Population variation in trophic niche is widespread among organisms and is of increasing interest given its role in both speciation and adaptation to changing environments. Trinidadian guppies (Poecilia reticulata) inhabiting stream reaches with different predation regimes have rapidly evolved divergent life history traits. Here, we investigated the effects of both predation and resource availability on guppy trophic niches by evaluating their gut contents, resource standing stocks, and δ15N and δ13C stable isotopes across five streams during the wet season. We found that guppies from low predation (LP) sites had a consistently higher trophic position and proportion of invertebrates in their guts and assimilate less epilithon than guppies from high predation (HP) sites. Higher trophic position was also associated with lower benthic invertebrate availability. Our results suggest that LP guppies could be more efficient invertebrate consumers, possibly as an evolutionary response to greater intraspecific competition for higher quality food. This may be intensified by seasonality, as wet season conditions can alter resource availability, feeding rates, and the intensity of intraspecific competition. Understanding how guppy diets vary among communities is critical to elucidating the role of niche shifts in mediating the link between environmental change and the evolution of life histories.

• MeSH
• biologická evoluce MeSH
• dieta * MeSH
• ekosystém * MeSH
• fyziologická adaptace fyziologie   MeSH
• populační dynamika MeSH
• predátorské chování fyziologie   MeSH
• řeky MeSH
• roční období MeSH
• zeměpis MeSH
• živorodka fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• Západoindické souostroví MeSH

BACKGROUND: Downy mildews are the most speciose group of oomycetes and affect crops of great economic importance. So far, there is only a single deeply-sequenced downy mildew genome available, from Hyaloperonospora arabidopsidis. Further genomic resources for downy mildews are required to study their evolution, including pathogenicity effector proteins, such as RxLR effectors. Plasmopara halstedii is a devastating pathogen of sunflower and a potential pathosystem model to study downy mildews, as several Avr-genes and R-genes have been predicted and unlike Arabidopsis downy mildew, large quantities of almost contamination-free material can be obtained easily. RESULTS: Here a high-quality draft genome of Plasmopara halstedii is reported and analysed with respect to various aspects, including genome organisation, secondary metabolism, effector proteins and comparative genomics with other sequenced oomycetes. Interestingly, the present analyses revealed further variation of the RxLR motif, suggesting an important role of the conservation of the dEER-motif. Orthology analyses revealed the conservation of 28 RxLR-like core effectors among Phytophthora species. Only six putative RxLR-like effectors were shared by the two sequenced downy mildews, highlighting the fast and largely independent evolution of two of the three major downy mildew lineages. This is seemingly supported by phylogenomic results, in which downy mildews did not appear to be monophyletic. CONCLUSIONS: The genome resource will be useful for developing markers for monitoring the pathogen population and might provide the basis for new approaches to fight Phytophthora and downy mildew pathogens by targeting core pathogenicity effectors.

• MeSH
• biologická evoluce MeSH
• faktory virulence genetika   MeSH
• fosfolipidy metabolismus   MeSH
• fungální proteiny MeSH
• fylogeneze MeSH
• genom fungální * MeSH
• genomika metody   MeSH
• Helianthus mikrobiologie   MeSH
• heterozygot MeSH
• mikrosatelitní repetice MeSH
• oomycety klasifikace   genetika   metabolismus   MeSH
• Phytophthora genetika   MeSH
• promotorové oblasti (genetika) MeSH
• repetitivní sekvence nukleových kyselin MeSH
• sekundární metabolismus MeSH
• signální transdukce MeSH
• stanovení celkové genové exprese MeSH
• Publikační typ
• časopisecké články MeSH

Understanding the mechanisms driving lineage-specific evolution in both primates and rodents has been hindered by the lack of sister clades with a similar phylogenetic structure having high-quality genome assemblies. Here, we have created chromosome-level assemblies of the Mus caroli and Mus pahari genomes. Together with the Mus musculus and Rattus norvegicus genomes, this set of rodent genomes is similar in divergence times to the Hominidae (human-chimpanzee-gorilla-orangutan). By comparing the evolutionary dynamics between the Muridae and Hominidae, we identified punctate events of chromosome reshuffling that shaped the ancestral karyotype of Mus musculus and Mus caroli between 3 and 6 million yr ago, but that are absent in the Hominidae. Hominidae show between four- and sevenfold lower rates of nucleotide change and feature turnover in both neutral and functional sequences, suggesting an underlying coherence to the Muridae acceleration. Our system of matched, high-quality genome assemblies revealed how specific classes of repeats can play lineage-specific roles in related species. Recent LINE activity has remodeled protein-coding loci to a greater extent across the Muridae than the Hominidae, with functional consequences at the species level such as reproductive isolation. Furthermore, we charted a Muridae-specific retrotransposon expansion at unprecedented resolution, revealing how a single nucleotide mutation transformed a specific SINE element into an active CTCF binding site carrier specifically in Mus caroli, which resulted in thousands of novel, species-specific CTCF binding sites. Our results show that the comparison of matched phylogenetic sets of genomes will be an increasingly powerful strategy for understanding mammalian biology.

