Diet and the risk of head and neck cancer: a pooled analysis in the INHANCE consortium.

We investigated the association between diet and head and neck cancer (HNC) risk using data from the International Head and Neck Cancer Epidemiology (INHANCE) consortium. The INHANCE pooled data included 22 case-control studies with 14,520 cases and 22,737 controls. Center-specific quartiles among the controls were used for food groups, and frequencies per week were used for single food items. A dietary pattern score combining high fruit and vegetable intake and low red meat intake was created. Odds ratios (OR) and 95% confidence intervals (CI) for the dietary items on the risk of HNC were estimated with a two-stage random-effects logistic regression model. An inverse association was observed for higher-frequency intake of fruit (4th vs. 1st quartile OR = 0.52, 95% CI = 0.43-0.62, p (trend) < 0.01) and vegetables (OR = 0.66, 95% CI = 0.49-0.90, p (trend) = 0.01). Intake of red meat (OR = 1.40, 95% CI = 1.13-1.74, p p (trend) < 0.01) was positively associated with HNC risk. Higher dietary pattern scores, reflecting high fruit/vegetable and low red meat intake, were associated with reduced HNC risk (per score increment OR = 0.90, 95% CI = 0.84-0.97).

Plants and tortoises: mutations in the Arabidopsis jasmonate pathway increase feeding in a vertebrate herbivore.

Photosynthetic tissues, the major food source of many invertebrates and vertebrates, are well defended. Many defence traits in leaves are controlled via the jasmonate signalling pathway in which jasmonate acts as a hormone by binding to a receptor to activate responses that lead to increased resistance to invertebrate folivores. We predicted that mutations in jasmonate synthesis might also increase the vulnerability of leaves to vertebrate folivores and tested this hypothesis using the Eastern Hermann's tortoise (Eurotestudo boettgeri) and an Arabidopsis thaliana (Brassicaceae) allene oxide synthase (aos) mutant unable to synthesize jasmonate. Tortoises preferred the aos mutant over the wild type (WT). Based on these results, we then investigated the effect of mutating jasmonate perception using a segregating population of the recessive A. thaliana jasmonate receptor mutant coronatine insensitive1-1 (coi1-1). Genotyping of these plants after tortoise feeding revealed that the homozygous coi1-1 receptor mutant was consumed more readily than the heterozygous mutant or the WT. Therefore, the plant's ability to synthesize or perceive jasmonate reduces feeding by a vertebrate herbivore. We also tested whether or not tortoise feeding behaviour was influenced by glucosinolates, the principal defence chemicals in Arabidopsis leaves with known roles in defence against many generalist insects. However, in contrast to what has been observed with such insects, leaves in which the levels of these compounds were reduced genetically were consumed at a similar rate to those of the WT.

How siblings adjust sib-sib communication and begging signals to each other

Parents allocate food resources to their offspring in proportion to the intensity of begging behaviour. Begging encompasses several activities including vocalizations that should honestly signal need and jostling for the position in the nest where parents predictably deliver food items. Although siblings are known to adjust begging level to each other, the underlying mechanism remains unknown. We examined this issue in experimental two-chick broods of the barn owl, Tyto alba, a species in which siblings communicate vocally with each other in the prolonged absence of parents. The function of sib-sib vocal communication, so-called sibling negotiation, is to resolve conflicts over which individual will have priority of access to the next delivered indivisible food item. We found that when a nestling produced longer negotiation calls and stood closer to the nestbox entrance in the absence of parents, its sibling vocally negotiated at a lower rate. Additionally, when an individual produced more negotiation calls in the absence of parents, its sibling begged less intensely at the parent's return, with begging being the key factor that determined which nestling obtained a food item. We conclude that position in the nest and the duration of negotiation calls produced in the absence of parents influence the rate of producing negotiation calls, which in turn influences the rate at which siblings beg for food from their parents. Adjusting begging behaviour could therefore depend on complex sib-sib interactions taking place in the prolonged absence of parents.

