Do Crowding-Out Effects Explain the Low Effect of a Health Promotion Intervention among Young People at a Vocational School?

In recent years, school-based interventions have increasingly been used as a strategy to promote good eating habits and physical activity among young people at school. However, little is known about the effect that this kind of public involvement has on the overall behavior of young people. Economists refer to the existence of a crowding-out effect when public sector engagement in influencing behavior is counteracted by behaviors at the individual level. The aim of this study was to investigate the effects of a health promotion intervention program among young people at a vocational school on the overall behavior of the students and consider whether a crowding-out effect existed when it came to health behavior. This study used data from the Gearing up the Body (GUB) intervention that was carried out at the vocational school of Uddannelsescenter Holstebro, Denmark. The study included 130 students from two vocational programs. Answers were collected from survey questions in three waves. Our results showed that intervening in the school setting had the intended impact on physical activity but an unintended impact on eating behavior. In the GUB study, we found signs of countervailing behaviors in and out of school that need to be further explored.

Does It Run in the Family? How Family Background Affects Attachment Styles for Students in Higher Education.

BACKGROUND: Socioeconomic background has traditionally been the most important determinant of an individual's social advantage. Studies have used social class and opportunities based on parental income and education to predict such advantage. There is limited evidence that stratification mechanisms other than socioeconomic background can play an important role. The purpose of the study is to examine the influence of the traditional factors (income and education) of family background on students' social attachment styles compared to other background variables (civil status and number of children). METHODS: We used the Vulnerable Attachment Style Questionnaire as an outcome measure to assess students' social attachment advantage. As a point of departure, we use theories of social psychology to categorize social relations in terms of secure or insecure bonding, respectively. RESULTS: A cross-sectional data set of 912 university students from five European countries was used. With respect to social attachment, the likelihood of being a student with robust relations increases by 23% if the students have high-income parents. Students with robust relations also have a decreased likelihood of poor body self-esteem by 19% when compared with other students. CONCLUSIONS: Stratification mechanisms other than social class, such as parental characteristics, civil status, and number of siblings, all affect the privileged students' social relations.

Responsible Governance for a Food and Nutrition E-Infrastructure: Case Study of the Determinants and Intake Data Platform.

The focus of the current paper is on a design of responsible governance of food consumer science e-infrastructure using the case study Determinants and Intake Data Platform (DI Data Platform). One of the key challenges for implementation of the DI Data Platform is how to develop responsible governance that observes the ethical and legal frameworks of big data research and innovation, whilst simultaneously capitalizing on huge opportunities offered by open science and the use of big data in food consumer science research. We address this challenge with a specific focus on four key governance considerations: data type and technology; data ownership and intellectual property; data privacy and security; and institutional arrangements for ethical governance. The paper concludes with a set of responsible research governance principles that can inform the implementation of DI Data Platform, and in particular: consider both individual and group privacy; monitor the power and control (e.g., between the scientist and the research participant) in the process of research; question the veracity of new knowledge based on big data analytics; understand the diverse interpretations of scientists' responsibility across different jurisdictions.

Validation of a novel image-weighed technique for monitoring food intake and estimation of portion size in hospital settings: a pilot study.

OBJECTIVE: Optimal nutrition for hospital patients is crucial and routine monitoring of patients' nutrient intake is imperative. However, personalised monitoring and customised intervention using traditional methods is challenging and labour-intensive, consequently it is often neglected in hospital settings. The present pilot study aimed to examine the reliability and validity of the Dietary Intake Monitoring System (DIMS) against the weighed food method (WFM). DESIGN: The DIMS 2.0 is composed of an integrated digital camera, weighing scale, radio-frequency identification sensor and WIFI connection for real-time image and weight dietary data acquisition and analysis. The DIMS equipment was used to collect data for a paired set of meals both before and after meal consumption at lunchtime. SETTING: Odense University Hospital, Denmark. SUBJECTS: Photos and weights of seventeen patient meals were captured. RESULTS: The results showed a significant correlation between DIMS and WFM for energy (r=0·99, P<0·01) and protein intake (r=0·98, P<0·01). Intraclass correlation coefficients (ICC) revealed a high degree of agreement among the four non-trained assessors for estimates of portion size of each food item before (0·88, P<0·01) and after consumption (0·99, P<0·01). The ICC for energy and protein intake were 0·99 (P<0·01) and 0·99 (P<0·01), respectively. Bland-Altman plots revealed no systematic bias. CONCLUSIONS: Considering the huge benefits associated with routine monitoring, technological advances have made it possible to develop a novel, easy-to-use DIMS that, according to the findings, is a valid alternative for use in hospital settings.

