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1.
Evodevo ; 15(1): 8, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38918798

ABSTRACT

Studies of morphology and developmental patterning in adult stages of many invertebrates are hindered by opaque structures, such as shells, skeletal elements, and pigment granules that block or refract light and necessitate sectioning for observation of internal features. An inherent challenge in studies relying on surgical approaches is that cutting tissue is semi-destructive, and delicate structures, such as axonal processes within neural networks, are computationally challenging to reconstruct once disrupted. To address this problem, we developed See-Star, a hydrogel-based tissue clearing protocol to render the bodies of opaque and calcified invertebrates optically transparent while preserving their anatomy in an unperturbed state, facilitating molecular labeling and observation of intact organ systems. The resulting protocol can clear large (> 1 cm3) specimens to enable deep-tissue imaging, and is compatible with molecular techniques, such as immunohistochemistry and in situ hybridization to visualize protein and mRNA localization. To test the utility of this method, we performed a whole-mount imaging study of intact nervous systems in juvenile echinoderms and molluscs and demonstrate that See-Star allows for comparative studies to be extended far into development, facilitating insights into the anatomy of juveniles and adults that are usually not amenable to whole-mount imaging.

2.
Physiotherapy ; 124: 40-50, 2024 May 07.
Article in English | MEDLINE | ID: mdl-38870621

ABSTRACT

AIM: To explore the experiences of UK-based private physiotherapists when running and progressing a physiotherapy business. DESIGN: A hermeneutic phenomenological approach. PARTICIPANTS: Six UK-based private physiotherapy practice owners were recruited via purposive and snowball sampling. METHODS: In-depth, semi-structured video interviews (2 per participant), audio-recorded and transcribed. Field notes, respondent validation and a reflexive diary were used. Data underwent line-by-line analysis, identifying codes and themes. Constant comparison of data, codes and themes occurred throughout. Peer review was utilised, small sections of data and all emerging codes were independently reviewed. RESULTS: Three interconnecting themes. Working for myself: participants highlighted the freedom, flexibility and independence of business ownership, whilst acknowledging the additional pressures/challenges associated with this. Evolution of a practice: business growth was slow, requiring income supplementation initially. Successful growth often utilised luck and unexpected opportunities. Working with others: participants faced decisions regarding solo or joint ownership, when/what additional staff were required, whether staff should be employed or self-employed, and how to appropriately manage/support staff. CONCLUSIONS: Private practice ownership brings an array of benefits and challenges. Areas for future research include exploring the stresses of private roles and business ownership, the evolution of private physiotherapy practices, small-scale business partnerships, and employment vs self-employment. CONTRIBUTION OF THE PAPER.

3.
Nature ; 623(7987): 555-561, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37914929

ABSTRACT

The origin of the pentaradial body plan of echinoderms from a bilateral ancestor is one of the most enduring zoological puzzles1,2. Because echinoderms are defined by morphological novelty, even the most basic axial comparisons with their bilaterian relatives are problematic. To revisit this classical question, we used conserved anteroposterior axial molecular markers to determine whether the highly derived adult body plan of echinoderms masks underlying patterning similarities with other deuterostomes. We investigated the expression of a suite of conserved transcription factors with well-established roles in the establishment of anteroposterior polarity in deuterostomes3-5 and other bilaterians6-8 using RNA tomography and in situ hybridization in the sea star Patiria miniata. The relative spatial expression of these markers in P. miniata ambulacral ectoderm shows similarity with other deuterostomes, with the midline of each ray representing the most anterior territory and the most lateral parts exhibiting a more posterior identity. Strikingly, there is no ectodermal territory in the sea star that expresses the characteristic bilaterian trunk genetic patterning programme. This finding suggests that from the perspective of ectoderm patterning, echinoderms are mostly head-like animals and provides a developmental rationale for the re-evaluation of the events that led to the evolution of the derived adult body plan of echinoderms.