Age-Related Tooth Wear Differs between Forest and Savanna Primates

Tooth wear in primates is caused by aging and ecological factors. However, comparative data that would allow us to delineate the contribution of each of these factors are lacking. Here, we contrast age-dependent molar tooth wear by scoring percent of dentine exposure (PDE) in two wild African primate populations from Gabonese forest and Kenyan savanna habitats. We found that forest-dwelling mandrills exhibited significantly higher PDE with age than savanna yellow baboons. Mandrills mainly feed on large tough food items, such as hard-shell fruits, and inhabit an ecosystem with a high presence of mineral quartz. By contrast, baboons consume large amounts of exogenous grit that adheres to underground storage organs but the proportion of quartz in the soils where baboons live is low. Our results support the hypothesis that not only age but also physical food properties and soil composition, particularly quartz richness, are factors that significantly impact tooth wear. We further propose that the accelerated dental wear in mandrills resulting in flatter molars with old age may represent an adaptation to process hard food items present in their environment.

Ecological interactions between zooplankton and photosynthetic bacteria in Crawford Lake, Ontario

The present study was carried out to test the hypothesis that photosynthetic bacteria contribute a large portion of the food of filter feeding zooplankton populations in Crawford Lake, Ontario. The temporal and spatial variations of both groups of organisms are strongly dependent on one another. 14 By using C-Iabelled photosynthetic bacteria. the ingestion and clearance rates of Daphnia pulex, ~. rosea, and Keratella spp were estimated during summer and fall of 1982. These quantitative estimations of zooplankton ingestion and clearence rates on photosynthetic bacteria comprised an original addition to the literature. Photosynthetic bacteria comprised a substantial portion of the diet of all four dominant zooplankton species. The evidence for this is based on the ingestion and clearance rates of the dominant zooplankton species. Ingestion rates of D. pulex and D. rosea ranged 5 5 -1 -1 - -- 5 - -- 5 from 8.3X10 -1 to 14.6XlO -1 cells.ind. hr and 8.1X10 to 13.9X10 cells.ind. hr • Their clearance rates ranged from 0.400 to 1.000 -1 -1 -1 -1 ml.ind. hr. and 0.380 to 0.930 ml.ind. hr • The ingestion and clearance -1 -1 -1 -1 rates of Keratella spp were 600 cell.ind. hr and 0.40 ul.ind. hr respectively. Clearance rates were inversely proportional to the concentration of food cells and directly proportional to the body size of the animals. It is believed that despite the very short reg~neration times of photosynthetic bacteria (3-8 hours) their population densities were controlled in part by the feeding rates of the dominant zooplankton in Crawford Lake. By considering the regeneration times of photosynthetic bacteria and the population clearance rates of zooplankton, it was estimated that between 16 to 52% and 11 to 35% of the PHotosynthetic bacteria were' consumed· by Daphnia· pulex. and Q.. rosea per day. The temporal and spatial distribution of Daphnia pulex, !.. rosea, Keratella quadrata, K. coChlearis and photosynthetic bacteria in Crawford Lake were also investigated during the period of October, 1981 to December, 1982. The photosynthetic bacteria in the lake, constituted a major food source for only those zooplankton Which tolerate anaerobic conditions. Changes in temperature and food appeared to correlate with the seasonal changes in zooplankton density. All four dominant species of zooplankton were abundant at the lake's surface (O-4m) during winter and spring and moved downwards with the thermocline as summer stratification proceeded. Photosynthetic bacteria formed a 2 m thick layer at the chemocline. The position of this photosynthetic bacterial J-ayer changed seasonally. In the summer, the bacterial plate moved upwards and following fall mixing it moved downwards. A vertical shift of O.8m (14.5 to 15.3m) was recorded during the period of June to December. The upper limit of the photosynthetic bacteria in the water column was controlled by dissolved oxygen, and sulfide concentrations While their lower limit was controlled by light intensity. A maximum bacterio- 1 chlorophyll concentration of 81 mg Bchl.l was recorded on August 9, 1981. The seasonal distribution of photosynthetic bacteria was controlledinpart' by ·theg.-"z1ai'_.Q;~.zoopl. ank:tCm;-.Qther -ciactors associated with zooplankton grazing were oxygen and sulfide concentrations.