• MeSH
• CCCTC-vazebný faktor genetika   MeSH
• chromozomy genetika   MeSH
• dlouhé rozptýlené jaderné elementy genetika   MeSH
• druhová specificita MeSH
• fylogeneze * MeSH
• genom genetika   MeSH
• karyotypizace metody   MeSH
• molekulární evoluce * MeSH
• Muridae genetika   MeSH
• myši MeSH
• retroelementy genetika   MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Výsledky laboratorních studií naznačují, že uživatelky orální hormonální antikoncepce (HA) preferují v porovnání s normálně cyklujícími ženami muže méně maskulinní a podobnější v genech MHC. Řada autorů spekulovala o celospolečensky závažných důsledcích tohoto fenoménu, jako například o vzrůstu rozvodovosti následkem nižší stability dlouhodobých partnerství, která se vytvořila pod vlivem užívání HA. Tyto spekulace však mají v současné době pouze omezenou empirickou podporu. Na základě shrnutí předchozích výzkumů lze pouze říci, že užívání HA ovlivňuje vnímání žen na úrovni partnerských preferencí, kdy je u uživatelek HA pozorováno nižší hodnocení sexuální atraktivity mužů vykazujících znaky genetické kvality a kompatibility k nim než u žen ve folikulární fázi menstruačního cyklu. Zároveň u nich však není ovlivněno hodnocení atraktivity mužů s charakteristikami vhodnými pro vytvoření dlouhodobého partnerství. Do současnosti neexistovaly studie, které by testovaly, zda se dlouhodobá partnerství vytvořená pod vlivem HA skutečně častěji rozpadají či zda jsou partneři v nich podobnější v genech MHC. Nejnovější výzkumy realizované mimo kontext laboratoře naznačují, že by výběr partnerů s vyššími partnerskými kvalitami spolu s výskytem propartnersky orientovaných behaviorálních projevů u zadaných uživatelek HA (např. nižší výskyt nevěry, vyšší frekvence dyadických sexuálních aktivit) mohly v reálném prostředí převážit negativa výběru partnera méně geneticky kvalitního a kompatibilního.

In laboratory conditions, the use of oral contraceptives (OC) has been shown to disrupt mate preferences (e.g. for masculinity and genetic dissimilarity) that are considered to be adaptive in naturally cycling women. The consequence of OC influenced mate choice on relationship satisfaction and durability in an ecological context has been extensively debated. However, there is only limited empirical support for these speculations. The stability of long-term couples, who met under the influence of OC use, has not been studied in an ecological context. We can only assume that OC use influences cognitive aspects of attractiveness ratings. OC users were found to give lower value to such sexual attractiveness of male stimuli which was associated with genetic quality and compatibility in comparison with normally cycling women in their follicular phase. However, the evaluation of male stimuli with the cues of higher parental and relationship qualities did not differ from ratings of normally cycling women. Results of recent studies accomplished outside the laboratory context suggest, that the bias in mate choice towards the preferences of men with higher long-term relationship qualities in conjunction with higher frequency of mate-retention behaviour observed in OC users (e.g. higher frequency of dyadic sexual activities, suppressed infidelity tendencies) can override the negatives of OC influenced mate preferences.

• Klíčová slova
• evoluční psychologie, partnerský výběr,
• MeSH
• antikoncepční chování psychologie   trendy   MeSH
• biologická evoluce MeSH
• financování organizované MeSH
• kontraceptiva orální hormonální farmakologie   terapeutické užití   MeSH
• lidé MeSH
• menstruace fyziologie   psychologie   účinky léků   MeSH
• menstruační cyklus MeSH
• metaanalýza jako téma MeSH
• psychologie metody   MeSH
• sexualita fyziologie   psychologie   účinky léků   MeSH
• sexuální partneři psychologie   MeSH
• statistika jako téma MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• přehledy MeSH

