Molecular Epidemiology of Mycoplasma conjunctivae in Caprinae: Transmission across Species in Natural Outbreaks

Mycoplasma conjunctivae is the etiological agent of infectious keratoconjunctivitis, a highly contagious ocular infection that affects both domestic and wild Caprinae species in the European Alps. In order to study the transmission and spread of M. conjunctivae across domestic and wild Caprinae populations, we developed a molecular method for subtyping and identifying strains of M. conjunctivae. This method is based on DNA sequence determination of a variable domain within the gene lppS, a gene that encodes an antigenic lipoprotein of M. conjunctivae. This domain of lppS shows variations among different strains but remains constant upon generations of individual strains on growth medium and thus allows identification of individual strains and estimation of their phylogenetic intercorrelations. The variable domain of lppS is amplified by PCR using primers that match conserved sequences of lppS flanking it. Sequence analysis of the amplified fragment enables fine subtyping of M. conjunctivae strains. The method is applicable both to isolated strains and to clinical samples directly without requiring the cultivation of the strain. Using this method, we show that M. conjunctivae was transmitted between domestic and wild animals that were grazing in proximate pastures. Certain animals also presented infections with two different strains simultaneously.     

Occurrence, quantification, and genotyping of Mycoplasma conjunctivae in wild Caprinae with and without infectious keratoconjunctivitis

Mycoplasma conjunctivae, the causative agent of infectious keratoconjunctivitis (IKC), was recently detected in asymptomatic Alpine ibex (Capra ibex ibex). This suggested that an external source of infection may not be required for an IKC outbreak in wildlife but might be initiated by healthy carriers, which contradicted previous serologic investigations in chamois. Our aims were to 1) assess the prevalence of M. conjunctivae among asymptomatic ibex and Alpine chamois (Rupicapra rupicapra rupicapra) and its frequency in IKC-affected animals, 2) determine mycoplasma loads in different disease stages, and 3) characterize the M. conjunctivae strains involved. Eye swabs from 654 asymptomatic and 204 symptomatic animals were collected in diverse Swiss regions between 2008 and 2010, and tested by TaqMan real-time PCR. Data analysis was performed considering various patterns of IKC occurrence in the respective sampling regions. Strains from 24 animals were compared by cluster analysis. Prevalence of M. conjunctivae was 5.6% (95% confidence interval [CI]: 3.7-8.1%) in asymptomatic ibex and 5.8% (CI: 3.0-9.9%) in asymptomatic chamois, with significant differences between years and regions in both species. Detection frequency in symptomatic animals was significantly higher during IKC outbreaks than in nonepidemic situations (i.e., regular but low incidence or sporadic occurrence). Mycoplasma load was significantly lower in eyes from healthy carriers and animals with mild signs than from animals with moderate and severe signs. Although some strains were found in both asymptomatic and diseased animals of the same species, others apparently differed in their pathogenic potential depending on the infected species. Overall, we found a widespread occurrence of M. conjunctivae in wild Caprinae with and without IKC signs. Our results confirm the central role of M. conjunctivae in outbreaks but suggest that other infectious agents may be involved in IKC cases in nonepidemic situations. Additionally, presence and severity of signs are related to the quantity of M. conjunctivae in the eyes rather than to the strain. We propose that individual or environmental factors influence the clinical expression of the disease and that persistence of M. conjunctivae in populations of wild Caprinae cannot be excluded.     

Immune responses to Mycoplasma conjunctivae in alpine ibex, alpine chamois, and domestic sheep in Switzerland

The humoral immune response of three alpine chamois (Rupicapra rupicapra rupicapra), two alpine ibex (Capra ibex ibex) and three domestic sheep naturally affected with infectious keratoconjunctivitis (IKC), and four ibex and two sheep experimentally infected with Mycoplasma conjunctivae was analysed. In addition, the local immune response to M. conjunctivae was analysed using conjunctival washes from chamois and sheep. Immunoblot analysis of sera using whole cell antigens of M. conjunctivae revealed the major immunogenic proteins which had molecular masses of 175, 83, 68, 60, 50, 42, 36, and 33 kDa. Major antigens were found at 83, 68, 60, and 42 kDa in both sera and conjunctival washes from naturally infected animals of all three Caprinae species. In experimentally infected animals, antibodies to the 68 and 60 kDa antigens were dominant. Naturally infected animals showed much stronger immune reactions than those experimentally infected, and specific antibodies appeared 2 to 4 wk after experimental infection. To evaluate possible cross-reactions, whole cell antigen of M. conjunctivae was analysed by immunoblot against hyperimmune sera of closely related Mycoplasma spp. Antibodies to the 175, 73, 68, 60, and 33 kDa antigens appeared to be specific to M. conjunctivae. Cross-reactions mainly with 83, 50, and 42 kDa antigens were detected, in particular with M. ovipneumoniae and M. bovoculi hyperimmune sera, but also with antisera against M. capricolum capricolum and M. putrefaciens.     