Différence dans la qualité de l’alimentation en relation au risque d’excès de poids chez des populations autochtones canadiennes

L‘obésité constitue un problème de santé publique au Canada, particulièrement chez les populations autochtones où les prévalences les plus élevées ont été rapportées. D’après les écrits recensés, plusieurs méthodes ont été essayées pour étudier la relation entre l’alimentation et l’obésité, mais les résultats sont inconstants. Le but de cette thèse est d’identifier, en termes quantitatif et qualitatif, les différences dans l’alimentation des obèses et non-obèses. Pour y parvenir, nous avons développé une nouvelle méthode à l’aide d’une banque de données portant sur les enfants Mohawk de Kahnawake afin d’identifier les différences dans les choix alimentaires. Cette même méthode a été ensuite appliquée à deux autres banques de données (celle des adultes cris de la Baie James et celle des autochtones de l’enquête ESCC 2.2). Globalement, les résultats n’ont pas montré de différences significatives dans l’alimentation des participants selon les catégories d’IMC en considérant les indicateurs reliés à la quantité et à la qualité de l’alimentation comme l’apport énergétique total, l’apport énergétique en provenance des lipides, les fibres alimentaires, la densité énergétique et la diversité alimentaire. Par contre, les résultats de la nouvelle méthode fondée sur la sélection des items alimentaires fréquemment consommés par au moins 10 % des participants ont révélé que les enfants de Kahnawake à risque d’excès de poids consommaient plus fréquemment de croustilles (p=0.001) et moins fréquemment de craquelins que les enfants avec excès de poids ou ceux ayant un poids normal (p=0.015). Ensuite, en prenant la catégorie de poids normal comme référence, le rapport de côte (Odds ratio : OR) d’être à risque d’excès de poids était de 2.16 (95 % IC : 1.14 - 4.09) fois plus élevé chez les enfants de Kahnawake qui consommaient plus fréquemment de croustilles comparativement aux non-consommateurs de croustilles, et ce, après ajustement pour l’âge. Par contre, le rapport de côte d’être à risque d’excès de poids diminuait de 79 % (OR = 0.21; 95 % IC : 0.06 – 0.72) chez les enfants consommateurs de craquelins comparativement à leurs homologues non-consommateurs. Après avoir corrigé les quantités pour l’âge, on note que les enfants avec excès de poids consommaient plus de frites que les enfants à risque d’excès de poids ou ceux ayant un poids normal (p = 0.027). Chez les femmes cries, les résultats de la nouvelle méthode ont montré que le colorant à café était associé à un risque élevé d’obésité (OR = 4.64, 95 % IC : 1.04 - 0.54); alors que le lait faible en matières grasses était associé à un moindre risque d’embonpoint (OR = 0.38, 95 % IC : 0.17 - 0.82), après ajustement pour l’âge. Quant aux hommes cris, le lait entier était associé à un moindre risque d’avoir de l’embonpoint (OR ajusté pour l’âge = 0.38, 95 % IC : 0.20 - 0.71) et, en termes de quantité corrigée pour l’âge, les hommes obèses buvaient plus de boissons sucrées aux fruits comparativement aux hommes de poids normal ou ceux ayant de l’embonpoint (p=0.015). Selon les résultats de cette méthode appliquée aux données de l’enquête ESCC 2.2, les garçons à risque d’excès de poids ou avec excès de poids consommaient moins fréquemment de pain blanc que ceux de poids normal (p=0.048). En termes de quantité toutefois, ils consommaient plus de pain blanc (p=0.040), utilisaient plus de farine de blé (p=0.006) et de levure (p=0.002). Après avoir ajusté les quantités consommées pour l’âge et l’indice d’activité physique, les femmes avec embonpoint ou obèses utilisaient plus de farine de blé (p< 0.001) que leurs homologues de poids normal. Chez les hommes, il n'y avait pas de différences ni dans les fréquences de consommation ni dans les quantités consommées. Concernant les filles, leurs apports alimentaires n'étaient pas valides (facteur d'activité de Goldberg < 1.2 dans la catégorie embonpoint / obèse). Les résultats de cette méthode innovatrice pourraient d’une part, permettre d’axer la sensibilisation sur des aliments particuliers en plus des recommandations générales du Guide Alimentaire Canadien. D’autre part, ils nous renvoient aux données biologiques de laboratoire afin d’identifier les composantes des items susceptibles de contribuer au développement de l’obésité.