Subject(s)
Body Patterning , Echinodermata , Animals , Body Patterning/genetics , Gene Expression Regulation, Developmental , Transcription Factors/metabolism , Echinodermata/embryology , Echinodermata/genetics , Biological Evolution
5.
Physiotherapy ; 110: 1-4, 2021 03.
Article in English | MEDLINE | ID: mdl-33227546

ABSTRACT

BACKGROUND: The validity and reliability of pedometer software Apps versus the previously investigated spring lever and piezoelectric pedometers is unknown. PURPOSE: To evaluate the validity and reliability (in adults aged 18-65) of two pedometer software Apps, the Walk Star and the Accupedo, with spring lever (Digi-Walker CW 700) and piezoelectric (Omron HJ-720ITC and Tanita PD-724) pedometers in the measurement of step count. The criterion for comparison was researcher tallied direct observation of step count using an electronic E3-EHT hand held tally counter. METHODS: Eighteen participants walked for 5minutes on a treadmill at slow (2miles per hour) moderate (3miles per hour) and fast walking (4miles per hour) speeds and on urban streets and upon grass at a perceived "comfortable" walking speed. RESULTS: Bland and Altman plots show wide limits of agreement observed for the Yamax CW 700, Accupedo App and Walk Star App, suggesting these pedometers are unsuitable for measuring step counts in individuals due to high random error (indicating low reliability). Narrow limits of agreement were observed for the Omron HJ-720ITC and the Tanita PD-724 pedometers compared against Tally count and were considered suitable for use. CONCLUSION: The validity and reliability of pedometers cannot be assumed but must be tested and ensured before use in measuring step count.


Subject(s)
Actigraphy/instrumentation , Monitoring, Physiologic/instrumentation , Walking/physiology , Adolescent , Adult , Exercise Test , Female , Humans , Male , Middle Aged , Mobile Applications , Reproducibility of Results , Young Adult
6.
Osteoporos Int ; 30(7): 1403-1412, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31041474

ABSTRACT

Men and women with vertebral fractures due to osteoporosis are treated differently by society and health care professionals. This can lead to inequalities in health care and affects how men with fractures view themselves as people. We need to raise awareness that men get these fractures as well as women. INTRODUCTION: There is a lack of research exploring the experience of osteoporosis from the male perspective. This study was undertaken to explore and describe the experiences of men with vertebral fractures due to osteoporosis, including their perceptions of diagnosis, treatment and changes in their sense of self. METHODS: The study consists of in-depth semi-structured interviews with nine male participants of the PROVE (Physiotherapy Rehabilitation for Osteoporotic Vertebral Fracture) study. Interviews were digitally audio recorded and fully transcribed. Data were coded in accordance with an interpretative phenomenological analysis approach to analyses. RESULTS: Three main themes are presented. (i) Osteoporosis is considered an old women's disease. (ii) Men are diagnosed and treated differently than women in the NHS. Health care inequalities exist. (iii) Changes in self can occur in men after vertebral fracture/s due to osteoporosis. CONCLUSIONS: Greater awareness that men get this condition is needed in both society in general and also by health care professionals who often do not expect osteoporosis to affect men. Approaches to diagnosis and treatment need to be considered and improved to ensure that they become appropriate and effective for men as well as women.


Subject(s)
Attitude to Health , Healthcare Disparities/statistics & numerical data , Osteoporosis/psychology , Osteoporotic Fractures/psychology , Spinal Fractures/psychology , Aged , Aged, 80 and over , Attitude of Health Personnel , England , Humans , Interviews as Topic , Male , Men's Health , Middle Aged , Osteoporosis/complications , Osteoporosis/diagnosis , Osteoporosis/therapy , Osteoporotic Fractures/diagnosis , Osteoporotic Fractures/etiology , Qualitative Research , Sex Factors , Sexism , Spinal Fractures/etiology
7.
Arch Osteoporos ; 11(1): 33, 2016 12.
Article in English | MEDLINE | ID: mdl-27739032

ABSTRACT

We aimed to systematically review qualitative studies exploring the experience of living with osteoporosis to develop new conceptual understanding. We identified themes about the invisibility/visibility of osteoporosis, the experience of uncertainty of living with osteoporosis (OP) and living with an ageing body and the place of gender. PURPOSE: The aim of this review was to systematically review the body of qualitative studies exploring the experience of living with either osteoporosis or osteopenia and to use meta-ethnography to develop new conceptual understanding. METHODS: We systematically reviewed and integrated the findings of qualitative research from four bibliographic databases (Medline, Embase, Cinahl, Psychinfo) to September 2015 in order to increase our conceptual understanding of the lived experience of osteoporosis and osteopenia. Articles were appraised for quality; each was independently read by two researchers to identify concepts which were compared and developed into a conceptual model. RESULTS: Our findings demonstrate that coming to terms with a diagnosis of osteoporosis is linked to its relative visibility or invisibility. For some, OP has not become manifest and self-identity is intact (biographical integrity). For others, OP is profoundly manifest and self-identity is no long intact (biographical fracture). We also demonstrate that overwhelming uncertainty pervades the experience of OP. Our final theme demonstrates how the experience of OP is set within a cultural context with certain views about ageing and gender. CONCLUSIONS: Our synthesis has highlighted the wealth of qualitative data about osteoporosis and osteopenia. Despite the increasing body of literature on the subject, there remains a need to adjust our interactions with patients. This will allow clinicians to understand how patients can be helped to receive and understand their diagnosis and move forward in partnership with healthcare providers to promote optimal management of the disease.