Sexual size dimorphism in domestic goats,sheep, and their wild relatives

Sexual size dimorphism (SSD) is a widespread phenomenon in different animal taxa, including the subfamily of goats and sheep (Caprinae), which belongs to the most dimorphic mammalian groups. Rensch's rule describes the pattern of SSD, claiming that larger species generally exhibits higher male to female body size ratio. Agreement with Rensch's rule is manifested by slope of the allometric relationship between male and female body size exceeding one. To test this rule, we analysed the data available in the literature on adult body mass of males and females in domestic goat and sheep breeds (169 and 303, respectively) and 37 wild species/subspecies of the subfamily Caprinae. According to the current phylogenetical hypotheses, there are six distinct monophyletic groups with different levels of SSD (expressed as M/F): (1) wild goats (1.83); (2) wild sheep (1.67); (3) non‐European chamoises, including Ovibos moschatus (1.18); (4) European chamoises (1.27); (5) Budorcas taxicolor (1.01); and (6) Pantholops hodgsonii (1.65). Domestication has led to a remarkable decline in SSD of both domestic goats (1.36) and sheep (1.41). The highest regression slope of the relationship between male and female body size is that estimated for wild goats (1.32), followed by wild sheep (1.24), non‐European chamoises (1.14), domestic sheep (1.13), and domestic goats (1.10). Nevertheless, only the last two values are statistically different from one and thus corroborate Rensch's rule. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 872–883.     

Emergence of atypical Mycoplasma agalactiae strains harboring a new prophage and associated with an alpine wild ungulate mortality episode

The bacterium Mycoplasma agalactiae is responsible for contagious agalactia (CA) in small domestic ruminants, a syndrome listed by the World Organization for Animal Health and responsible for severe damage to the dairy industry. Recently, we frequently isolated this pathogen from lung lesions of ibexes during a mortality episode in the French Alps. This situation was unusual in terms of host specificity and tissue tropism, raising the question of M. agalactiae emergence in wildlife. To address this issue, the ibex isolates were characterized using a combination of approaches that included antigenic profiles, molecular typing, optical mapping, and whole-genome sequencing. Genome analyses showed the presence of a new, large prophage containing 35 coding sequences (CDS) that was detected in most but not all ibex strains and has a homolog in Mycoplasma conjunctivae, a species causing keratoconjunctivitis in wild ungulates. This and the presence in all strains of large integrated conjugative elements suggested highly dynamic genomes. Nevertheless, M. agalactiae strains circulating in the ibex population were shown to be highly related, most likely originating from a single parental clone that has also spread to another wild ungulate species of the same geographical area, the chamois. These strains clearly differ from strains described in Europe so far, including those found nearby, before CA eradication a few years ago. While M. agalactiae pathogenicity in ibexes remains unclear, our data showed the emergence of atypical strains in Alpine wild ungulates, raising the question of a role for the wild fauna as a potential reservoir of pathogenic mycoplasmas.     

Characterisation of Toxoplasma gondii isolates using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) of the non-coding Toxoplasma gondii (TGR)-gene sequences

The Toxoplasma gondii (TGR) genes constitute a family of non-coding sequences, three of which have been previously described as possible tools for typing of Toxoplasma gondii isolates. We obtained new isolates of T. gondii from domestic and wild animals, and used these to evaluate the possibility of using TGR gene variants as markers to distinguish among T. gondii isolates from different animals and different geographical sources.Based on the band patterns obtained by restriction fragment length polymorphism (RFLP) analysis of the polymerase chain reaction (PCR) amplified TGR sequences, the T. gondii isolates could be separated into seven groups. Sequencing the amplified products showed that at least 20 TGR sequences not hitherto described had been found, demonstrating that the TGR gene family comprises a large number of different yet highly homologous sequences. Each isolate had its own unique TGR sequence. The TGR gene family therefore seems a promising target for typing individual T. gondii isolates and for studying the genetic distance between two isolates, which can be used for tracing routes of infection.     