Mealtime experiences of hospitalized older patients requiring a puree consistency diet

Le concept d’Hôpital Promoteur de Santé (HPS) a pris beaucoup d’importance depuis son élaboration vers la fin des années quatre-vingt. Dans le contexte de la dernière réforme, le réseau montréalais des HPS et CSSS a été créé. Le Centre Universitaire de Santé McGill (CUSM) fait partie de ce réseau depuis 2007. Cette étude vise la création d’un milieu hospitalier promoteur de la santé pour les patients et s’adresse à l’expérience d’un repas pour les personnes âgées nécessitant une diète purée. Une étude de cas qualitative a été utilisée pour explorer la perception de patients vis-à-vis les aspects relatifs à leur cabaret, l’assistance qu’ils recevaient et le contexte social de leur repas. Les impressions des professionnels de la santé quant à l’expérience des patients ont aussi été obtenues. Les résultats indiquent que l’identification difficile des aliments en purée, la saveur, l’apparence et la variété sont tous des éléments qui affectent négativement leur expérience repas. Des sentiments d’impuissance ont aussi été rapportés par les patients et les professionnels de la santé. Le contexte social du repas a été souligné comme étant un aspect à cibler pour améliorer l’expérience des patients. Un programme utilisant des purées formées pourrait contrecarrer les effets négatifs de la prescription d’une diète purée. Des changements dans les pratiques infirmières, à savoir la création d’une ambiance sociale agréable au moment des repas, semble être une option peu couteuse qui pourrait améliorer l’expérience repas des patients et diminuer les sentiments d’impuissance relevés par les professionnels de la santé à l’égard de cet aspect de soin.

Mercure, arsenic et sélénium au Burkina Faso : bioaccumulation, transfert trophique dans les systèmes aquatiques et évaluation de bioaccessibilité chez les humains

