17 research outputs found
The choice of tree prior and molecular clock does not substantially affect phylogenetic inferences of diversification rates
Comparative methods allow researchers to make inferences about evolutionary processes and patterns from phylogenetic trees. In Bayesian phylogenetics, estimating a phylogeny requires specifying priors on parameters characterizing the branching process and rates of substitution among lineages, in addition to others. Accordingly, characterizing the effect of prior selection on phylogenies is an active area of research. The choice of priors may systematically bias phylogenetic reconstruction and, subsequently, affect conclusions drawn from the resulting phylogeny. Here, we focus on the impact of priors in Bayesian phylogenetic inference and evaluate how they affect the estimation of parameters in macroevolutionary models of lineage diversification. Specifically, we simulate trees under combinations of tree priors and molecular clocks, simulate sequence data, estimate trees, and estimate diversification parameters (e.g., speciation and extinction rates) from these trees. When substitution rate heterogeneity is large, diversification rate estimates deviate substantially from those estimated under the simulation conditions when not captured by an appropriate choice of relaxed molecular clock. However, in general, we find that the choice of tree prior and molecular clock has relatively little impact on the estimation of diversification rates insofar as the sequence data are sufficiently informative and substitution rate heterogeneity among lineages is low-to-moderate
Phylogenetic niche conservatism - common pitfalls and ways forward
International audienc
Detecting the macroevolutionary signal of species interactions
Species interactions lie at the heart of many theories of macroevolution, from adaptive radiation to the Red Queen. Although some theories describe the imprint that interactions will have over long time scales, we are still missing a comprehensive understanding of the effects of interactions on macroevolution. Current research shows strong evidence for the impact of interactions on macroevolutionary patterns of trait evolution and diversification, yet many macroevolutionary studies have only a tenuous relationship to ecological studies of interactions over shorter time scales. We review current research in this area, highlighting approaches that explicitly model species interactions and connect them to broad‐scale macroevolutionary patterns. We also suggest that progress has been made by taking an integrative interdisciplinary look at individual clades. We focus on African cichlids as a case study of how this approach can be fruitful. Overall, while the evidence for species interactions shaping macroevolution is strong, further work using integrative and model‐based approaches is needed to spur progress towards understanding the complex dynamics that structure communities over time and space
Functional distinctiveness of major plant lineages
Plant traits vary widely across species and underpin differences in ecological strategy. Despite centuries of interest, the contributions of different evolutionary lineages to modern-day functional diversity remain poorly quantified. Expanding data bases of plant traits plus rapidly improving phylogenies enable for the first time a data-driven global picture of plant functional diversity across the major clades of higher plants. We mapped five key traits relevant to metabolism, resource competition and reproductive strategy onto a phylogeny across 48324 vascular plant species world-wide, along with climate and biogeographic data. Using a novel metric, we test whether major plant lineages are functionally distinctive. We then highlight the trait-lineage combinations that are most functionally distinctive within the present-day spread of ecological strategies. For some trait-clade combinations, knowing the clade of a species conveys little information to neo- and palaeo-ecologists. In other trait-clade combinations, the clade identity can be highly revealing, especially informative clade-trait combinations include Proteaceae, which is highly distinctive, representing the global slow extreme of the leaf economic spectrum. Magnoliidae and Rosidae contribute large leaf sizes and seed masses and have distinctively warm, wet climatic distributions. Synthesis. This analysis provides a shortlist of the most distinctive trait-lineage combinations along with their geographic and climatic context: a global view of extant functional diversity across the tips of the vascular plant phylogeny. This analysis provides a shortlist of the most distinctive trait-lineage combinations along with their geographic and climatic context: a global view of extant functional diversity across the tips of the vascular plant phylogeny. © 2014 British Ecological Society
International genome-wide association study consortium identifies novel loci associated with blood pressure in children and adolescents.