Substituting sugar confectionery with fruit and healthy snacks at checkout - a win-win strategy for consumers and food stores? a study on consumer attitudes and sales effects of a healthy supermarket intervention.

BACKGROUND: The widespread use of in-store marketing strategies to induce unhealthy impulsive purchases has implications for shopping experience, food choice and possibly adverse health outcomes. The aim of this study was to examine consumer attitudes and evaluate sales effects of a healthy checkout supermarket intervention. The study was part of Project Sundhed & Lokalsamfund (Project SoL); a Danish participatory community-based health promotion intervention. METHODS: Consumer attitudes towards unhealthy snack exposure in supermarkets were examined in a qualitative pre-intervention study (29 short in-store interviews, 11 semi-structured interviews and three focus group interviews). Findings were presented to food retailers and informed the decision to test a healthy checkout intervention. Sugar confectionery at one checkout counter was substituted with fruit and healthy snacking items in four stores for 4 weeks. The intervention was evaluated by 48 short exit interviews on consumer perceptions of the intervention and by linear mixed model analyses of supermarket sales data from the intervention area and a matched control area. RESULTS: The qualitative pre-intervention study identified consumer concern and annoyance with placement and promotion of unhealthy snacks in local stores. Store managers were willing to respond to local consumer concern and a healthy checkout intervention was therefore implemented. Exit interviews found positive attitudes towards the intervention, while intervention awareness was modest. Most participants believed that the intervention could help other consumers make healthier choices, while fewer expected to be influenced by the intervention themselves. Statistical analyses suggested an intervention effect on sales of carrot snack packs when compared with sales before the intervention in Bornholm control stores (P < 0.05). No significant intervention effect on sales of other intervention items or sugar confectionery was found. CONCLUSIONS: The present study finds that the healthy checkout intervention was positively evaluated by consumers and provided a 'responsible' branding opportunity for supermarkets, thus representing a win-win strategy for store managers and consumers in the short term. However, the intervention was too modest to draw conclusions on long-term sales and health implications of this initiative. More research is needed to assess whether retailer-researcher collaborations on health promotion can be a winning strategy for public health.

BRCA1/2 testing in newly diagnosed breast and ovarian cancer patients without prior genetic counselling: the DNA-BONus study.

Germline BRCA1/2 testing of breast and ovarian cancer patients is growing rapidly as the result affects both treatment and cancer prevention in patients and relatives. Through the DNA-BONus study we offered BRCA1/2 testing and familial risk assessment to all new patients with breast (N=893) or ovarian (N=122) cancer diagnosed between September 2012 and April 2015, irrespective of family history or age, and without prior face-to-face genetic counselling. BRCA1/2 testing was accepted by 405 (45.4%) and 83 (68.0%) of the patients with breast or ovarian cancer, respectively. A pathogenic BRCA1/2 variant was found in 7 (1.7%) of the breast cancer patients and 19 (22.3%) of the ovarian cancer patients. In retrospect, all BRCA1/2 mutation carriers appeared to fulfill current criteria for BRCA1/2 testing. Hospital Anxiety and Depression Scale (HADS) scores showed that the mean levels of anxiety and depression were comparable to those reported for breast and gynecological cancer patients in general, with a significant drop in anxiety symptoms during a 6-month follow-up period, during which the test result was forwarded to the patients. These results show that BRCA1/2 testing is well accepted in newly diagnosed breast and ovarian cancer patients. Current test criteria based on age and family history are sufficient to identify most BRCA1/2 mutation carriers among breast cancer patients. We recommend germline BRCA1/2 testing in all patients with epithelial ovarian cancer because of the high prevalence of pathogenic BRCA1/2 variants.

Defining Neighbourhoods as a Measure of Exposure to the Food Environment.

Neighbourhoods are frequently used as a measure for individuals' exposure to the food environment. However, the definitions of neighbourhoods fluctuate and have not been applied consistently in previous studies. Neighbourhoods defined from a single fixed location fail to capture people's complete exposure in multiple locations, but measuring behaviour using traditional methods can be challenging. This study compares the traditional methods of measuring exposure to the food environment to methods that use data from GPS tracking. For each of the 187 participants, 11 different neighbourhoods were created in which the exposure to supermarkets and fast food outlets were measured. ANOVA, Tukey's Honestly Significant Difference (HSD) test and t-tests were performed to compare the neighbourhoods. Significant differences were found between area sizes and the exposure to supermarkets and fast food outlets for different neighbourhood types. Second, significant differences in exposure to food outlets were found between the urban and rural neighbourhoods. Neighbourhoods are clearly a diffused and blurred concept that varies in meaning depending on each person's perception and the conducted study. Complexity and heterogeneity of human mobility no longer appear to correspond to the use of residential neighbourhoods but rather emphasise the need for methods, concepts and measures of individual activity and exposure.