L’extraction aurifère est l’une des activités humaines qui a fortement accru l’émission de contaminants métalliques dans l’environnement. Le mercure (Hg), l’arsenic (As) et le sélénium (Se) sont 3 polluants métalliques de grande toxicité environnementale. En milieu aquatique, ils peuvent subir des transformations menant à des composés capables de bioaccumulation et de bioamplification. Il peut en résulter des concentrations 106 fois celle mesurée dans l’eau chez les poissons et les organismes situés en haut des chaînes alimentaires posant de ce fait de graves menaces pour la santé de ces organismes ainsi que leurs consommateurs y compris les humains. Cette étude a évalué les teneurs en Hg, As et Se dans les milieux aquatiques au Burkina Faso, une région d’Afrique sub-saharienne soumise à une exploitation minière intensive. Le risque potentiel pour les organismes aquatiques et les humains a été évalué en considérant les effets des interactions antagonistes Se/Hg et As/Se. La bioaccumulation et le transfert du Hg et du Se dans les réseaux trophiques sont également décrits. L’exposition au Hg de poissons par les humains a été également évalué au laboratoire par mesure de la bioaccessibilité comme équivalent de la biodisponibilité par simulation de la digestion humaine. En général, les milieux aquatiques étudiés étaient peu affectés par ces 3 métal(loïd)s bien que certaines espèces de poisson issus des réservoirs les plus profonds indiquent des teneurs de Hg au dessus de 500 ngHg/g (poids frais) recommandé par l’OMS. Ces niveaux sont susceptibles de présenter des risques toxicologiques pour les poissons et pour leurs consommateurs. En considérant l’antagonisme Se/Hg, 99 % des échantillons de poisson seraient moins exposés à la toxicité du Hg dû à la présence simultanée du sélénium dans le milieu et pourraient être consommés sans risque. Cependant, les effets potentiels de l’antagonisme As/Se pourraient réduire les effets bénéfiques du Se et ramener cette proportion à 83 %. L’application des mesures de signatures en isotopes stables d’azote (δ15N) et de carbone (δ13C) des organismes aquatiques a permis le traçage des voies de transfert du Hg et du Se dans les réseaux trophiques. On y observe des chaînes trophiques très courtes (3 - 4 niveaux trophiques) et des poissons majoritairement benthiques. L’approche isotopique n’a cependant pas permis de détecter les variations saisonnières des niveaux de contamination en Hg des poissons. L’exploration des contenus stomacaux des poissons a permis de mieux expliquer la baisse des concentrations en Hg et Se observées chez certains poissons au cours de la saison sèche en lien avec la variation de la composition des proies que l’analyse isotopique n’a pas cerné. L’étude suggère que l’analyse de contenus stomacaux ainsi que l’étude de la dynamique des communautés d’invertébrés couplées à celle des métaux pourraient améliorer la compréhension du fonctionnement des écosystèmes étudiés. Enfin, l’évaluation expérimentale de l’exposition au Hg indique que les modes de traitement avant consommation ainsi que l’usage de composés alimentaires tels le thé, le café lors de repas de poisson par certaines communautés humaines ont un impact sur la bioaccessibilité du Hg de poisson. Ces résultats, sous réserve de validation par des modèles animaux, suggèrent la prise en compte des habitudes alimentaires des communautés dans l’élaboration adéquat des avis de consommation de poisson.

Studies On Pobtunid Crabs [Crustacea Decapoda Brachyura)

True crabs are the most fascinating group of organisms among the decapod crustaceans. Great importance is attached at present to the increased exploitation of these animals and therefore there is great scope for further development of their fishery. They have a broad and hard carapace, massive chelate legs, bent abdomen and exhibit high degree of adaptation to the environment. They show pelagic, benthic, intertidal, burrowing and terrestrial modes of life. Their commensal association with other invertebrates, their breeding behaviour and life history are of great interest to biologists. More than six hundred species of crabs are known to occur in Indian waters and among them about eight species form a regular fishery along the entire stretch of peninsular India (Rao §§_al., 1973) round the year. Crab fishery in India is fast developing and there is vast scope for them as there are many more potential species. Among the various crustacean diets, crabs are celebrated for deliciousness and for nutritional richness. In recent days, crab food items have become more popular and gained global reception. These resources can also be augmented further by culturing them in ponds in the future. Information on biology and ecology of constituent species go a long way not only in effective exploitation and regulation of the respective fishery resources but also helps in evolving a suitable gear for their capture. Information collected on the national level in various aspects as reproduction, growth rate, larval development, parasites, diseases, nutritive values etc. will be of help in evolving a national policy for the effective utilisation and conservation of this resource. They also provide the baseline information for undertaking any purposeful and meaningful culture activities. Information on the various aspects mentioned above is very much restricted in true crabs and hence the present study

Bryozoan populations reflect nutrient enrichment and productivity gradients in rivers