Mycoplasma conjunctivae infection is not maintained in alpine chamois in eastern Switzerland

The occurrence of infectious keratoconjunctivitis (IKC) was assessed in alpine chamois (Rupicapra rupicapra rupicapra) in Grisons (Switzerland) from 1950 to 1999. The first IKC outbreaks were reported in the 1950's. Since then, the number of affected subpopulations constantly increased and, by 1999, IKC outbreaks were reported in 39 of 51 (77%) chamois sub-populations. From 1992-99, a total of 243 chamois which died of the consequences of IKC were recorded. The number of cases differed between years, and a distinct seasonal trend was observed. Infectious keratoconjunctivitis was more common during summer and autumn, with 48% of the cases recorded in August-October. Juveniles (< 4 yr of age) were mostly represented. To verify the presence of Mycoplasma conjunctivae in chamois we analyzed conjunctival swabs taken from animals affected with IKC. Among a sample of 28 affected chamois, M. conjunctivae was identified 14 times (50%). An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect specific M. conjunctivae antibodies in sera of alpine chamois with IKC. We performed a serologic investigation to assess whether M. conjunctivae infection is self-maintained in the chamois population in Grisons. In subpopulations with IKC oubreaks, seroprevalence was low (8%). Seroprevalence was even lower in subpopulations with recent IKC outbreaks (3%). We concluded that the M. conjunctivae infection is not self-maintained in alpine chamois in Grisons. The agent may originate in domestic sheep living in proximity to chamois during summer. Control of IKC in chamois should consider immunoprophylaxis in sheep or limiting interspecific transmission of M. conjunctivae.     

Single-strand conformational polymorphism and sequence polymorphism of Mhc-DRB in Latxa and Karrantzar sheep: implications for Caprinae phylogeny

Single-strand conformational polymorphism analysis and DNA sequencing were used to characterize Mhc-DRB second exon variability in the Latxa and Karrantzar breeds of sheep. The presence of more than two sequences in some animals indicates that alleles of two different loci have been amplified. Six new alleles were identified by sequencing. The allele frequency distribution of the DRB1 gene is striking, with two alleles accounting for half of the gene pool in both breeds under study. The most frequent allele in both breeds was the same (named DRB1*0702), with some specific amino acids: Tyr in position 31 and Thr in 51. A species variability analysis was also performed including the entire set of sheep DRB exon 2 sequences. Based on the patchwork patterns of different alleles, interallelic recombination appears to be playing a significant role in the generation of allelic diversity at this locus in sheep. The phylogenetic tree of all known Caprinae DRB sequences shows that certain alleles from one species are more closely related to those from other species than they are to each other. Allele DRB1*0702 merits special attention due to its high similarity to the Mufflon allele. As this is the most frequent in both breeds analyzed, one can hypothesize that in sheep, both Mufflon and Argali have had different influences depending on the sheep breed under study and that the relationship between domestic sheep and Mufflon is greater than previously thought. The data generated in this study can serve as a basis for developing a typing assay for the sheep DRB genes in the Latxa and Karrantzar populations.     

Electrophoretic variation and differentiation in four strains of domesticated rainbow trout (Salmo gairdneri).

A total of 1462 rainbow trout (Salmo gairdneri Richardson) representing four California domestic strains, were examined electrophoretically at 24 gene loci to investigate the amount of genetic variability within strains and genetic differentiation between strains, relative to wild populations. Estimated heterozygosities of 0.071 to 0.134 were similar to those reported for wild populations and thus indicated that the domestic strains were at least as variable as wild populations. Genetic distances between strains ranged from 0.011 to 0.067, values typical of the level of differentiation observed between local conspecific populations in a variety of organisms. It was suggested that this high level of heterozygosity is due to mixing of populations in the strains' histories and perhaps also to balancing selection.     

Morphological characterisation of Australian strains of Echinococcus granulosus

Kumaratilake L. M. and Thompson R. C. A., 1984. Morphological characterisation of Australian strains of Echinococcus granulosus. International Journal for Parasitology14: 467–477. Previous studies utilising biochemical and developmental criteria demonstrated the occurrence of three distinct strains of E. granulosus in Australia. In order to further characterise these strains, we studied metacestode and adult morphology of E. granulosus of various domestic and wild animal origin from different geographical areas of Australia. Morphological comparisons included specimens from natural infections as well as experimentally-derived adult worms of known age. Three morphologically distinct populations of E. granulosus were recognised in domestic and wild animals. These populations corresponded to the three strains described previously on the basis of biochemical and developmental criteria. One strain is common to all domestic intermediate hosts on the Australian mainland, the second is confined to macropods on the mainland and the third to sheep in Tasmania. No evidence was found that domestic animals on the mainland are susceptible to the sylvatic macropod strain, whereas 15% of macropods examined were infected with the mainland domestic strain. Natural infections with both mainland strains were found in dogs and dingoes. The practical value of morphology as a criterion in taxonomic and speciation studies is discussed. Suggestions as to the probable origin of the three Australian strains of E. granulosus are given.     