Sex chromosomes are generally derived from a pair of classical type-A chromosomes, and relatively few alternative models have been proposed up to now.1,2 B chromosomes (Bs) are supernumerary and dispensable chromosomes with non-Mendelian inheritance found in many plant and animal species3,4 that have often been considered as selfish genetic elements that behave as genome parasites.5,6 The observation that in some species Bs can be either restricted or predominant in one sex7-14 raised the interesting hypothesis that Bs could play a role in sex determination.15 The characterization of putative B master sex-determining (MSD) genes, however, has not yet been provided to support this hypothesis. Here, in Astyanax mexicanus cavefish originating from Pachón cave, we show that Bs are strongly male predominant. Based on a high-quality genome assembly of a B-carrying male, we characterized the Pachón cavefish B sequence and found that it contains two duplicated loci of the putative MSD gene growth differentiation factor 6b (gdf6b). Supporting its role as an MSD gene, we found that the Pachón cavefish gdf6b gene is expressed specifically in differentiating male gonads, and that its knockout induces male-to-female sex reversal in B-carrying males. This demonstrates that gdf6b is necessary for triggering male sex determination in Pachón cavefish. Altogether these results bring multiple and independent lines of evidence supporting the conclusion that the Pachón cavefish B is a "B-sex" chromosome that contains duplicated copies of the gdf6b gene, which can promote male sex determination in this species.

• MeSH
• biologická evoluce MeSH
• Characidae * genetika   MeSH
• jeskyně MeSH
• pohlavní chromozomy genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Sustainable food production in the context of climate change necessitates diversification of agriculture and a more efficient utilization of plant genetic resources. Fonio millet (Digitaria exilis) is an orphan African cereal crop with a great potential for dryland agriculture. Here, we establish high-quality genomic resources to facilitate fonio improvement through molecular breeding. These include a chromosome-scale reference assembly and deep re-sequencing of 183 cultivated and wild Digitaria accessions, enabling insights into genetic diversity, population structure, and domestication. Fonio diversity is shaped by climatic, geographic, and ethnolinguistic factors. Two genes associated with seed size and shattering showed signatures of selection. Most known domestication genes from other cereal models however have not experienced strong selection in fonio, providing direct targets to rapidly improve this crop for agriculture in hot and dry environments.

• MeSH
• anotace sekvence MeSH
• Digitaria klasifikace   genetika   MeSH
• domestikace MeSH
• druhová specificita MeSH
• genetická variace MeSH
• genom rostlinný MeSH
• jedlá semena klasifikace   genetika   MeSH
• klimatické změny MeSH
• molekulární evoluce MeSH
• selekce (genetika) MeSH
• zemědělství metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Afrika MeSH

Plant and microbial community composition in connection with soil chemistry determines soil nutrient cycling. The study aimed at demonstrating links between plant and microbial communities and soil chemistry occurring among and within four sites: two pine forests with contrasting soil pH and two grasslands of dissimilar soil chemistry and vegetation. Soil was characterized by C and N content, particle size, and profiles of low-molecular-weight compounds determined by high-performance liquid chromatography (HPLC) of soil extracts. Bacterial and actinobacterial community composition was assessed by terminal restriction fragment length polymorphism (T-RFLP) and cloning followed by sequencing. Abundances of bacteria, fungi, and actinobacteria were determined by quantitative PCR. In addition, a pool of secondary metabolites was estimated by erm resistance genes coding for rRNA methyltransferases. The sites were characterized by a stable proportion of C/N within each site, while on a larger scale, the grasslands had a significantly lower C/N ratio than the forests. A Spearman's test showed that soil pH was correlated with bacterial community composition not only among sites but also within each site. Bacterial, actinobacterial, and fungal abundances were related to carbon sources while T-RFLP-assessed microbial community composition was correlated with the chemical environment represented by HPLC profiles. Actinobacteria community composition was the only studied microbial characteristic correlated to all measured factors. It was concluded that the microbial communities of our sites were influenced primarily not only by soil abiotic characteristics but also by dominant litter quality, particularly, by percentage of recalcitrant compounds.

• MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   MeSH
• bakteriální nálož MeSH
• biodiverzita MeSH
• DNA bakterií chemie   genetika   MeSH
• dusík analýza   MeSH
• fylogeneze MeSH
• houby klasifikace   genetika   izolace a purifikace   MeSH
• koncentrace vodíkových iontů MeSH
• methyltransferasy genetika   MeSH
• molekulární sekvence - údaje MeSH
• organické látky analýza   MeSH
• počet mikrobiálních kolonií MeSH
• polymorfismus délky restrikčních fragmentů MeSH
• půda chemie   MeSH
• půdní mikrobiologie MeSH
• rostliny mikrobiologie   MeSH
• sekvenční analýza DNA MeSH
• shluková analýza MeSH
• uhlík analýza   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH