Mendelian randomization supports bidirectional causality between telomere length and clonal hematopoiesis of indeterminate potential

Human genetic studies support an inverse causal relationship between leukocyte telomere length (LTL) and coronary artery disease (CAD), but directionally mixed effects for LTL and diverse malignancies. Clonal hematopoiesis of indeterminate potential (CHIP), characterized by expansion of hematopoietic cells bearing leukemogenic mutations, predisposes both hematologic malignancy and CAD. TERT (which encodes telomerase reverse transcriptase) is the most significantly associated germline locus for CHIP in genome-wide association studies. Here, we investigated the relationship between CHIP, LTL, and CAD in the Trans-Omics for Precision Medicine (TOPMed) program (n = 63,302) and UK Biobank (n = 47,080). Bidirectional Mendelian randomization studies were consistent with longer genetically imputed LTL increasing propensity to develop CHIP, but CHIP then, in turn, hastens to shorten measured LTL (mLTL). We also demonstrated evidence of modest mediation between CHIP and CAD by mLTL. Our data promote an understanding of potential causal relationships across CHIP and LTL toward prevention of CAD

Genetic determinants of telomere length from 109,122 ancestrally diverse whole-genome sequences in TOPMed

Genetic studies on telomere length are important for understanding age-related diseases. Prior GWASs for leukocyte TL have been limited to European and Asian populations. Here, we report the first sequencing-based association study for TL across ancestrally diverse individuals (European, African, Asian, and Hispanic/Latino) from the NHLBI Trans-Omics for Precision Medicine (TOPMed) program. We used whole-genome sequencing (WGS) of whole blood for variant genotype calling and the bioinformatic estimation of telomere length in n = 109,122 individuals. We identified 59 sentinel variants (p < 5 × 10−9) in 36 loci associated with telomere length, including 20 newly associated loci (13 were replicated in external datasets). There was little evidence of effect size heterogeneity across populations. Fine-mapping at OBFC1 indicated that the independent signals colocalized with cell-type-specific eQTLs for OBFC1 (STN1). Using a multi-variant gene-based approach, we identified two genes newly implicated in telomere length, DCLRE1B (SNM1B) and PARN. In PheWAS, we demonstrated that our TL polygenic trait scores (PTSs) were associated with an increased risk of cancer-related phenotypes

A cladistic analysis of the nomadine bees (Hymenoptera: Apoidea)

This study compares the results of Rozen\u27s cladistic analysis of the larvae of fifteen genera of cleptoparasitic bees in the subfamily Nomadinae with an independent data set of adult characters for the same genera. Adult characters exhibited considerably higher levels of homoplasy and poorer resolution of cladistic relationships, with multiple equally parsimonious cladograms. However, comparison of a Nelson consensus tree based on adult characters with the cladogram based on larval characters reveals three components consistently supported in both analyses (the tribes Epeolini and Ammobatini, and Neopasites + Neolarra), one component supported only by adult characters (lsepeolus + Protepeolus), and one terminal component supported only by larval characters (Nomada + Ammobatini), as well as several more inclusive groupings based on larval characters that are difficult to compare with the adult consensus tree because it shows so much less resolution. When adult and larval characters are combined in a single data matrix, the resulting cladogram closely resembles the cladogram based on larval characters alone, although levels of homoplasy are considerably higher than in the larval analysis