Major inconsistencies of inferred population genetic structure estimated in a large set of domestic horse breeds using microsatellites

STRUCTURE remains the most applied software aimed at recovering the true, but unknown, population structure from microsatellite or other genetic markers. About 30% of structure-based studies could not be reproduced (Molecular Ecology, 21, 2012, 4925). Here we use a large set of data from 2,323 horses from 93 domestic breeds plus the Przewalski horse, typed at 15 microsatellites, to evaluate how program settings impact the estimation of the optimal number of population clusters Kopt that best describe the observed data. Domestic horses are suited as a test case as there is extensive background knowledge on the history of many breeds and extensive phylogenetic analyses. Different methods based on different genetic assumptions and statistical procedures (dapc, flock, PCoA, and structure with different run scenarios) all revealed general, broad-scale breed relationships that largely reflect known breed histories but diverged how they characterized small-scale patterns. structure failed to consistently identify Kopt using the most widespread approach, the ΔK method, despite very large numbers of MCMC iterations (3,000,000) and replicates (100). The interpretation of breed structure over increasing numbers of K, without assuming a Kopt, was consistent with known breed histories. The over-reliance on Kopt should be replaced by a qualitative description of clustering over increasing K, which is scientifically more honest and has the advantage of being much faster and less computer intensive as lower numbers of MCMC iterations and repetitions suffice for stable results. Very large data sets are highly challenging for cluster analyses, especially when populations with complex genetic histories are investigated.info:eu-repo/semantics/publishedVersio

European domestic horses originated in two holocene refugia

The role of European wild horses in horse domestication is poorly understood. While the fossil record for wild horses in Europe prior to horse domestication is scarce, there have been suggestions that wild populations from various European regions might have contributed to the gene pool of domestic horses. To distinguish between regions where domestic populations are mainly descended from local wild stock and those where horses were largely imported, we investigated patterns of genetic diversity in 24 European horse breeds typed at 12 microsatellite loci. The distribution of high levels of genetic diversity in Europe coincides with the distribution of predominantly open landscapes prior to domestication, as suggested by simulation-based vegetation reconstructions, with breeds from Iberia and the Caspian Sea region having significantly higher genetic diversity than breeds from central Europe and the UK, which were largely forested at the time the first domestic horses appear there. Our results suggest that not only the Eastern steppes, but also the Iberian Peninsula provided refugia for wild horses in the Holocene, and that the genetic contribution of these wild populations to local domestic stock may have been considerable. In contrast, the consistently low levels of diversity in central Europe and the UK suggest that domestic horses in these regions largely derive from horses that were imported from the Eastern refugium, the Iberian refugium, or both.This work was partially supported by a research studentship from the Biotechnology and Biological Sciences Research Council (BB/E527604/1) and a PhD studentship from the German Academic Exchange Service (D/07/44562) to VW, and a Leverhulme Trust project grant (F/09 757/B) to MAB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

O cavalo Lusitano. Uma raca em recuperacao

Available from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1249-074 Lisboa, Portugal / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga

In vivo fertilizing ability of stallion spermatozoa processed by single layer centrifugation with

A colloid with a species specific silane-coated, silica-based formulation, optimized for stallion (Androcoll-E™), enables a better sub-population of spermatozoa to be selected from stallion ejaculates. However, such a practice has not been critically evaluated in stallions with fertility problems. In this study we evaluate whether single-layer centrifugation (SLC) through Androcoll-E™ could be used to enhance fertility rates in a subfertile stallion. Ejaculates were obtained from two different stallions, one Lusitano (fertile) and one Sorraia (subfertile), with distinct sperm characteristics and fertility. Motility, morphology, plasma membrane structural (eosin-nigrosin) and functional integrity (HOS test), mitochondrial functionality (Δψm; JC-1) and longevity (motility after 72 h cooling) after centrifugation in Androcoll-E™, as well as pregnancy rates obtained after artificial insemination (AI), with and without (control group) SLC-treated sperm were assessed. The effect of SLC on sperm characteristics, and fertility results were evaluated by ANOVA and Fisher procedures, respectively. Our results showed that SLC-selected sperm did not differ from the raw semen in terms of viability, morphology, response to hypo-osmotic conditions (HOS test) and mitochondrial membrane potential (↑ΔΨmit; JC-1). Sperm motility in cooled samples was not improved by SLC treatment. Our data show that SLC through Androcoll-E™ has no effect on pregnancy rates in the stallions used in this trial

