Showing papers by "Southern Illinois University Carbondale published in 2004"
TL;DR: In this article, the authors examined the links between senescence and aging in vivo, and showed that expression of p16INK4a and Arf markedly increases in almost all rodent tissues with advancing age, while there is little or no change in the expression of related cell cycle inhibitors.
Abstract: The Ink4a/Arf locus encodes 2 tumor suppressor molecules, p16INK4a and Arf, which are principal mediators of cellular senescence. To study the links between senescence and aging in vivo, we examined Ink4a/Arf expression in rodent models of aging. We show that expression of p16INK4a and Arf markedly increases in almost all rodent tissues with advancing age, while there is little or no change in the expression of other related cell cycle inhibitors. The increase in expression is restricted to well-defined compartments within each organ studied and occurs in both epithelial and stromal cells of diverse lineages. The age-associated increase in expression of p16INK4a and Arf is attenuated in the kidney, ovary, and heart by caloric restriction, and this decrease correlates with diminished expression of an in vivo marker of senescence, as well as decreased pathology of those organs. Last, the age-related increase in Ink4a/Arf expression can be independently attributed to the expression of Ets-1, a known p16INK4a transcriptional activator, as well as unknown Ink4a/Arf coregulatory molecules. These data suggest that expression of the Ink4a/Arf tumor suppressor locus is a robust biomarker, and possible effector, of mammalian aging.
1,369 citations
TL;DR: A research model was proposed that suggested three factors that have been found to be influential in previous research in the perception of strategic value of other information technologies: operational support, managerial productivity, and strategic decision aids that influence electronic commerce adoption.
1,080 citations
Vanderbilt University1, University of Southern California2, University of Texas MD Anderson Cancer Center3, University of Wisconsin-Madison4, University of California, Los Angeles5, National Center for Genome Resources6, Portland VA Medical Center7, University of Colorado Boulder8, University of Pennsylvania9, Hannover Medical School10, Johns Hopkins University11, Oregon Health & Science University12, Cornell University13, University of Michigan14, University of Tennessee Health Science Center15, Washington University in St. Louis16, University of Toronto17, University of Memphis18, Medical Research Council19, University of Massachusetts Medical School20, Hebrew University of Jerusalem21, Université de Montréal22, Purdue University23, University of California, Davis24, Academy of Sciences of the Czech Republic25, University at Buffalo26, Emory University27, University of Cincinnati28, University of Texas Southwestern Medical Center29, New York University30, University of Groningen31, Rutgers University32, Stanford University33, Max Planck Society34, National Institutes of Health35, University of Alabama at Birmingham36, International Livestock Research Institute37, Heidelberg University38, Medical College of Wisconsin39, Icahn School of Medicine at Mount Sinai40, Oak Ridge National Laboratory41, Charité42, University of Antwerp43, RWTH Aachen University44, Paul Sabatier University45, University of California, San Francisco46, McGill University47, Pasteur Institute48, University of Western Australia49, Yale University50, University of Oxford51, Case Western Reserve University52, Roswell Park Cancer Institute53, University of Kentucky54, University of Helsinki55, University of Nebraska–Lincoln56, Harvard University57, Merck & Co.58, King's College London59, Northwestern University60, Shriners Hospitals for Children61, Thomas Jefferson University62, Novartis63, University of North Carolina at Chapel Hill64, Southern Illinois University Carbondale65, University of Rochester66
TL;DR: The Collaborative Cross will provide a common reference panel specifically designed for the integrative analysis of complex systems and will change the way the authors approach human health and disease.
Abstract: The goal of the Complex Trait Consortium is to promote the development of resources that can be used to understand, treat and ultimately prevent pervasive human diseases. Existing and proposed mouse resources that are optimized to study the actions of isolated genetic loci on a fixed background are less effective for studying intact polygenic networks and interactions among genes, environments, pathogens and other factors. The Collaborative Cross will provide a common reference panel specifically designed for the integrative analysis of complex systems and will change the way we approach human health and disease.
1,040 citations
TL;DR: In this article, a general formulation and a solution scheme for a class of Fractional Optimal Control Problems (FOCPs) for those systems are presented, where the performance index of a FOCP is considered as a function of both the state and the control variables, and the dynamic constraints are expressed by a set of FDEs.
