Ten markers specific to Sarcoptes mites were used in applying microsatellite genotyping to individual Sarcoptes mites collected in three European countries from 15 wild mammal populations belonging to 10 host species. The results showed that geographical separation had real biological significance for the definition of mite sub-populations, and that the degree of genetic exchange occurring between mites from different localities was apparently related to the geographical distance between locations. Wild hostderived mite populations were found to be clustered into three main groups: herbivore-, carnivoreand omnivore-derived Sarcoptes populations, with the omnivore-derived group located halfway between the herbivore-and carnivore-derived Sarcoptes populations. The separation between these three mite groups was better supported than the geographical separations; nevertheless, a kind of sub-clustering was detected within each of these three groups that separates mite populations into their geographical localities (countries). The lack of gene flow between Sarcoptes populations may have improved parasitic adaptations and led to what we refer to as a host-taxon-derived (carnivore host-, herbivore host-and omnivore host-derived) Sarcoptes mite found on European wild animals. Our results demonstrate that Sarcoptes is not a single panmictic population, even within each geographical location. This finding will have important ramifications for the study of the genetic structure of populations, life cycles, diagnosis and the monitoring protocols of the ubiquitous Sarcoptes mite, and could thus contribute to a better understanding of its associated epidemiology, which is of pivotal interest for wildlife biological conservation.

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Degenerative myelopathy is a late-onset, slowly progressive degeneration of spinal cord white 2 matter which is reported primarily in large breed dogs. The missense mutation SOD1:c.118G>A is 3 associated with this pathology in several dog breeds, including the German Shepherd Dog. The 4 aims of the present study were to develop a tool for the rapid screening of the SOD1 mutation site in 5 dogs and to evaluate the association of the polymorphism with degenerative myelopathy in the 6 German Shepherd breed. Two different techniques were compared: a minisequencing test and a 7 Real-Time PCR Allelic Discrimination assay. Both approaches resulted effective and efficient. A 8 sample of 47 dogs were examined. Ten subjects presented the symptoms of the illness; for one of 9 them the diagnosis was confirmed by postmortem investigations and it resulted to be an A/A 10 homozygote. In another clinically suspected dog, heterozygote A/G, the histopathological 11 examination of the medulla showed moderate axon and myelin degenerative changes. German 12 Shepherd Dog shows a frequency of the mutant allele equal to 0.17, quite high being a high-risk 13 allele. Because canine degenerative myelopathy has a late onset in adulthood and homozygous 14 mutant dogs are likely as fertile as other genotypes, the natural selection is mild and the mutant 15 allele may reach high frequencies. A diagnostic test, easy to implement, may contribute to control 16 the gene diffusion in populations. The SOD1:c.118G>A mutation could be a useful marker for 17 breeding strategies intending to reduce the incidence of degenerative myelopathy.

Analysis of the genetic diversity of the Alpine chamois in Italy was conducted using a pool of 26 microsatellite loci. A total of 209 animals were analyzed, representing six geographical populations from different location of the Southern slope of the Alps. Clear genetic differences have emerged between the sampled chamois groups. Some were consistent with an isolation-by-distance model. However, in parallel, other mechanisms intervened in areas that, in addition to being peripheral to the main alpine ridge, had suffered from recent bottlenecks. In such areas, genetic drift and a low rate of gene flow are likely explanations for the current genetic structure.

Availability of mites is a recognized limiting factor of biological and genetic investigations of the genus Sarcoptes. Current methods of deoxyribonucleic acid (DNA) extraction from individual mites also need substantial improvement in efficiency and operator friendliness. We have first developed a technique for efficient and safe extraction of living mites from scabietic skin samples (crusts or deep skin scrapings). Its core device is a large plastic syringe connected with a 1.5-ml Eppendorf tube. The source material is introduced in the syringe and the device in a shoe box with the tip half of the tube emerging. Mites migrate towards a heat source during a minimum of 36 h. Then, the tube is detached and the mites utilized without risks for the operators. A second technique allows operator-friendly manipulation of individual mites for DNA extraction. Fixed mites are isolated by adhesion to a small strip of polyvinyl chloride (PVC) adhesive tape operated with tweezers. Then, mite and strip are plunged in the lyses buffer and the sample twice submitted to thermal shock for disruption of the chitinous exoskeleton. Data show that the tape does not interfere with successive DNA extraction with a commercial kit. The corresponding protocol, that we briefly name "PVC adhesive tape + thermal shock + kit DNA extraction," compares favorably with the available ones.