Notes of the flea fauna (Insecta, Siphonaptera) of the terrestrial azorean mammals

peer reviewedDuring three successive years, field samplings of wild mammals were organised on different Azorean islands and the ectoparastes were collected. Among 340 murid rodents, 31 did bear at least one flea. Nosopsyllus l. londiniensis has been found on the mouse in São Miguel. Stenoponia t. tripectinata has been discovered in Terceira and in São Miguel, mainly on house mice and on one black rat out of 121. Nosopsyllus fasciatus was present on the mouse and on both the black and the Norway rats. Its presence has been evidenced in four islands: São Miguel, Terceira, Graciosa and Flores. Numerous rabbits were also examined in the visited islands (São Miguel, Terceira, Pico, São Jorge, Faial and Flores) and were found heavily parasited by their commonest flea, Spilopsyllus cuniculi. In Flores, however, that flea seems to be lacking. Though no systematic search has been done on domestic animals, the presence of Ctenocephalides f. felis is also reported from Flores, Terceira and Graciosa whereas C. canis has been found on a dog in Florès. The flea fauna of the Azorean archipelago is therefore characterized by a few species amongst the most cosmopolitan one

Bacteriogical evidence of leptospira infetion in wild mammals from Azores archipelago, Portugal (short report)

peer reviewedJNICT, STRDA/C/CEN/447/9

First approach on the skull morphology of the black rat (Rattus rattus) from Terceira and São Miguel islands (Azores archipelago)

peer reviewedThe present paper deals with an analysis of metric (cranial measurements) and non metric (epigenetic cranial characters) variation in black rat populations from S. Miguel and Terceira islands compared to a continental sample. Assuming the Azorean rats originate from the European continent, we tested the similarity between the samples, considering only adult and subadult animals. Having verified that there was no sexual dimorphism in the characters studied, we computed discriminant functions and made a PCA with the most discriminant variables. The three samples are clearly separated by these functions, the Azorean rats showing a larger general skull size and differing between the two islands. The Mean Measure of Divergence (MMD), based on non metric cranial traits frequencies, was also used to express the interpopulational differences: the rats of Terceira differ significantly either from the continental ones or from those of S. Miguel. Finally, the possible origin of these differences is disussed

Mammals from the Azores islands (Portugal): an updated overview

Nine species of mammals are recorded for the Azores islands: one insectivore (Erinaceus europaeus), two bats (Myotis myotis, Nyctalus azoreum), one lagomorph (Oryctolagus cuniculus), three rodents (Rattus norvegicus, R. rattus, Mus musculus domesticus) and two carnivores (Mustela nivalis, M. furo). Here, notes on the origin and known distribution are given for each species, together with taxonomical and ecological cmments. Except for bats all the remaining species seem to have been introduced under the influence of the man's exploratory and commercial activitie

First epidemiological data on pathogenic leptospires isolated on the Azorean islands

Insectivores (Erinaceus europaeus) and rodents (Rattus rattus, R. norvegicus and Mus musculus) from different islands of the Azores archipelago were found to carry three distinct Leptospira interrogans s.l. serovars (copenhageni, icterohaemorrhagiae and ballum) which have never been previously investigated there. The house mouse and the black rat were the major Leptospira reservoir showing isolation rates ranging from 0% for both species (in Graciosa) to 88 % and 33 %, respectively (in São Miguel). This study also showed that the majority of the animals with positive kidney cultures exhibited specific agglutinins agaibst the isolated strains of Leptospira. The observed isalation rates in the different islands, with a very interesting island variation in prevalence, suggest that small mammals, serving as sylvatic reservoirs of pathogenic leptospires, may represent an important risk to the health of humans and the livestock, particularly in the islands of Terceira and São Miguel