic populations had leaf shapes closely similar to the mother individuals. In contrast, a population from Gotland and a population from Åland were variable at molecular marker loci and were variable in leaf shape. The three monomorphic Gotland populations and possibly also the Uppland population propagate asexually by apomixis, and they have independent origins. The two variable populations are apparently composed of hybrids that have been formed repeatedly and independently between individuals of the two parental species growing at the same sites. One of the Gotland apomicts has already been described as Sorbus teodori. Sorbus faohraei Hedrén & J.Levin and Sorbus atrata Hedrén & J.Levin are described as new apomictic species from Gotland.

Fountain of youth for squamous cell carcinomas? On the epigenetic age of non-small cell lung cancer and corresponding tumor-free lung tissues.

Aging affects the core processes of almost every organism, and the functional decline at the cellular and tissue levels influences disease development. Recently, it was shown that the methylation of certain CpG dinucleotides correlates with chronological age and that this epigenetic clock can be applied to study aging‐related effects. We investigated these molecular age loci in non‐small cell lung cancer (NSCLC) tissues from patients with adenocarcinomas (AC) and squamous cell carcinomas (SQC) as well as in matched tumor‐free lung tissue. In both NSCLC subtypes, the calculated epigenetic age did not correlate with the chronological age. In particular, SQC exhibited rejuvenation compared to the corresponding normal lung tissue as well as with the chronological age of the donor. Moreover, the younger epigenetic pattern was associated with a trend toward stem cell‐like gene expression patterns. These findings show deep phenotypic differences between the tumor entities AC and SQC, which might be useful for novel therapeutic and diagnostic approaches.