BACKGROUND: -Our aim was to identify genetic variants associated with blood pressure (BP) in childhood and adolescence. METHODS AND RESULTS: -Genome-wide association study data from participating European ancestry cohorts of the EAGLE ( EA: rly G: enetics and L: ifecourse E: pidemiology) Consortium was meta-analysed across three 'epochs'; pre-puberty [4-7 years], puberty [8-12 years] and post-puberty [13-20 years]. Two novel loci were identified as having genome-wide associations with systolic blood pressure across specific age epochs; rs1563894 (ITGA11, located in active H3K27Ac mark and transcription factor CHiP and CpG methylation site) during pre-puberty (p = 2.86 × 10(-8)) and rs872256 during puberty (p = 8.67 × 10(-9)). Several SNP 'clusters' were also associated with childhood BP at p < 5 × 10(-3). Using a p-value threshold of < 5 × 10(-3) we found some overlap in variants across the different age epochs within our study, and between several SNPs in any of the three epochs and adult BP related SNPs. CONCLUSIONS: -Our results suggest that genetic determinants of blood pressure act from childhood, develop over the lifecourse, and show some evidence of age-specific effects
From passive to active consumers? Later life consumption in the UK from 1968-2005
The significance of the UK's ageing population has been generally acknowledged, however its implications for consumption have been neglected. The consumption patterns of older people are important given that the end of the 20th century witnessed profound changes to the nature of later life, many linked to the emergence of ‘consumer societies’ in the UK and elsewhere. The uneven nature of retirement, as well as the relative affluence of many retired people, has important effects on patterns and experiences of consumption. This paper charts consumption by retired households in two areas; ownership of key consumer goods and key components of household spending. We investigate how these expenditure trends compare with other household types and across pseudo-birth cohorts. We draw data from 9 years of the Family Expenditure Survey taken at 5 year intervals between 1968 and 2004/5. The data demonstrate the growing extent of ownership of key goods in retired households but also show the differences in proportional expenditure between retired households and the employed. We also note differences between pseudo-birth cohorts and conclude that consumption patterns in later life are influenced by the generational habitus of the differing cohorts who entered retirement between the 1960s and the present day
Hypothesis-driven genome-wide association studies provide novel insights into genetics of reading disabilities.
Reading Disability (RD) is often characterized by difficulties in the phonology of the language. While the molecular mechanisms underlying it are largely undetermined, loci are being revealed by genome-wide association studies (GWAS). In a previous GWAS for word reading (Price, 2020), we observed that top single-nucleotide polymorphisms (SNPs) were located near to or in genes involved in neuronal migration/axon guidance (NM/AG) or loci implicated in autism spectrum disorder (ASD). A prominent theory of RD etiology posits that it involves disturbed neuronal migration, while potential links between RD-ASD have not been extensively investigated. To improve power to identify associated loci, we up-weighted variants involved in NM/AG or ASD, separately, and performed a new Hypothesis-Driven (HD)–GWAS. The approach was applied to a Toronto RD sample and a meta-analysis of the GenLang Consortium. For the Toronto sample (n = 624), no SNPs reached significance; however, by gene-set analysis, the joint contribution of ASD-related genes passed the threshold (p~1.45 × 10–2, threshold = 2.5 × 10–2). For the GenLang Cohort (n = 26,558), SNPs in DOCK7 and CDH4 showed significant association for the NM/AG hypothesis (sFDR q = 1.02 × 10–2). To make the GenLang dataset more similar to Toronto, we repeated the analysis restricting to samples selected for reading/language deficits (n = 4152). In this GenLang selected subset, we found significant association for a locus intergenic between BTG3-C21orf91 for both hypotheses (sFDR q < 9.00 × 10–4). This study contributes candidate loci to the genetics of word reading. Data also suggest that, although different variants may be involved, alleles implicated in ASD risk may be found in the same genes as those implicated in word reading. This finding is limited to the Toronto sample suggesting that ascertainment influences genetic associations
Genome-wide analyses of individual differences in quantitatively assessed reading- and language-related skills in up to 34,000 people.
The use of spoken and written language is a fundamental human capacity. Individual differences in reading- and language-related skills are influenced by genetic variation, with twin-based heritability estimates of 30 to 80% depending on the trait. The genetic architecture is complex, heterogeneous, and multifactorial, but investigations of contributions of single-nucleotide polymorphisms (SNPs) were thus far underpowered. We present a multicohort genome-wide association study (GWAS) of five traits assessed individually using psychometric measures (word reading, nonword reading, spelling, phoneme awareness, and nonword repetition) in samples of 13,633 to 33,959 participants aged 5 to 26 y. We identified genome-wide significant association with word reading (rs11208009, P = 1.098 × 10-8) at a locus that has not been associated with intelligence or educational attainment. All five reading-/language-related traits showed robust SNP heritability, accounting for 13 to 26% of trait variability. Genomic structural equation modeling revealed a shared genetic factor explaining most of the variation in word/nonword reading, spelling, and phoneme awareness, which only partially overlapped with genetic variation contributing to nonword repetition, intelligence, and educational attainment. A multivariate GWAS of word/nonword reading, spelling, and phoneme awareness maximized power for follow-up investigation. Genetic correlation analysis with neuroimaging traits identified an association with the surface area of the banks of the left superior temporal sulcus, a brain region linked to the processing of spoken and written language. Heritability was enriched for genomic elements regulating gene expression in the fetal brain and in chromosomal regions that are depleted of Neanderthal variants. Together, these results provide avenues for deciphering the biological underpinnings of uniquely human traits