Abstract: Accurate modeling of many dynamic systems leads to a set of Fractional Differential Equations (FDEs). This paper presents a general formulation and a solution scheme for a class of Fractional Optimal Control Problems (FOCPs) for those systems. The fractional derivative is described in the Riemann–Liouville sense. The performance index of a FOCP is considered as a function of both the state and the control variables, and the dynamic constraints are expressed by a set of FDEs. The Calculus of Variations, the Lagrange multiplier, and the formula for fractional integration by parts are used to obtain Euler–Lagrange equations for the FOCP. The formulation presented and the resulting equations are very similar to those that appear in the classical optimal control theory. Thus, the present formulation essentially extends the classical control theory to fractional dynamic system. The formulation is used to derive the control equations for a quadratic linear fractional control problem. An approach similar to a variational virtual work coupled with the Lagrange multiplier technique is presented to find the approximate numerical solution of the resulting equations. Numerical solutions for two fractional systems, a time-invariant and a time-varying, are presented to demonstrate the feasibility of the method. It is shown that (1) the solutions converge as the number of approximating terms increase, and (2) the solutions approach to classical solutions as the order of the fractional derivatives approach to 1. The formulation presented is simple and can be extended to other FOCPs. It is hoped that the simplicity of this formulation will initiate a new interest in the area of optimal control of fractional systems.
661 citations
TL;DR: Preschool children were administered an executive function battery that was reduced empirically to working memory, inhibitory control, and shifting abilities and predicted early arithmetic competency, with the observed relations robust after controlling statistically for child age, maternal education, and child vocabulary.
Abstract: Mathematical ability is related to both activation of the prefrontal cortex in neuroimaging studies of adults and to executive functions in school-age children. The purpose of this study was to determine whether executive functions were related to emergent mathematical proficiency in preschool children. Preschool children (N = 96) were administered an executive function battery that was reduced empirically to working memory (WM), inhibitory control (IC), and shifting abilities by calculating composite scores derived from principal component analysis. Both WM and IC predicted early arithmetic competency, with the observed relations robust after controlling statistically for child age, maternal education, and child vocabulary. Only IC accounted for unique variance in mathematical skills, after the contribution of other executive functions were controlled statistically as well. Specific executive functions are related to emergent mathematical proficiency in this age range. Longitudinal studies using structural equation modeling are necessary to better characterize these ontogenetic relations.
623 citations
TL;DR: The recent completion of the whole-genome sequence of the perchlorate-reducing microorganism Dechloromonas aromatica offers further insight into the evolution and regulation of this unique metabolic pathway.
Abstract: It is less than 7 years since perchlorate, a predominantly man-made toxic anion, was first identified as a significant water contaminant throughout the United States. Owing to its solubility and non-reactivity, bioremediation was targeted as the most promising solution for the problem of perchlorate contamination. Since 1996, concerted efforts have resulted in significant advances in our understanding of the microbiology, biochemistry and genetics of the microorganisms that are capable of reductively transforming perchlorate into innocuous chloride. The recent completion of the whole-genome sequence of the perchlorate-reducing microorganism Dechloromonas aromatica offers further insight into the evolution and regulation of this unique metabolic pathway. Several in situ and ex situ bioremediative processes have been engineered, and many monitoring tools that are based on immunology, molecular biology and stable isotope content are now available. As such, the rapid scientific response to this emerging contaminant offers great hope for its successful elimination from contaminated environments in the future.
504 citations
TL;DR: In this article, the authors developed an instrument to measure the festival and special event organizers' perceptions of the impacts of festivals and special events on local communities based on the literature and the suggestions of experts in the area.
493 citations
TL;DR: This article developed a theory of opinion updating where citizens who deliberate revise their prior beliefs, particularly when they encounter consensual messages, and found that opinion strength moderates the deliberative opinion change process.
Abstract: Theorists argue that deliberation promotes enlightenment and consensus, but scholars do not know how deliberation affects policy opinions. Using the deliberative democracy and public opinion literatures as a guide, I develop a theory of opinion updating where citizens who deliberate revise their prior beliefs, particularly when they encounter consensual messages. A key aspect of this model is that opinion strength moderates the deliberative opinion change process. In two separate propensity score analyses using panel survey data from a deliberative forum and cross-sectional surveys, I show how deliberation and discussion both affect opinions toward Social Security reform. However, deliberation differs from ordinary discussion in that participants soften strongly held views, encounter different perspectives, and learn readily. Thus, deliberation increases knowledge and alters opinions, but it does so selectively based on the quality and diversity of the messages as well as the willingness of participants to keep an open mind.
