Search

The worldwide distributed subfamily of rove beetles Silphinae contains two well‐established tribes, based on both morphological and molecular data. The relationships within the tribe Nicrophorini have been mostly resolved; however, the tribe Silphini still lacks a robust phylogeny. Thus, here we resolved the phylogeny of the tribe based on 42 species of the 114 known species, using five molecular markers. Heterotemna tenuicornis Brullé clustered as sister to Silpha tristis Illiger, making the subgenus Silpha Linnaeus paraphyletic. Consequently, Heterotemna Wollaston is considered a junior subjective synonym of Silpha Linnaeus; requiring the following combinations: Silpha (Silpha) britoi (García & Pérez), comb. nov., Silpha (Silpha) figurata Brullé, comb. rest., and Silpha (Silpha) tenuicornis Brullé, comb. rest. Our estimate of the phylogeny agrees with current generic limits except it revealed that the genus Aclypea Reitter arose from within the genus Silpha, thus making the latter paraphyletic. Some ambiguity remains regarding the confidence of this finding; therefore, we refrain from synonymizing Aclypea until further study. Furthermore, it includes biogeographical information for each genus, which estimates the history of distributions of the Silphini across the Australian, Neotropical, and Oriental regions. [ABSTRACT FROM AUTHOR]

Aim: The Holocene history of annual plant species is at best shadowy because, for most, the palaeobotanical data are scarce or absent. Hence, there is limited information on their glacial refugia and postglacial colonization pathways. Also, little is known on how human activity has affected their expansion. Here, we outline the joint influences of postglacial colonization and recent expansions on the genetic diversity of the continental, sub‐halophyte species Atriplex tatarica during the late Pleistocene and the Holocene. Location: Europe. Taxon: Atriplex tatarica (Amaranthaceae). Methods: We analysed 780 individuals from 80 populations throughout the current European distribution range, employing chloroplast DNA sequences and microsatellite markers. Results: Five haplotype lineages were recognized based on the results of the cpDNA phylogenetic analyses. These lineages originated 0.43–0.22 myr BP. Bayesian clustering analyses divided populations of A. tatarica into two clusters: (a) populations in the Pannonian Basin and the Bohemian Massif and (b) populations in the North European Plain, the Balkan Peninsula, the Carpathian Arc and the Pontic region. The ABC approach provided the strongest statistical support for a model proposing refugia in the Balkan Peninsula and the Pannonian Basin. Expansions from these refugia occurred around 7,000 yr BP. Main conclusion: Atriplex tatarica represents a continental species growing exclusively in man‐made habitats. It serves as a phylogeographic model for annual ruderal taxa currently spreading in central Europe along highways and representing a large group of alien plant species, the so‐called archaeophytes. Atriplex tatarica survived the last glaciation in both a southerly located Balkan refugium and in a more northerly refugium in the Pannonian Basin. From these, the species has colonized Europe as a result of expansion of humans and the anthropogenic climate change. The massive colonization of central north Europe is very recent, with the expansion estimated to have occurred only hundreds of years ago. [ABSTRACT FROM AUTHOR]

Tremendous interspecific genome size variation is a well known phenomenon, whereas genome size within a species is supposed to be exceptionally stable and thus useful as a taxonomic trait. Using DAPI flow cytometry, we tested the stability of genome size in various representatives of Chenopodium s.s. (Amaranthaceae) across a broad geographical range (from Portugal to eastern Russia) in Eurasia. We sampled 1977 Chenopodium individuals of four different ploidies (di-, tetra-, hexa- and decaploids) from 347 populations. Intraspecific relative genome size variation was low, ranging from 2.0% in C. probstii to 7.7% in C. album, even in the species with broad distributions. We distinguished 12 homogeneous relative genome size groups among the 17 Chenopodium spp. tested. Genome size is useful for distinguishing certain morphologically similar groups of species such as C. suecicum/ C. album, C. vulvaria/ C. pamiricum- C. iljinii/ C. sosnowskyi/ C. karoi. Due to its genome size stability, the cosmopolitan species C. album can be used as an alternative internal standard in flow-cytometric analyses with the additional advantages of annual life cycle, self-compatibility and common occurrence all over the world. Finally, we did not detect any sign of hybridization between Chenopodium spp. of different ploidies. [ABSTRACT FROM AUTHOR]

We reconstructed the historical pattern of postglacial biogeographic range expansion of the boreal tree species Alnus incana in Europe., To assess population genetic structure and diversity, we performed a combined analysis of nuclear microsatellite loci and chloroplast DNA sequences (65 populations, 1004 individuals)., Analysis of haplotype and microsatellite diversity revealed that southeastern refugial populations situated in the Carpathians and the Balkan Peninsula did not spread north and cannot be considered as important source populations for postglacial recolonization of Europe; populations in Eastern Europe did not establish Fennoscandian populations; populations in Fennoscandia and Eastern Europe have no unique genetic cluster, but represent a mix with a predominant cluster typical for Central Europe; and that colonization of Fennoscandia and Eastern Europe took place from Central Europe., Our findings highlight the importance of an effective refugium in Central Europe located outside classical southern refugia confirming the existence of northern refugia for boreal trees in Europe. The postglacial range expansion of A. incana did not follow the model established for Picea abies. Fennoscandian populations are not derived from Eastern European ones, but from Central European ones. [ABSTRACT FROM AUTHOR]