Subject(s)
Aging , Osteoporosis , Uncertainty , Aging/physiology , Aging/psychology , Anthropology, Cultural/methods , Humans , Life Change Events , Osteoporosis/ethnology , Osteoporosis/psychology , Professional-Patient Relations , Qualitative Research , United Kingdom
8.
Mar Genomics ; 24 Pt 2: 177-83, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26472700

ABSTRACT

Opsins--G-protein coupled receptors involved in photoreception--have been extensively studied in the animal kingdom. The present work provides new insights into opsin-based photoreception and photoreceptor cell evolution with a first analysis of opsin sequence data for a major deuterostome clade, the Ambulacraria. Systematic data analysis, including for the first time hemichordate opsin sequences and an expanded echinoderm dataset, led to a robust opsin phylogeny for this cornerstone superphylum. Multiple genomic and transcriptomic resources were surveyed to cover each class of Hemichordata and Echinodermata. In total, 119 ambulacrarian opsin sequences were found, 22 new sequences in hemichordates and 97 in echinoderms (including 67 new sequences). We framed the ambulacrarian opsin repertoire within eumetazoan diversity by including selected reference opsins from non-ambulacrarians. Our findings corroborate the presence of all major ancestral bilaterian opsin groups in Ambulacraria. Furthermore, we identified two opsin groups specific to echinoderms. In conclusion, a molecular phylogenetic framework for investigating light-perception and photobiological behaviors in marine deuterostomes has been obtained.


Subject(s)
Chordata, Nonvertebrate/genetics , Echinodermata/genetics , Evolution, Molecular , Opsins/metabolism , Phylogeny , Amino Acid Sequence , Animals , Gene Expression Regulation , Models, Molecular , Molecular Sequence Data , Opsins/genetics , Protein Conformation
9.
Clin Rehabil ; 25(3): 264-74, 2011 Mar.
Article in English | MEDLINE | ID: mdl-20971749

ABSTRACT

OBJECTIVES: (1) To develop trial protocols which promote the achievement of blind outcome assessment. (2) To report outcome assessor beliefs regarding group allocation at follow-up assessments. (3) To document and describe instances of unblinding occurring during the trial to assist and inform rehabilitation researchers and clinicians. DESIGN: Prospective longitudinal observational study. SETTING: An NHS Hospital Trust specializing in orthopaedic surgery. SUBJECTS: One hundred and seven patients participating in a prospective pragmatic randomized controlled trial investigating physiotherapy rehabilitation following total knee arthroplasty, plus three outcome assessors. INTERVENTIONS: A protocol was developed using available research and designed to minimize instances of unblinding during a physiotherapy rehabilitation trial. Administrative, office, patient and research staff procedures were included. MAIN MEASURES: Trial questionnaires measured blind outcome assessment responses at 3 and 12 months post surgery. The outcome assessor kept a field diary recording the events surrounding instances of unblinding. Data underwent descriptive and content analysis. RESULTS: Blind outcome assessment was believed successful for n = 74 (81.32%) assessments at 3-month follow-up, and n = 83 (91.21%) at 12 months. Forty instances (n = 28 participants) of unblinding were described in the field diary. While the main cause of unblinding was participants telling the outcome assessor, in 12.5% of events the assessor drew the wrong conclusion regarding group allocation. Not all unblinding events were remembered at subsequent assessments, even in this relatively small trial. CONCLUSIONS: Blind outcome assessment was considered achievable in this trial. Specific trial protocols enabled blinding beliefs to be reported and instances of unblinding to be described.


Subject(s)
Arthroplasty, Replacement, Knee/rehabilitation , Osteoarthritis, Knee/rehabilitation , Outcome and Process Assessment, Health Care , Physical Therapy Modalities , Randomized Controlled Trials as Topic , Arthroplasty, Replacement, Knee/methods , Double-Blind Method , Female , Humans , Longitudinal Studies , Male , Osteoarthritis, Knee/surgery , Prospective Studies , Reproducibility of Results , Single-Blind Method , Surveys and Questionnaires , United Kingdom
10.
Biol Bull ; 214(3): 284-302, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18574105

ABSTRACT

We describe a collection of expressed sequence tags (ESTs) for Saccoglossus kowalevskii, a direct-developing hemichordate valuable for evolutionary comparisons with chordates. The 202,175 ESTs represent 163,633 arrayed clones carrying cDNAs prepared from embryonic libraries, and they assemble into 13,677 continuous sequences (contigs), leaving 10,896 singletons (excluding mitochondrial sequences). Of the contigs, 53% had significant matches when BLAST was used to query the NCBI databases (< or = 10(-10)), as did 51% of the singletons. Contigs most frequently matched sequences from amphioxus (29%), chordates (67%), and deuterostomes (87%). From the clone array, we isolated 400 full-length sequences for transcription factors and signaling proteins of use for evolutionary and developmental studies. The set includes sequences for fox, pax, tbx, hox, and other homeobox-containing factors, and for ligands and receptors of the TGFbeta, Wnt, Hh, Delta/Notch, and RTK pathways. At least 80% of key sequences have been obtained, when judged against gene lists of model organisms. The median length of these cDNAs is 2.3 kb, including 1.05 kb of 3' untranslated region (UTR). Only 30% are entirely matched by single contigs assembled from ESTs. We conclude that an EST collection based on 150,000 clones is a rich source of sequences for molecular developmental work, and that the EST approach is an efficient way to initiate comparative studies of a new organism.


Subject(s)
Intracellular Signaling Peptides and Proteins/genetics , Transcription Factors/genetics , 3' Untranslated Regions , Animals , Expressed Sequence Tags , Gene Library , Open Reading Frames , Phylogeny , Sequence Analysis, DNA , Sequence Homology
11.
Integr Comp Biol ; 46(6): 890-901, 2006 Dec.
Article in English | MEDLINE | ID: mdl-21672793

ABSTRACT

The evolutionary origins of the chordate central nervous system remain uncertain. Conclusions drawn from classical morphological comparisons and from a broad range of metazoan phyla conflict with the new molecular genetic information from developmental model systems characterized by central nervous systems. This has led to debate as to the nature of the ancestral deuterostome nervous system. Hemichordates as basal deuterostomes occupy a phylogenetically critical position for addressing hypotheses on the evolution of the chordate nervous system. Characterizing the molecular basis of the development of their diffuse nervous system offers insights into the role of conserved body patterning genes in the evolution of specific neural anatomies. We present a description of hox gene expression during the development of the direct-developing hemichordate Saccoglossus kowalevskii. The nested ectodermal expression of these genes in a hemichordate suggest that they play a general patterning role in the anterior/posterior regionalization of the ectoderm of bilaterians rather than being uniquely associated with the development and evolution of central nervous systems.

13.
BMJ ; 323(7325): 1340-3, 2001 Dec 08.
Article in English | MEDLINE | ID: mdl-11739221

ABSTRACT

OBJECTIVE: To determine whether a pharmacist can effectively review repeat prescriptions through consultations with elderly patients in general practice. DESIGN: Randomised controlled trial of clinical medication review by a pharmacist against normal general practice review. SETTING: Four general practices. PARTICIPANTS: 1188 patients aged 65 or over who were receiving at least one repeat prescription and living in the community. INTERVENTION: Patients were invited to a consultation at which the pharmacist reviewed their medical conditions and current treatment. MAIN OUTCOME MEASURES: Number of changes to repeat prescriptions over one year, drug costs, and use of healthcare services. RESULTS: 590 (97%) patients in the intervention group were reviewed compared with 233 (44%) in the control group. Patients seen by the pharmacist were more likely to have changes made to their repeat prescriptions (mean number of changes per patient 2.2 v 1.9; difference=0.31, 95% confidence interval 0.06 to 0.57; P=0.02). Monthly drug costs rose in both groups over the year, but the rise was less in the intervention group (mean difference 4.72 pound sterling per 28 days, - 7.04 pound sterling to - 2.41 pound sterling); equivalent to 61 pound sterling per patient a year. Intervention patients had a smaller rise in the number of drugs prescribed (0.2 v 0.4; mean difference -0.2, -0.4 to -0.1). There was no evidence that review of treatment by the pharmacist affected practice consultation rates, outpatient consultations, hospital admissions, or death rate. CONCLUSIONS: A clinical pharmacist can conduct effective consultations with elderly patients in general practice to review their drugs. Such review results in significant changes in patients' drugs and saves more than the cost of the intervention without affecting the workload of general practitioners.


Subject(s)
Patient Participation , Pharmacists , Practice Patterns, Physicians' , Aged , Drug Costs , Drug Prescriptions , Female , Humans , Interviews as Topic , Male , Patient Acceptance of Health Care
14.
Pharm World Sci ; 23(1): 22-7, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11344587

ABSTRACT

OBJECTIVES: To compare the population consenting for a study of the effectiveness of a pharmacist-run medication review clinic with the population not consenting for patients aged over 65 years old with respect to age, sex and number of repeat medicines. To explore the reasons why some patients declined to consent to the study. METHODS: Letters were sent to 2,403 patients aged 65 and over and taking at least one repeat medicine from 4 general practices. If no reply was received to a second letter they were followed up by telephone. If they declined to consent they were asked for their reasons. Data for consenting and non-consenting patients was collected on the stratification factors: age, sex and number of repeat medicines. Multiple logistic regression was used to assess the association of each factor with consent rates. RESULTS: Consenting patients were dissimilar to non-consenting patients. Patients were less likely to consent if they were older, OR (95% CI) = 0.54 (0.46, 0.64), or female, OR (95% CI) = 0.74 (0.63, 0.88). Patients were more likely to consent if on 5 or more repeat medicines: OR (95% CI) = 1.3 (1.1, 1.5). Ten broad categories of reasons why patients did not wish to participate were identified from the patient interviews. CONCLUSIONS: Patients were less likely to give their consent if they were elderly, female and on fewer repeat medicines. A number of administrative and behavioural factors were identified which reduced the chances of informed consent being given. These factors need to be addressed to maximise numbers of consenting patients in medication review studies.


Subject(s)
Aged/psychology , Clinical Trials as Topic/psychology , Attitude , Data Collection , Drug Therapy , Female , Humans , Logistic Models , Male , Odds Ratio , Pharmaceutical Preparations/administration & dosage , Physician-Patient Relations
15.
Pharm World Sci ; 22(4): 121-6, 2000 Aug.
Article in English | MEDLINE | ID: mdl-11103380

ABSTRACT

Medication review of patients on long-term treatment in general practice in the UK has been reported to be inadequate. Proposals followed suggesting that pharmacists could use their expertise to lead such a medication review in conjunction with the general practitioner. This paper describes the concept of clinical medication review by a pharmacist based in general practice. We describe the development of a method for a structured and systematic process for undertaking such a review in clinics conducted by a pharmacist. The method was developed for a nationally funded study in the UK. We provide a definition of clinical medication review and suggests a structure for the process through data gathering, evaluation and implementation.


Subject(s)
Drug Therapy , Family Practice , Pharmacists , Communication , Humans
16.
Br J Clin Pharmacol ; 50(2): 172-5, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10930970

ABSTRACT

AIMS: To determine whether a medicine review and education programme influences the compliance and knowledge of older people in general practice. METHODS: Older people taking at least three medicines were randomly allocated to a control or intervention group. Both groups received three visits from a clinical pharmacist: Visit 1: Assessment and patients' medicines rationalized in intervention group. Visit 2: Intervention group given medicines education. Visit 3: Knowledge and compliance in both groups assessed by structured questionnaire RESULTS: Compliance in the intervention group was 91.3%, compared with 79.5% in the control group (P < 0.0001). The number of intervention group patients correctly understanding the purpose of their medicines increased from 58% to 88% on the second visit, compared with 67% to 70% in the control group (P < 0.0005). CONCLUSIONS: A general practice based medication review and education programme improved medicine compliance and knowledge of older people in the short term.


Subject(s)
Medication Systems , Patient Compliance/psychology , Patient Education as Topic , Pharmacists , Aged , Aged, 80 and over , Chi-Square Distribution , Confidence Intervals , Family Practice , Female , Humans , Male , Patient Education as Topic/methods , Pharmacists/psychology , Statistics, Nonparametric
18.
Syst Biol ; 49(1): 28-51, 2000 Mar.
Article in English | MEDLINE | ID: mdl-12116481

ABSTRACT

Modified interactions among developmental regulatory genes and changes in their expression domains are likely to be an important part of the developmental basis for evolutionary changes in morphology. Although developmental regulatory genes are now being studied in an increasing number of taxa, there has been little attempt to analyze the resulting data within an explicit phylogenetic context. Here we present comparative analyses of expression data from regulatory genes in the phylum Echinodermata, considering the implications for understanding both echinoderm evolution as well as the evolution of regulatory genes in general. Reconstructing the independent evolutionary histories of regulatory genes, their expression domains, their developmental roles, and the structures in which they are expressed reveals a number of distinct evolutionary patterns. A few of these patterns correspond to interpretations common in the literature, whereas others have received little prior mention. Together, the analyses indicate that the evolution of echinoderms involved: (1) the appearance of many apomorphic developmental roles and expression domains, some of which have plesiomorphic bilateral symmetry and others of which have apomorphic radial symmetry or left-right asymmetry; (2) the loss of some developmental roles and expression domains thought to be plesiomorphic for Bilateria; and (3) the retention of some developmental roles thought to be plesiomorphic for Bilateria, although with modification in expression domains. Some of the modifications within the Echinodermata concern adult structures; others, transient larval structures. Some changes apparently appeared early in echinoderm evolution (> 450 Ma), whereas others probably happened more recently (< 50 Ma). Cases of likely convergence in expression domains suggest caution when using developmental regulatory genes to make inferences about homology among morphological structures of distantly related taxa.


Subject(s)
Biological Evolution , Echinodermata/genetics , Genes, Regulator , Phylogeny , Animals , Echinodermata/classification
19.
Am J Clin Oncol ; 20(5): 509-10, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9345338

ABSTRACT

Hepatocellular carcinoma (HCC) spreading to the pancreas is rare and, when it does occur, is most often detected as a late finding at autopsy. We report the first case of HCC initially presenting as a pancreatic mass. Computed tomography (CT) scan showed a 7-cm mass in the dome of the liver and a 3-cm pancreatic head mass causing biliary and duodenal obstruction. Palliative surgery was performed to bypass the pancreatic obstruction. During the operation, fine needle aspiration (FNA) was performed on the pancreatic mass. The liver mass was sampled by percutaneous ultrasound-guided biopsy. Postoperatively, the patient's obstructive symptoms were relieved. The histologic studies showed that both the liver and the pancreatic masses consisted of poorly differentiated HCC that stained positive for alpha-fetoprotein. The rarity and the implications of this presentation are discussed.


Subject(s)
Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , Pancreatic Neoplasms/secondary , Biopsy, Needle , Carcinoma, Hepatocellular/secondary , Carcinoma, Hepatocellular/surgery , Cholestasis/etiology , Diagnosis, Differential , Duodenal Obstruction/etiology , Hepatectomy , Humans , Liver Neoplasms/surgery , Male , Middle Aged , Palliative Care , Pancreatectomy , Pancreatic Neoplasms/pathology , Pancreatic Neoplasms/surgery , Tomography, X-Ray Computed , Ultrasonography, Interventional , alpha-Fetoproteins/analysis
20.
Nature ; 389(6652): 718-21, 1997 Oct 16.
Article in English | MEDLINE | ID: mdl-9338781

ABSTRACT

Echinoderms possess one of the most highly derived body architectures of all metazoan phyla, with radial symmetry, a calcitic endoskeleton, and a water vascular system. How these dramatic morphological changes evolved has been the subject of extensive speculation and debate, but remains unresolved. Because echinoderms are closely related to chordates and postdate the protostome/deuterostome divergence, they must have evolved from bilaterally symmetrical ancestors. Here we report the expression domains in echinoderms of three important developmental regulatory genes (distal-less, engrailed and orthodenticle), all of which encode transcription factors that contain a homeodomain. Our findings show that the reorganization of body architecture involved extensive changes in the deployment and roles of homeobox genes. These changes include modifications in the symmetry of expression domains and the evolution of several new developmental roles, as well as the loss of roles conserved between arthropods and chordates. Some of these modifications seem to have evolved very early in the history of echinoderms, whereas others probably evolved during the subsequent diversification of adult and larval morphology. These results demonstrate the evolutionary lability of regulatory genes that are widely viewed as conservative.


Subject(s)
Biological Evolution , Echinodermata/genetics , Genes, Homeobox , Transcription Factors , Animals , Body Patterning/genetics , Drosophila Proteins , Echinodermata/embryology , Evolution, Molecular , Gene Expression , Genes, Regulator , Homeodomain Proteins/genetics
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