412 citations
TL;DR: In this paper, the authors reveal the motivations for agri-tourism entrepreneurship among Virginia farm families and explore Weber's theory of formal and substantive rationality as a possible theoretical framework for agritourism entrepreneurs.
Abstract: The purpose of this study was to reveal the motivations for agri-tourism entrepreneurship among Virginia farm families and to explore Weber’s theory of formal and substantive rationality as a possible theoretical framework for agritourism entrepreneurship motivation. Results of this study support the use of Weber’s theory of formal and substantive rationality as a framework for the dynamic nature of motivations for agri-tourism entrepreneurship between formal (primarily economic) reasons and substantive (primarily socio-cultural) reasons. Respondents indicated that Virginia farm families owned small farms, utilized farming as a secondary income source, and indicated their most popular agritourism activities to be pick-your-own produce, Christmas tree sales, hayrides, children’s educational programs, petting zoos, and on-farm festivals. Agri-tourism planners should be aware that acres owned, economic dependence on farming operation, and perceived popularity of agri-tourism activities are influential factor...
405 citations
TL;DR: This study provides one of the first geographically broad assessments of pyrethroids in areas highly affected by agriculture and suggests there is a greater need to examine sediment-associated pesticide residues and their potential for uptake by and toxicity to benthic organisms.
Abstract: The agricultural industry and urban pesticide users are increasingly relying upon pyrethroid insecticides and shifting to more potent members of the class, yet little information is available on residues of these substances in aquatic systems under conditions of actual use. Seventy sediment samples were collected over a 10-county area in the agriculture-dominated Central Valley of California, with most sites located in irrigation canals and small creeks dominated by agricultural effluent. The sediments were analyzed for 26 pesticides including five pyrethroids, 20 organochlorines, and one organophosphate. Ten-day sediment toxicity tests were conducted using the amphipod Hyalella azteca and, for some samples, the midge Chironomus tentans. Forty-two percent of the locations sampled caused significant mortality to one test species on at least one occasion. Fourteen percent of the sites (two creeks and four irrigation canals) showed extreme toxicity (>80% mortality) on at least one occasion. Pyrethroid pestic...
301 citations
TL;DR: The common use of strategies that may not promote healthful weight suggests work is needed to develop culturally and socioeconomically effective overweight prevention programs.
Abstract: Parents play an important role in the development of their children's eating behaviors. We conducted 12 focus groups (three white, three African-American, and three Hispanic-American low-income groups; three white middle-income groups) of mothers (N=101) of 2- to less than 5-year-old children to explore maternal attitudes, concerns, and practices related to child feeding and perceptions about child weight. We identified the following major themes from responses to our standardized focus group guide: 12 groups wanted to provide good nutrition, and most wanted children to avoid eating too many sweets and processed foods; 12 groups prepared foods their children liked, accommodated specific requests, and used bribes and rewards to accomplish their feeding goals (sweets were commonly used as bribes, rewards, or pacifiers); and 11 of 12 groups believed their children were prevaricating when they said they were full and mothers encouraged them to eat more. The common use of strategies that may not promote healthful weight suggests work is needed to develop culturally and socioeconomically effective overweight prevention programs. Further study is needed to verify racial/ethnic or income differences in attitudes, practices, and concerns about child feeding and perceptions of child weight.
TL;DR: Significant advances have been reported in the use of plants for the phytoremediation of cyanide compounds and evidence for the biodegradation of thiocyanate and metal-cyanide complexes has become available, however, physical and economic factors still limit the application of cyanides biodegrades.
TL;DR: In this article, the authors use intraday data to examine whether traders herd during periods of extreme market movements using sector Exchange Traded Funds (ETFs) using two procedures, one based on identifying extreme up market and down market periods and the other based on incorporating a nonlinear term in a regression specification, are used to identify the possibility of the existence of herding behavior in nine sector ETFs traded on the American Stock Exchange.
TL;DR: The QTL found in this study may assist breeders in marker-assisted selection (MAS) to retain current positive QTL in modern soybeans while simultaneously pyramiding additional QTL from new germplasm.
Abstract: Soybean [Glycine max (L.) Merr.] is a versatile crop due to its multitude of uses as a high protein meal and vegetable oil. Soybean seed traits such as seed protein and oil concentration and seed size are important quantitative traits. The objective of this study was to identify representative protein, oil, and seed size quantitative trait loci (QTL) in soybean. A recombinant inbred line (RIL) population consisting of 131 F6-derived lines was created from two prominent ancestors of North American soybeans (‘Essex’ and ‘Williams’) and the RILs were grown in six environments. One hundred simple sequence repeat (SSR) markers spaced throughout the genome were mapped in this population. There were a total of four protein, six oil, and seven seed size QTL found in this population. The QTL found in this study may assist breeders in marker-assisted selection (MAS) to retain current positive QTL in modern soybeans while simultaneously pyramiding additional QTL from new germplasm.
