Rabbit and fox introductions in tierra del fuego: history and assessment of the attempts at biological control of the rabbit infestation

Four European rabbits Oryctolagus cuniculus were introduced in the Chilean side of Tierra del Fuego island in 1936. At the height of the rabbit infestation (1953) they numbered about 30 million. Twenty-four foxes Dusicyon griseus were released in Tierra del Fuego in 1951, three years before the myxoma virus decimated the rabbit populations. We document the history of the introductions of both rabbits and foxes in Tierra del Fuego, and evaluate the role of foxes as biological-control agents for the rabbits.     

Prestorage heat treatment to maintain nutritive and functional properties during postharvest cold storage of pomegranate

Heat treatments have been used to extend storability of several fruits, although no information is available about their effects on nutritive and functional properties in pomegranates, which was the objective of this research. Thus, pomegranate fruits were heat treated (dips at 45 degrees C for 4 min) and stored at 2 degrees C for 90 days. Every 15 days, samples were taken and further stored 2 days at 20 degrees C for shelf life study. Arils from heat-treated pomegranates exhibited higher total antioxidant activity than controls, which was correlated primarily to the high levels of total phenolics and to lesser extent to ascorbic acid and anthocyanin contents. Additionally, the levels of sugars (glucose and fructose) and organic acids (malic, citric, and oxalic acids) remained also at higher concentrations in arils from treated fruits. With this simple and non-contaminant technology, the functional and nutritive properties, after long periods of storage, could then be even greater than in recently harvested fruits, thus providing a high content in health-beneficial compounds to consumers after the intake of these fruits.     

Response of water and nutrient fluxes to improvement fellings in a tropical montane forest in Ecuador

Management of natural forests might be one option to reduce the high deforestation rate in Ecuador. We therefore evaluated the response of water and nutrient cycles in a natural tropical montane forest to improvement fellings with the aim of favoring economically valuable target trees which will later be harvested with additional ecosystem impacts not considered here.     

Paired-end mapping reveals extensive structural variation in the human genome

Structural variation of the genome involves kilobase- to megabase-sized deletions, duplications, insertions, inversions, and complex combinations of rearrangements. We introduce high-throughput and massive paired-end mapping (PEM), a large-scale genome-sequencing method to identify structural variants (SVs) approximately 3 kilobases (kb) or larger that combines the rescue and capture of paired ends of 3-kb fragments, massive 454 sequencing, and a computational approach to map DNA reads onto a reference genome. PEM was used to map SVs in an African and in a putatively European individual and identified shared and divergent SVs relative to the reference genome. Overall, we fine-mapped more than 1000 SVs and documented that the number of SVs among humans is much larger than initially hypothesized; many of the SVs potentially affect gene function. The breakpoint junction sequences of more than 200 SVs were determined with a novel pooling strategy and computational analysis. Our analysis provided insights into the mechanisms of SV formation in humans.     

Another gene affecting fruit and stem color in squash, Cucurbita pepo

Of the 13 genes described as affecting fruit color in Cucurbita pepo, one, D (Dark stem), also markedly affects stem color. The D allele confers dark stems and dark intermediate-age fruits, is dominant to the d allele for light stems and fruits, and epistatic to two recessive genes conferring light fruit coloration, l-1 and l-2. However, a gene for light fruit coloration, W (Weak fruit color), is epistatic to D in the fruits. We observed variation for stem color in a scallop squash cultivar having light-colored fruits, some plants having dark stems and others light stems. Two true-breeding inbreds of this cultivar, one having dark stems and the other light stems, were developed and, when these inbreds were crossed, the progeny had light stems. In order to elucidate the genetic basis of the dominant light-stem characteristic, these two inbreds were crossed with two near-isogenic tester lines, one of genotype D/D l-1/l-1 l-2/l-2 and the other of genotype d/d l-1/l-1 l-2/l-2. Also, the dominant light stem and light fruit color were introgressed into a third near-isogenic line of genotype D/D l-1/l-1 l-2/l-2, resulting in two new near-isogenic lines, and these lines were then intercrossed. The results showed that the variation in stem color of the scallop squash cultivar derives from segregation of alleles at the W locus, with a newly designated top-dominant allele, W ^S , conferring both, light stems and light fruits. This allele may be genetically unstable and sub-vital.