The association between organic school food policy and school food environment: results from an observational study in Danish schools.

AIMS: School food in many countries has become the object of change and innovation processes, not only in relation to policies for healthier eating but also in relation to policies for more sustainable food consumption and procurement. The purpose of this study was to examine the possible influence that organic food sourcing policies in Danish school meal systems may have on the development of healthier school food environments. METHODS: The study was a cross-sectional analysis undertaken among 179 school food coordinators (SFCs) through a web-based questionnaire (WBQ) in a sample of Danish public primary schools. The 'organic' schools were compared to 'non-organic' schools. The questionnaire explored the attitudes, intentions/policies and actions in relation to organic and healthy foods served in the schools. RESULTS: Data indicates that 20 'organic' schools were associated with the indicators of healthier school environments, including adopting a Food and Nutrition Policy (FNP) in the school (p = .032), recommending children to eat healthily (p = .004). CONCLUSIONS: The study suggests that organic food policies in schools may have potential to support a healthier school food environment.

Do attitudes, intentions and actions of school food coordinators regarding public organic food procurement policy improve the eating environment at school? Results from the iPOPY study.

OBJECTIVE: The present study investigates whether public organic food procurement policies have the potential to induce changes in the school food service environment. DESIGN: A comparative cross-national survey was conducted in public primary and/or secondary schools in Finland, Germany and Italy. The school food coordinators completed a web-based questionnaire on their attitudes, intentions and actions towards organic school food provision. SETTING: In Germany, 122 out of 2050 schools in the state of Hesse responded. In Finland, 250 out of 998 schools across the country responded. In Italy, 215 out of 940 schools from eight provinces responded. SUBJECTS: School food coordinators in the sample of schools in the three countries. RESULTS: The German and Finnish school food coordinators separately most agreed with the promotion of healthy eating habits (P < 0·001) and organic food (P < 0·001) by schools. The Finnish schools were most likely to adopt a food and nutrition policy (P < 0·001), a health-promoting school policy according to WHO principles (P < 0·001), to have a playground (P < 0·001), to involve physical activity themes in teaching (P = 0·012) and to have a canteen (P < 0·001). The Italian schools were most likely to involve the food and nutrition policy in pedagogical activities (P = 0·004), to serve nutritional school meals (P < 0·001) and to recommend children to eat healthily (P < 0·001). In the three countries, the non-organic schools were less likely to adopt a food and nutrition policy (P < 0·001), a WHO health-promoting policy (P < 0·001) and have a canteen (P = 0·017) than the organic schools. CONCLUSIONS: The study suggests that there is a gap in the effects of public organic food procurement policy on building a healthier school food environment.

Understanding hospital meal experiences by means of participant-driven-photo-elicitation.

A patients' hospital meal experiences can be complex and often difficult to capture using traditional methods. This study investigated patients' hospital meal experiences using participant-driven-photo-elicitation (PDPE). PDPE invites respondents to photograph their daily lives and combines this with interviews, which can provide deeper insight into multisensory experiences beyond verbal or written discourse. The sample consisted of eight hospitalised patients. Patients completed a photo-essay of their hospital meal experience during a single day at a Danish hospital and afterwards participated in an open-ended interview. Two inductive analytical approaches were selected to assess the patients' reflections on their hospital meal experiences. First, the interview transcripts were analysed using the Semiotic Analysis approach using qualitative data analysis software NVivo 9. Second, the 91 produced photographs and the participants' engagement with the photographs were analysed by means of a Reflexive Content Analysis. The study found that PDPE is a research method that can be used for expanding the conceptualisation of hospital meal experiences, revealing the significance of the meal context, materiality and memories beyond food per se.

Physical activity and play in kindergarten age children.

PERISCOPE project assesses factors promoting or preventing obesity development in early age. A specific aim is to assess preschool children's physical activity habits in three different European countries. PERISCOPE has been implemented in 1094 children attending kindergartens in Denmark, Italy and Poland. The parents' and children's physical activity habits and attitudes assessed by a questionnaire filled by the parents. Overweight and obesity assessed by Cole's BMI cut-off points. Statistical analysis performed by χ(2) test and the test of proportion. Denmark shows the lowest rate (14.6 %) of overweight, followed by Poland (17.1%), while Italy shows the highest (21.2 %) (p < 0.0001). The Polish families show the highest rate of walking from home to kindergarten and back, followed by the Italians and, lastly, the Danish ones (p < 0.001). Almost all the Danish and Polish children, but only the 50.1 % of the Italians play outside (p < 0.001). During the weekdays, 34.9 % of Polish children, 22.2 % of Italians and 19.8 % of the Danish play outside more than one hour a day (p < 0.0001). During the weekend, 91.1 % of Polish children, 86.7 % of Danish children, but only 54.4 % of Italians play outside more than one hour (p < 0.0001). 53.5 % of Danish children, 31.9 % of Polish children, and 18.2 % of Italian ones practice sport (p < 0.0001). Danish children are the most active, the Polish are in the middle and the Italians are the least active. The difference in infrastructures (safety of walking streets, access to playgrounds/parks, etc.) can play an important role, in addition to cultural and social family characteristics, to the development of overweight.

Long-term sustainability of a worksite canteen intervention of serving more fruit and vegetables.

OBJECTIVE: To analyse the 5-year sustainability of a worksite canteen intervention of serving more fruit and vegetables (F&V). DESIGN: Average F&V consumption per customer per meal per day was assessed in five worksite canteens by weighing F&V served and subtracting waste. Data were collected by the canteen staff during a 3-week continuous period and compared to data from the same five canteens measured at baseline, at end point and at 1-year follow-up. The intervention used a participatory and empowering approach, self-monitoring and networking among the canteen staff, management and a consultant. The method focused on providing ideas for increased F&V for lunch, making environmental changes in the canteens by giving access to tasteful and healthy food choices and reducing the availability of unhealthy options. SETTING: Five Danish worksites serving from 50 to 500 meals a day: a military base, an electronic component distributor, a bank, a town hall and a waste-handling facility. SUBJECTS: Worksite canteen managers, canteen staff. RESULTS: Four of the five worksite canteens were able to either maintain the intervention or even increase the consumption of F&V. The average increase from baseline to 5-year follow-up was 95 g per customer per meal per day (18, 144, 66, 105 and 141 g, respectively). On average, the five canteens at the long-term follow-up had an F&V consumption of 208 g/meal per customer. CONCLUSIONS: The present study indicates that sustainability of F&V is possible in worksites where the participatory and empowering approach, self-monitoring, environmental change, dialogue with suppliers and networking among worksite canteens are applied.

Detection and Investigation of Soil Biological Activity against Meloidogyne incognita.

Greenhouse experiments with two susceptible hosts of Meloidogyne incognita, a dwarf tomato and wheat, led to the identification of a soil in which the root-knot nematode population was reduced 5- to 16-fold compared to identical but pasteurized soil two months after infestation with 280 M. incognita J2/100 cm(3) soil. This suppressive soil was subjected to various temperature, fumigation and dilution treatments, planted with tomato, and infested with 1,000 eggs of M. incognita/100 cm(3) soil. Eight weeks after nematode infestation, distinct differences in nematode population densities were observed among the soil treatments, suggesting the suppressiveness had a biological nature. A fungal rRNA gene analysis (OFRG) performed on M. incognita egg masses collected at the end of the greenhouse experiments identified 11 fungal phylotypes, several of which exhibited associations with one or more of the nematode population density measurements (egg masses, eggs or J2). The phylotype containing rRNA genes with high sequence identity to Pochonia chlamydosporia exhibited the strongest negative associations. The negative correlation between the densities of the P. chlamydosporia genes and the nematodes was corroborated by an analysis using a P. chlamydosporia-selective qPCR assay.

Bird evolution in the Eocene: climate change in Europe and a Danish fossil fauna.

The pattern of the evolutionary radiation of modern birds (Neornithes) has been debated for more than 10 years. However, the early fossil record of birds from the Paleogene, in particular, the Lower Eocene, has only recently begun to be used in a phylogenetic context to address the dynamics of this major vertebrate radiation. The Cretaceous-Paleogene (K-P) extinction event dominates our understanding of early modern bird evolution, but climate change throughout the Eocene is known to have also played a major role. The Paleocene and Lower Eocene was a time of avian diversification as a result of favourable global climatic conditions. Deteriorations in climate beginning in the Middle Eocene appear to be responsible for the demise of previously widespread avian lineages like Lithornithiformes and Gastornithidae. Other groups, such as Galliformes display replacement of some lineages by others, probably related to adaptations to a drier climate. Finally, the combination of slowly deteriorating climatic conditions from the Middle Eocene onwards, appears to have slowed the evolutionary rate in Europe, as avian faunas did not differentiate markedly until the Oligocene. Taking biotic factors in tandem with the known Paleogene fossil record of Neornithes has recently begun to illuminate this evolutionary event. Well-preserved fossil taxa are required in combination with ever-improving phylogenetic hypotheses for the inter-relationships of modern birds founded on morphological characters. One key avifauna of this age, synthesised for the first time herein, is the Lower Eocene Fur Formation of Denmark. The Fur birds represent some of the best preserved (often in three dimensions and with soft tissues) known fossil records for major clades of modern birds. Clear phylogenetic assessment of these fossils will prove critical for future calibration of the neornithine evolutionary timescale. Some early diverging clades were clearly present in the Paleocene as evidenced directly by new fossil material alongside the phylogenetically constrained Lower Eocene taxa. A later Oligocene radiation of clades other than Passeriformes is not supported by available fossil data.

The European view of hospital undernutrition.

Disease-related undernutrition is significant in European hospitals but is seldom treated or prevented. In 1999, the Council of Europe decided to collect information regarding nutrition programs in hospitals, and for this purpose, a network consisting of national experts from 12 of the Partial Agreement member states was established. The aim was to review the current practices in Europe regarding hospital food provision, to highlight deficiencies, and to issue recommendations to improve the nutritional care and support of hospitalized patients. Five major common problems were identified: 1) lack of clearly defined responsibilities, 2) lack of sufficient education, 3) lack of influence and knowledge of the patients, 4) lack of cooperation between different staff groups, and 5) lack of involvement from the hospital management. To solve the problems highlighted, a combined timely and concerted effort is required from national authorities and hospital staff, including managers, to ensure appropriate nutritional care and support.

Alterations in plant growth and in root hormone levels of lodgepole pines inoculated with rhizobacteria.

The presence of other soil microorganisms might influence the ability of rhizobacterial inoculants to promote plant growth either by reducing contact between the inoculant and the plant root or by interfering with the mechanism(s) involved in rhizobacterially mediated growth promotion. We conducted the following experiments to determine whether reductions in the extent of growth promotion of lodgepole pine mediated by Paenibacillus polymyxa occur in the presence of a forest soil isolate (Pseudomonas fluorescens M20) and whether changes in plant growth promotion mediated by P. polymyxa (i) are related to changes in P. polymyxa density in the rhizosphere or (ii) result from alterations in root hormone levels. The extent of plant growth, P. polymyxa rhizosphere density, and root hormone concentrations were determined for lodgepole pine treated with (i) a single growth-promoting rhizobacterial strain (P. polymyxa L6 or Pw-2) or (ii) a combination of bacteria: strain L6 + strain M20 or strain Pw-2 + strain M20. There was no difference in the growth of pines inoculated with strain L6 and those inoculated with strain L6 + strain M20. However, seedlings inoculated with strain Pw-2 had more lateral roots and greater root mass at 12 weeks after inoculation than plants inoculated with strain Pw-2 + strain M20. The extent of growth promotion mediated by P. polymyxa L6 and Pw-2 in each treatment was not correlated to the average population density of each strain in the rhizosphere. Bacterial species-specific effects were observed in root hormone levels: indole-3-acetic acid concentration was elevated in roots inoculated with P. polymyxa L6 or Pw-2, while dihydrozeatin riboside concentration was elevated in roots inoculated with P. fluorescens M20.

Performance of a pyrethroid-resistant strain of the predator mite Typhlodromus pyri (Acari: Phytoseiidae) under different insecticide regimes.

An organophosphate pyrethroid-resistant strain of Typhlodromus pyri Scheuten imported from New Zealand was reared on potted apple trees in an outdoor insectary. From 1988 to 1995, the population was selected one to three times per year with a dilute solution (1.7 ppm) of the pyrethroid cypermethrin. Petri dish bioassays with cypermethrin in 1995 indicated that the insectary-reared T. pyri had an LC50 of 81 ppm versus 0.006 ppm for native T. pyri taken from a research orchard. The bioassays suggested that recommended orchard rates of cypermethrin would cause heavy mortality in native populations of T. pyri but only moderate losses in the imported New Zealand strain. Bioassays in 1996 with the organophosphate insecticide dimethoate indicated both New Zealand and native T. pyri were susceptible and that recommended orchard rates of dimethoate likely would cause high mortality of T. pyri in apple orchards. These findings from bioassays were supported by data from orchard trials. In June and July 1993, insectary-reared New Zealand T. pyri were placed on five apple trees in each of eight 38-tree plots in the research orchard. In late August 1994, New Zealand T. pyri from orchard trees that had been sprayed twice by airblast sprayer with the full recommended rate of 50 g (AI)/ha (83 ppm) cypermethrin were placed on the other 33 trees in each of six plots. In the summers of 1994-1996, plots were treated with one of the following insecticide regimes: (1) conventional integrated pest management (IPM) (registered neurotoxic insecticides considered harmless or slightly toxic to T. pyri); (2) advanced IPM (use of newer, more selective insecticides); (3) pyrethroid (at least one full-rate application of cypermethrin); (4) dimethoate; and (5) dimethoate plus pyrethroid. Densities of European red mite, Panonychus ulmi (Koch), were highest in all plots treated with dimethoate and in pyrethroid plots not yet inoculated with New Zealand T. pyri. Densities of apple rust mite, Aculus schlechtendali (Nalepa), and of the stigmaeid predator Zetzellia mali (Ewing) were highest in plots treated with dimethoate and were nearly absent in the IPM plots. Densities of T. pyri were high enough for effective biocontrol in the IPM plots and in the pyrethroid plots 1-2 yr after release of the New Zealand strain, provided pyrethroid was applied just before the resistant strain was released in the orchard. A recurring theme of this study was the generally negative association between densities of phytophagous mites and those of T. pyri, suggesting the ability of this predator to suppress their prey. In contrast, the positive association between phytophagous mites and Z. mali suggests the inability of this predator to regulate their prey at least under the conditions of this study.

Identification and analysis of homoeologous segments of the genomes of rice and Arabidopsis thaliana.

Using contiguous genomic DNA sequences of Arabidopsis thaliana, we were able to identify a region of conserved structure in the genome of rice. The conserved, and presumptive homoeologous segments, are 194 kb and 219-300 kb in size in Arabidopsis and rice, respectively. They contain five homologous genes, distinguished in order by a single inversion. These represent the first homoeologous segments identified in the genomes of a dicot and a monocot, demonstrating that fine-scale conservation of genome structure exists and is detectable across this major divide in the angiosperms. The conserved framework of genes identified is interspersed with non-conserved genes, indicating that mechanisms beyond segmental inversions and translocations need to be invoked to fully explain plant genome evolution, and that the benefits of comparative genomics over such large taxonomic distances may be limited.

BAC representation of two low-copy regions of the genome of Arabidopsis thaliana.

Two regions of Arabidopsis chromosome 4, totalling 4.7 Mb, were assayed for representation in the TAMU and IGF BAC libraries. A directed approach to BAC identification was developed. Gel-purified DNA samples of YACs selected from the YAC-based physical map of chromosome 4 were used to probe high-density colony arrays of the BAC libraries. Strategies were developed that allowed the efficient construction of restriction maps and BAC contigs. Four hundred and sixty-four BACs were mapped, assembled into two complete contigs and used to analyse genomic representation. These BACs provided a mean of 9.4-fold redundant coverage, with a range of 2- to 22-fold. The representation provided by the two libraries showed almost coincident peaks and troughs, with a periodicity of approximately 200 kb. These results demonstrate that, provided both TAMU and IGF libraries are used in their entirety, BACs should provide an excellent resource for both physical mapping and sequencing of the Arabidopsis genome.

Analysis of 1.9 Mb of contiguous sequence from chromosome 4 of Arabidopsis thaliana.

The plant Arabidopsis thaliana (Arabidopsis) has become an important model species for the study of many aspects of plant biology. The relatively small size of the nuclear genome and the availability of extensive physical maps of the five chromosomes provide a feasible basis for initiating sequencing of the five chromosomes. The YAC (yeast artificial chromosome)-based physical map of chromosome 4 was used to construct a sequence-ready map of cosmid and BAC (bacterial artificial chromosome) clones covering a 1.9-megabase (Mb) contiguous region, and the sequence of this region is reported here. Analysis of the sequence revealed an average gene density of one gene every 4.8 kilobases (kb), and 54% of the predicted genes had significant similarity to known genes. Other interesting features were found, such as the sequence of a disease-resistance gene locus, the distribution of retroelements, the frequent occurrence of clustered gene families, and the sequence of several classes of genes not previously encountered in plants.