TL;DR: In this article, the authors examined 136 voluntary appointment announcements over 1990-2001 and found significantly positive stock price reaction when new members of audit committees had financial expertise, indicating that market rewards firms that appoint financial experts to their audit committees.
TL;DR: In this paper, a density functional theory with a plane wave basis set was used to study the stability of planar and layered platinum clusters, and the results showed that planar platinum clusters of up to nine atoms are as stable as their three-dimensional isomers.
Abstract: Platinum clusters of up to 55 atoms were studied using density functional theory with a plane wave basis set. The results show that planar platinum clusters of up to nine atoms are as stable as their three-dimensional isomers and the six-atom planar cluster is, surprisingly, more stable than its three-dimensional isomers. Among the three-dimensional platinum clusters investigated in this work, the layered clusters are found to be as stable as their spherical close-packed isomers. The high stability of planar and layered clusters suggests that it is easy to grow a platinum monolayer or multilayer. The existence of many energetically possible isomers shows a fluxional structural characteristic of platinum clusters. The effect of the spin−orbit coupling was investigated, and the results show that the relative stability of the Pt clusters is not affected although the binding energy of the cluster increases if the spin−orbit coupling is included in the calculation. Most of the platinum clusters studied here sh...
TL;DR: 7-DHC can form 7-DHP through P450scc side-chain cleavage, which may serve as a substrate for further conversions into hydroxy derivatives through existing steroidogenic enzymes, and has the potential to generate a variety of molecules depending on local steroidogenic activity and access to UVB.
Abstract: Following up on our previous findings that the skin possesses steroidogenic activity from progesterone, we now show widespread cutaneous expression of the full cytochrome P450 side-chain cleavage (P450scc) system required for the intracellular catalytic production of pregnenolone, i.e. the genes and proteins for P450scc enzyme, adrenodoxin, adrenodoxin reductase and MLN64. Functionality of the system was confirmed in mitochondria from skin cells. Moreover, purified mammalian P450scc enzyme and, most importantly, mitochondria isolated from placenta and adrenals produced robust transformation of 7-dehydrocholesterol (7-DHC; precursor to cholesterol and vitamin D3) to 7-dehydropregnenolone (7-DHP). Product identity was confirmed by comparison with the chemically synthesized standard and chromatographic, MS and NMR analyses. Reaction kinetics for the conversion of 7-DHC into 7-DHP were similar to those for cholesterol conversion into pregnenolone. Thus, 7-DHC can form 7-DHP through P450scc side-chain cleavage, which may serve as a substrate for further conversions into hydroxy derivatives through existing steroidogenic enzymes. In the skin, 5,7-steroidal dienes (7-DHP and its hydroxy derivatives), whether synthesized locally or delivered by the circulation, may undergo UVB-induced intramolecular rearrangements to vitamin D3-like derivatives. This novel pathway has the potential to generate a variety of molecules depending on local steroidogenic activity and access to UVB.
TL;DR: In this paper, the authors show that earnings management may exacerbate agency problems and hypothesize that earnings-increasing earnings management occurs more frequently following duality-creating successions than otherwise.
Abstract: We relate impression and earnings management to the field of ethnostatistics, the study of how statistics are produced and managed. By further linking impression management and agency theory, we show that earnings management may exacerbate agency problems. We hypothesize that earnings-increasing earnings management occurs more frequently following duality-creating successions than otherwise. A dual CEO/Chair would have greater authority to control the impression the company wants to make with its financial reports and may also be operating with greater expectations to produce positive results. Using a sample of 173 duality-creating succession announcements and 112 non-duality creating succession announcements, we find empirical results consistent with this hypothesis.
TL;DR: The data analyses suggested that collaborative conflict management style positively impacted satisfaction with the decision making process, perceived decision quality, and perceived participation of the virtual teams.
TL;DR: In this article, the cointegration analysis suggests that the pure oil industry equity system and the mixed oil price/equity index system offers more opportunities for long-run portfolio diversification and less market integration than the pure-oil price systems.