Genetic admixture is supposed to be an important trigger of species expansions because it can create the potential for selection of genotypes suitable for new climatic conditions. Up until now, however, no continent-wide population genetic study has performed a detailed reconstruction of admixture events during natural species expansions. To fill this gap, we analysed the postglacial history of Alnus glutinosa, a keystone species of European swamp habitats, across its entire distribution range using two molecular markers, cp DNA and nuclear microsatellites. Cp DNA revealed multiple southern refugia located in the Iberian, Apennine, Balkan and Anatolian Peninsulas, Corsica and North Africa. Analysis of microsatellites variation revealed three main directions of postglacial expansion: (i) from the northern part of the Iberian Peninsula to Western and Central Europe and subsequently to the British Isles, (ii) from the Apennine Peninsula to the Alps and (iii) from the eastern part of the Balkan Peninsula to the Carpathians followed by expansion towards the Northern European plains. This challenges the classical paradigm that most European populations originated from refugial areas in the Carpathians. It has been shown that colonizing lineages have met several times and formed secondary contact zones with unexpectedly high population genetic diversity in Central Europe and Scandinavia. On the contrary, limited genetic admixture in southern refugial areas of A. glutinosa renders rear-edge populations in the Mediterranean region more vulnerable to extinction due to climate change. [ABSTRACT FROM AUTHOR]

Background/Aims: Recently, new palaeoecological records supported by molecular analyses and palaeodistributional modelling have provided more comprehensive insights into plant behaviour during the last Quaternary cycle. We reviewed the migration history of species of subgenus Alnus during the last 50,000 years in Europe with a focus on (1) a general revision of Alnus history since the Last Glacial Maximum (LGM), (2) evidence of northern refugia of Alnus populations during the LGM and (3) the specific history of Alnus in particular European regions. Methodology: We determined changes in Alnus distribution on the basis of 811 and 68 radiocarbon-dated pollen and macrofossil sites, respectively. We compiled data from the European Pollen Database, the Czech Quaternary Palynological Database, the Eurasian Macrofossil Database and additional literature. Pollen percentage thresholds indicating expansions or retreats were used to describe patterns of past Alnus occurrence. Principal Findings: An expansion of Alnus during the Late Glacial and early Holocene periods supports the presence of alders during the LGM in southern peninsulas and northerly areas in western Europe, the foothills of the Alps, the Carpathians and northeastern Europe. After glaciers withdrew, the ice-free area of Europe was likely colonized from several regional refugia; the deglaciated area of Scandinavia was likely colonized from a single refugium in northeastern Europe. In the more northerly parts of Europe, we found a scale-dependent pattern of Alnus expansion characterised by a synchronous increase of Alnus within individual regions, though with regional differences in the times of the expansion. In southern peninsulas, the Alps and the Carpathians, by contrast, it seems that Alnus expanded differently at individual sites rather than synchronously in whole regions. Conclusions: Our synthesis supports the idea that northern LGM populations were important sources of postglacial Alnus expansion. The delayed Alnus expansion apparent in some regions was likely a result of environmental limitations. [ABSTRACT FROM AUTHOR]

Genome or genomic dominance (GD) is a phenomenon observed in hybrids when one parental genome becomes dominant over the other. It is manifested by the replacement of chromatin of the submissive genome by that of the dominant genome and by biased gene expression. Nucleolar dominance (ND) - the functional expression of only one parental set of ribosomal genes in hybrids - is another example of an intragenomic competitive process which, however, concerns ribosomal DNA only. Although GD and ND are relatively well understood, the nature and extent of their potential interdependence is mostly unknown. Here, we ask whether hybrids showing GD also exhibit ND and, if so, whether the dominant genome is the same. To test this, we used hybrids between Festuca and Lolium grasses (Festulolium), and between two Festuca species in which GD has been observed (with Lolium as the dominant genome in Festulolium and F. pratensis in interspecific Festuca hybrids). Using amplicon sequencing of ITS1 and ITS2 of the 45S ribosomal DNA (rDNA) cluster and molecular cytogenetics, we studied the organization and expression of rDNA in leaf tissue in five hybrid combinations, four generations and 31 genotypes [ F. pratensis × L. multiflorum (F 1 , F 2 , F 3 , BC 1 ), L. multiflorum × F. pratensis (F 1 ), L. multiflorum × F. glaucescens (F 2 ), L. perenne × F. pratensis (F 1 ), F. glaucescens × F. pratensis (F 1 )]. We have found that instant ND occurs in Festulolium, where expression of Lolium -type rDNA reached nearly 100% in all F 1 hybrids and was maintained through subsequent generations. Therefore, ND and GD in Festulolium are manifested by the same dominant genome ( Lolium ). We also confirmed the concordance between GD and ND in an interspecific cross between two Festuca species., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Mahelka, Kopecký, Majka and Krak.)