1. The hypothesis that nutrient enrichment will affect bryozoan abundance was tested using two complementary investigations; a field-based method determining bryozoan abundance in 20 rivers of different nutrient concentrations by deploying statoblast (dormant propagule) traps and an experimental laboratory microcosm study measuring bryozoan growth and mortality. These two methods confirmed independently that increased nutrient concentrations in water promote increases in the biomass of freshwater bryozoans. 2. Statoblasts of the genus Plumatella were recorded in all rivers, regardless of nutrient concentrations, demonstrating that freshwater bryozoans are widespread. Concentrations of Plumatella statoblasts were high in rivers with high nutrient concentrations relative to those with low to moderate nutrient concentrations. Regression analyses indicated that phosphorus concentrations, in particular, significantly influenced statoblast concentrations. 3. Concentrations of Lophopus crystallinus statoblasts were also higher in sites characterised by high nutrient concentrations. Logistic regression analysis revealed that the presence of L. crystallinus statoblasts was significantly associated with decreasing altitude and increasing phosphorus concentrations. This apparently rare species was found in nine rivers (out of 20), seven of which were new sites for L. crystallinus. 4. Growth rates of Fredericella sultana in laboratory microcosms increased with increasing nutrient concentration and high mortality rates were associated with low nutrient concentrations. 5. Our results indicate that bryozoans respond to increasing nutrient concentrations by increased growth, resulting in higher biomasses in enriched waters. We also found that an important component of bryozoan diets can derive from food items lacking chlorophyll a. Finally, bryozoans may be used as independent proxies for inferring trophic conditions, a feature that may be especially valuable in reconstructing historical environments by assessing the abundance of statoblasts in sediment cores.

Assessment of the impact of government animal welfare policy on farm animal welfare in the UK

The paper presents the method and findings of a Delphi expert survey to assess the impact of UK government farm animal welfare policy, form assurance schemes and major food retailer specifications on the welfare of animals on forms. Two case-study livestock production systems are considered, dairy and cage egg production. The method identifies how well the various standards perform in terms of their effects on a number of key farm animal welfare variables, and provides estimates of the impact of the three types of standard on the welfare of animals on forms, taking account of producer compliance. The study highlights that there remains considerable scope for government policy, together with form assurance schemes, to improve the welfare of form animals by introducing standards that address key factors affecting animal welfare and by increasing compliance of livestock producers. There is a need for more comprehensive, regular and random surveys of on-farm welfare to monitor compliance with welfare standards (legislation and welfare codes) and the welfare of farm animals over time, and a need to collect farm data on the costs of compliance with standards.

Consumer attitudes towards and willingness to pay for pesticide residue limit compliant 'safe' vegetables in Northeast Thailand

Pesticide residue in vegetables is a major food safety issue in Thailand. A range of vegetable products (organic/pesticide-free/ hydroponic) has emerged in Thai markets that guarantee compliance with maximum residue limits. The Government of Thailand is eager to extend the benefits of this suite of alternative vegetables to the entire population, particularly the semi-urban/rural segments that are often bypassed by such speciality products. However, little information is available to guide such an effort, particularly with regard to up-country consumer attitudes, shopping and consumption habits and willingness to pay premiums for such produce. This research aims to fill this gap in knowledge. It reports the results of a survey of vegetable consumption and shopping habits and attitudes of 608 consumers in northeast Thailand. Willingness to pay premiums for pesticide residue limit compliant vegetables is also assessed by using a contingent valuation method, and determinants of willingness to pay are examined using an ordered probit empirical model. Results indicate that, given adequate awareness of relative risks, even up-country consumers are willing to pay market premium levels for these products, and that inadequate availability, rather than lack of demand is the constraining factor. Willingness to pay is found to increase with income, age and supermarket sourcing of vegetables. We also discuss the challenge of improving availability at mainstream outlets.