TL;DR: Members of the ALDH gene superfamily in Arabidopsis are identified and a revised, unified nomenclature for these ALDH genes is provided, which describes the role of ALDHs in cytoplasmic male sterility, plant defense and abiotic stress tolerance.
TL;DR: Complementation analysis by stable potato transformation showed that the gene Gro1-4 conferred resistance to G. rostochiensis pathotype Ro1, and RT-PCR demonstrated that members of the Gro1 gene family are expressed in most potato tissues.
Abstract: The endoparasitic root cyst nematode Globodera rostochiensis causes considerable damage in potato cultivation. In the past, major genes for nematode resistance have been introgressed from related potato species into cultivars. Elucidating the molecular basis of resistance will contribute to the understanding of nematode-plant interactions and assist in breeding nematode-resistant cultivars. The Gro1 resistance locus to G. rostochiensis on potato chromosome VII co-localized with a resistance-gene-like (RGL) DNA marker. This marker was used to isolate from genomic libraries 15 members of a closely related candidate gene family. Analysis of inheritance, linkage mapping, and sequencing reduced the number of candidate genes to three. Complementation analysis by stable potato transformation showed that the gene Gro1-4 conferred resistance to G. rostochiensis pathotype Ro1. Gro1-4 encodes a protein of 1136 amino acids that contains Toll-interleukin 1 receptor (TIR), nucleotide-binding (NB), leucine-rich repeat (LRR) homology domains and a C-terminal domain with unknown function. The deduced Gro1-4 protein differed by 29 amino acid changes from susceptible members of the Gro1 gene family. Sequence characterization of 13 members of the Gro1 gene family revealed putative regulatory elements and a variable microsatellite in the promoter region, insertion of a retrotransposon-like element in the first intron, and a stop codon in the NB coding region of some genes. Sequence analysis of RT-PCR products showed that Gro1-4 is expressed, among other members of the family including putative pseudogenes, in non-infected roots of nematode-resistant plants. RT-PCR also demonstrated that members of the Gro1 gene family are expressed in most potato tissues.
TL;DR: In this paper, the authors introduce the field of mixture toxicity and the challenges in regulating pesticide mixtures, and present several challenges to adequately protect the environment from mixture toxicity; these challenges include understanding the interactions of toxicants within an organism, identifying the mixtures that most commonly occur and cause adverse effects, and developing a regulatory structure capable of minimizing environmental impacts.
Abstract: This paper introduces the field of mixture toxicity and the challenges in regulating pesticide mixtures. Even though pesticides are unique chemical stressors designed to have biological activity that can affect a number of nontarget species, they are intentionally placed into the environment in large quantities. Currently, methods and terminology for evaluating mixture toxicity are poorly established. The most common approach used is the assumption of additive concentration, with the concentrations adjusted for potency to a reference toxicant. Using this approach, the joint action of pesticides that have similar chemical structures and modes of toxic action can be predicted. However, this approach and other modeling techniques often provide little insight into the observed toxicity produced by mixtures of pesticides from different classes. Particularly difficult to model are mixtures that involve a secondary toxicant that changes the toxicokinetics of a primary toxicant. This may result in increased activation or a change in the persistence of the primary toxicant within the organism and may be responsible for a several-fold increase or decrease in toxicity. At present, the ecological effects caused by mixtures of pesticides are given little consideration in the regulatory process. However, mixtures are being considered in relation to human health in the pesticide registration process, setting a precedent that could be followed for ecological protection. Additionally, pesticide mixtures may be regulated through toxicity testing of surface water under the Clean Water Act. The limits of our basic knowledge of how mixtures interact are compromising both these avenues for regulating mixtures. We face many challenges to adequately protecting the environment from mixture toxicity; these challenges include understanding the interactions of toxicants within an organism, identifying the mixtures that most commonly occur and cause adverse effects, and developing a regulatory structure capable of minimizing environmental impacts.
TL;DR: In this paper, the authors further validated two measures of creative imagination, and studied their relation to other creativity and personality measures, including the Urban and Jellen Test of Creative Thinking-Drawing Production (TCT-DP), an inventory of past creative accomplishments, a Thematic Appception Test (TAT) story, and scales for creative personality and the 5-factor model.
