History and structure of the closed pedigreed population of Icelandic Sheepdogs

<p>Abstract</p> <p>Background</p> <p>Dog breeds lose genetic diversity because of high selection pressure. Breeding policies aim to minimize kinship and therefore maintain genetic diversity. However, policies like mean kinship and optimal contributions, might be impractical. Cluster analysis of kinship can elucidate the population structure, since this method divides the population in clusters of related individuals. Kinship-based analyses have been carried out on the entire Icelandic Sheepdog population, a sheep-herding breed.</p> <p>Results</p> <p>Analyses showed that despite increasing population size and deliberately transferring dogs, considerable genetic diversity has been lost. When cluster analysis was based on kinships calculated seven generation backwards, as performed in previous studies, results differ markedly from those based on calculations going back to the founder-population, and thus invalidate recommendations based on previous research. When calculated back to the founder-population, kinship-based clustering reveals the distribution of genetic diversity, similarly to strategies using mean kinship.</p> <p>Conclusion</p> <p>Although the base population consisted of 36 Icelandic Sheepdog founders, the current diversity is equivalent to that of only 2.2 equally contributing founders with no loss of founder alleles in descendants. The maximum attainable diversity is 4.7, unlikely achievable in a non-supervised breeding population like the Icelandic Sheepdog. Cluster analysis of kinship coefficients can provide a supporting tool to assess the distribution of available genetic diversity for captive population management.</p

Mapping carcass and meat quality QTL on Sus Scrofa chromosome 2 in commercial finishing pigs

Quantitative trait loci (QTL) affecting carcass and meat quality located on SSC2 were identified using variance component methods. A large number of traits involved in meat and carcass quality was detected in a commercial crossbred population: 1855 pigs sired by 17 boars from a synthetic line, which where homozygous (A/A) for IGF2. Using combined linkage and linkage disequilibrium mapping (LDLA), several QTL significantly affecting loin muscle mass, ham weight and ham muscles (outer ham and knuckle ham) and meat quality traits, such as Minolta-L* and -b*, ultimate pH and Japanese colour score were detected. These results agreed well with previous QTL-studies involving SSC2. Since our study is carried out on crossbreds, different QTL may be segregating in the parental lines. To address this question, we compared models with a single QTL-variance component with models allowing for separate sire and dam QTL-variance components. The same QTL were identified using a single QTL variance component model compared to a model allowing for separate variances with minor differences with respect to QTL location. However, the variance component method made it possible to detect QTL segregating in the paternal line (e.g. HAMB), the maternal lines (e.g. Ham) or in both (e.g. pHu). Combining association and linkage information among haplotypes improved slightly the significance of the QTL compared to an analysis using linkage information only

Estimating interregional economic impacts: an evaluation of nonsurvey, semisurvey, and full-survey methods

Literature shows that nonsurvey input-output tables tend to produce regional multipliers with systematic upward biases. This paper explores the related, relatively uncharted territory of nonsurvey versus survey impact studies by means of a series of simulations. The base case is provided by a very detailed five region survey of both the forward and the-backward impacts of the energy-distribution sector in the four northern provinces of. the Netherlands. To deal adequately with the two-sided dependence between a firm or sector and a region, as opposed to using the traditional (gross) multipliers, we argue in favor of using a new multiplier concept: the net multiplier. Next, from examining alternative impact study methods ranging from quick and dirty, via semiextensive, to full-survey methods, we conclude that using even aggregate, first-order impact information is more important than using a very detailed survey-based input-output model

Erstellung einer Input-Output-Tabelle für Mecklenburg-Vorpommern

Regionale Input-Output-Tabelle, Nonsurvey-Methode, Cross-Hauling, C67, C82, R15, Regional input-output table, Nonsurvey method, Cross-hauling,

A method for constructing commodity by industry flow matrices

This paper presents theory and methods used to construct an interregional commodity by industry flow matrix for the United States. The interregional flow matrix method involves the construction of single-state (and DC) social accounting matrices (SAMs) using data derived from IMPLAN. Once complete, the interregional flows connecting states are estimated using a method based on the commodity flow survey data published by the Bureau of Transportation Statistics. The estimated interregional SAM is then adjusted to insure the integrity of intra-regional and system-wide accounts. The procedures have been designed with ease of replicability as a goal so that updates and extensions of the database can be generated efficiently and at low cost as new data are released. The resulting US interregional framework describes flows within and among the 51 regions. The method is flexible and will provide a valuable database for a broad range of analyses on regions, interregional relationships, and policy