Bryozoan populations reflect nutrient enrichment and productivity gradients in rivers

P>1. The hypothesis that nutrient enrichment will affect bryozoan abundance was tested using two complementary investigations; a field-based method determining bryozoan abundance in 20 rivers of different nutrient concentrations by deploying statoblast (dormant propagule) traps and an experimental laboratory microcosm study measuring bryozoan growth and mortality. These two methods confirmed independently that increased nutrient concentrations in water promote increases in the biomass of freshwater bryozoans. 2. Statoblasts of the genus Plumatella were recorded in all rivers, regardless of nutrient concentrations, demonstrating that freshwater bryozoans are widespread. Concentrations of Plumatella statoblasts were high in rivers with high nutrient concentrations relative to those with low to moderate nutrient concentrations. Regression analyses indicated that phosphorus concentrations, in particular, significantly influenced statoblast concentrations. 3. Concentrations of Lophopus crystallinus statoblasts were also higher in sites characterised by high nutrient concentrations. Logistic regression analysis revealed that the presence of L. crystallinus statoblasts was significantly associated with decreasing altitude and increasing phosphorus concentrations. This apparently rare species was found in nine rivers (out of 20), seven of which were new sites for L. crystallinus. 4. Growth rates of Fredericella sultana in laboratory microcosms increased with increasing nutrient concentration and high mortality rates were associated with low nutrient concentrations. 5. Our results indicate that bryozoans respond to increasing nutrient concentrations by increased growth, resulting in higher biomasses in enriched waters. We also found that an important component of bryozoan diets can derive from food items lacking chlorophyll a. Finally, bryozoans may be used as independent proxies for inferring trophic conditions, a feature that may be especially valuable in reconstructing historical environments by assessing the abundance of statoblasts in sediment cores.

Environmental variation at the onset of independent foraging affects full-grown body mass in the red fox

The period following the withdrawal of parental care has been highlighted as a key developmental period for juveniles. One reason for this is that juveniles cannot forage as competently as adults, potentially placing them at greater risk from environmentally-induced changes in food availability. However, no study has examined this topic. Using a long-term dataset on red foxes (Vulpes vulpes), we examined (i) dietary changes that occurred in the one-month period following the attainment of nutritional independence, (ii) diet composition in relation to climatic variation, and (iii) the effect of climatic variation on subsequent full-grown mass. Diet at nutritional independence contained increased quantities of easy-to-catch food items (earthworms and insects) when compared with pre-independence. Interannual variation in the volume of rainfall at nutritional independence was positively correlated to the proportion of earthworms in cub diet. Pre-independence cub mass and rainfall immediately following nutritional independence explained a significant proportion of variance in full-grown mass, with environmental variation affecting full-grown mass of the entire cohorts. Thus, weather-mediated availability of easy-to-catch food items at a key developmental stage has lifelong implications for the development of juvenile foxes by affecting full-grown mass, which in turn appears to be an important component of individual reproductive potential.

Domestication of plants in the americas: Insights from mendelian and molecular genetics

Background Plant domestication occurred independently in four different regions of the Americas. In general, different species were domesticated in each area, though a few species were domesticated independently in more than one area. The changes resulting from human selection conform to the familiar domestication syndrome, though different traits making up this syndrome, for example loss of dispersal, are achieved by different routes in crops belonging to different families. Genetic and Molecular Analyses of Domestication Understanding of the genetic control of elements of the domestication syndrome is improving as a result of the development of saturated linkage maps for major crops, identification and mapping of quantitative trait loci, cloning and sequencing of genes or parts of genes, and discoveries of widespread orthologies in genes and linkage groups within and between families. As the modes of action of the genes involved in domestication and the metabolic pathways leading to particular phenotypes become better understood, it should be possible to determine whether similar phenotypes have similar underlying genetic controls, or whether human selection in genetically related but independently domesticated taxa has fixed different mutants with similar phenotypic effects. Conclusions Such studies will permit more critical analysis of possible examples of multiple domestications and of the origin(s) and spread of distinctive variants within crops. They also offer the possibility of improving existing crops, not only major food staples but also minor crops that are potential export crops for developing countries or alternative crops for marginal areas.