Abstract: This study sought to further validate two measures of creative imagination, and studied their relation to other creativity and personality measures. 151 college students completed the Urban and Jellen (1996) Test of Creative Thinking-Drawing Production (TCT-DP), an inventory of past creative accomplishments, a Thematic Apperception Test (TAT) story, and scales for creative personality and the 5-factor model. 86 of these participants also created autophotographic essays depicting themselves, scored for individuality/richness by consensual assessments. TCT-DP protocols were scored according to the manual, and also consensually assessed by teams of artist- and psychologist-judges. Factorial validity and relations to consensual assessments supported convergent and discriminant validity of the TCT-DP. The TCT-DP also correlated significantly with other creative products-the individuality of photo essays and rated creativity of TAT stories. Photo individuality correlated with past creative accomplishments in se...
TL;DR: The findings indicate that each Internet component satisfies slightly different needs, which can be predicted by some political attitudes and demographics, and Internet experience.
TL;DR: The authors explored impression and earnings management via reasoning and methods grounded in ethnostatistics and agency theory, and hypothesized that earnings management occurs more frequently following dual dual-entitlement models.
Abstract: We explore impression and earnings management via reasoning and methods grounded in ethnostatistics and agency theory. We hypothesized that earnings management occurs more frequently following dual...
TL;DR: In this paper, the authors examined the impact of education on income growth in India for the time period 1966-1996 and found that primary education has a strong causal impact on growth, with limited evidence of such an impact for secondary education.
TL;DR: It is hypothesize that VEGF165, produced by tumor cells, acts as an autocrine survival factor and that SEMA3B mediates its tumor-suppressing effects, at least in part, by blocking this V EGF autocrine activity.
Abstract: Semaphorin 3B (SEMA3B) is a secreted member of the semaphorin family, important in axonal guidance. We and others have shown that SEMA3B can act as a tumor suppressor by inducing apoptosis either by reexpression in tumor cells or applied as a soluble ligand. The common method of inactivation of SEMA3B is by allele loss and tumor-acquired promoter methylation. We studied the mechanism of SEMA3B-induced tumor cell apoptosis and found that vascular endothelial growth factor (VEGF)165 significantly decreased the proapoptotic and antimitotic effect of transfected or secreted SEMA3B on lung and breast cancer cells. VEGF165 binds to neuropilin, receptors for SEMA3B, and we found that SEMA3B competed for binding of 125I-VEGF165 to lung and breast cancer cells. We also found that small interfering RNA knockdown of tumor-produced VEGF-A or the use of an anti-VEGF neutralizing antibody (Ab) significantly inhibited tumor cell growth in vitro. By contrast, VEGF121, a VEGF variant that lacks binding to neuropilin (NP)-1 or NP-2 receptors, was not expressed in tumor cells and had no effect on SEMA3B growth-suppressing activities. In conclusion, we hypothesize that VEGF165, produced by tumor cells, acts as an autocrine survival factor and that SEMA3B mediates its tumor-suppressing effects, at least in part, by blocking this VEGF autocrine activity.
TL;DR: A careful analysis of elliptic curve point multiplication methods that use the point halving technique of Knudsen and Schroeppel is presented and an algorithm of Knuth is adapted to allow efficient use of projective coordinates with halving-based windowing methods for point multiplication.
Abstract: We present a careful analysis of elliptic curve point multiplication methods that use the point halving technique of Knudsen and Schroeppel and compare these methods to traditional algorithms that use point doubling. The performance advantage of halving methods is clearest in the case of point multiplication kP, where P is not known in advance and smaller field inversion to multiplication ratios generally favor halving. Although halving essentially operates on affine coordinate representations, we adapt an algorithm of Knuth to allow efficient use of projective coordinates with halving-based windowing methods for point multiplication.
TL;DR: This review focuses on phylogenetic relationships within each of the three divisions of bryophytes and relates morphological diversity to new insights about those relationships.
Abstract: The bryophytes comprise three phyla of embryophytes that are well established to occupy the first nodes among extant lineages in the land-plant tree of life. The three bryophyte groups (hornworts, liverworts, mosses) may not form a monophyletic clade, but they share life history features including dominant free-living gametophytes and matrotrophic monosporangiate sporophytes. Because of their unique vegetative and reproductive innovations and their critical position in embryophyte phylogeny, studies of bryophytes are crucial to understanding the evolution of land plant morphology and genomes. This review focuses on phylogenetic relationships within each of the three divisions of bryophytes and relates morphological diversity to new insights about those relationships. Most previous work has been on the mosses, but progress on understanding the phylogeny of hornworts and liverworts is advancing at a rapid pace. Multilocus multigenome studies have been successful at resolving deep relationships within the mosses and liverworts, whereas single-gene analyses have advanced understanding of hornwort evolution.