Amelogenin cross-amplification in the family Bovidae and its application for sex determination

Sex-specific sequence variability of the amelogenin gene had been observed in a variety of mammalian species. In our study, the suitability of the amelogenin gene for sex determination in different species of the family Bovidae was examined. Based on a sequence insertion/deletion characteristic for X- and Y-specific amelogenin (AMELX and AMELY), PCR amplification on male and female genomic DNA from domestic and wild bovine species, sheep and goat, consistently displayed a sex-specific pattern. Thus, the amelogenin amplification by PCR proved to be a reliable method for sex determination not only in domestic and wild species of the tribe Bovini, but also in the related species sheep and goat. Sex determination using the amelogenin-based assay can be performed with at least 40 pg of genomic DNA. The assay enables the investigation of small amounts of DNA from meat, hair, bones, and embryo biopsies to identify species and sex for a number of applications in animal production, forensics, population research, and monitoring within the family Bovidae. Sequence comparison of the amplified amelogenin gene region specific for male and female animals from domestic and wild bovide species revealed further sequence variations within and between sexes as well as between species. Sequence variations in the AMELX gene can be applied to discriminate Bos and Bison individuals from other bovine species, and also from sheep and goat.     

Contrasting Mode of Evolution at a Coat Color Locus in Wild and Domestic Pigs

Despite having only begun ~10,000 years ago, the process of domestication has resulted in a degree of phenotypic variation within individual species normally associated with much deeper evolutionary time scales. Though many variable traits found in domestic animals are the result of relatively recent human-mediated selection, uncertainty remains as to whether the modern ubiquity of long-standing variable traits such as coat color results from selection or drift, and whether the underlying alleles were present in the wild ancestor or appeared after domestication began. Here, through an investigation of sequence diversity at the porcine melanocortin receptor 1 (MC1R) locus, we provide evidence that wild and domestic pig (Sus scrofa) haplotypes from China and Europe are the result of strikingly different selection pressures, and that coat color variation is the result of intentional selection for alleles that appeared after the advent of domestication. Asian and European wild boar (evolutionarily distinct subspecies) differed only by synonymous substitutions, demonstrating that camouflage coat color is maintained by purifying selection. In domestic pigs, however, each of nine unique mutations altered the amino acid sequence thus generating coat color diversity. Most domestic MC1R alleles differed by more than one mutation from the wild-type, implying a long history of strong positive selection for coat color variants, during which time humans have cherry-picked rare mutations that would be quickly eliminated in wild contexts. This pattern demonstrates that coat color phenotypes result from direct human selection and not via a simple relaxation of natural selective pressures.     

Sex determining of cat embryo and some feline species

Sex identification in mammalian preimplantation embryos is a technique that is used currently for development of the embryo transfer industry for zootechnical animals and is, therefore, a resource for biodiversity preservation. The aim of the present study was to establish a rapid and reliable method for the sexing of preimplantation embryos in domestic cats. Here we describe the use of nested PCR identify Y chromosome-linked markers when starting from small amounts of DNA and test the method for the purpose of sexing different species of wild felids. To evaluate the efficiency of the primers, PCR analysis were performed first in blood samples of sex-known domestic cats. Cat embryos were produced both in vitro and in vivo and the blastocysts were biopsied. A Magnetic Resin System was used to capture a consistent amount of DNA from embryo biopsy and wild felid hairs. The results from nested PCR applied on cat blood that corresponded to the phenotypical sex. Nested PCR was also applied to 37 embryo biopsies and the final result was: 21 males and 16 females. Furthermore, beta-actin was amplified in each sample, as a positive control for DNA presence. Subsequently, nested PCR was performed on blood and hair samples from some wild felines and again the genotyping results and phenotype sex corresponded. The data show that this method is a rapid and repeatable option for sex determination in domestic cat embryos and some wild felids and that a small amount of cells is sufficient to obtain a reliable result. This technique, therefore, affords investigators a new approach that they can insert in the safeguard programmes of felida biodiversity.     

Sequence of specific mitochondrial 16S rRNA gene fragment from Egyptian buffalo is used as a pattern for discrimination between river buffaloes,cattle, sheep and goats

Characterization of molecular markers and the development of better assays for precise and rapid detection of domestic species are always in demand. This is particularly due to recent food scares and the crisis of biodiversity resulting from the huge ongoing illegal traffic of endangered species. The aim of this study was to develop a new and easy method for domestic species identification (river buffalo, cattle, sheep and goat) based on the analysis of a specific mitochondrial nucleotide sequence. For this reason, a specific fragment of Egyptian buffalo mitochondrial 16S rRNA gene (422 bp) was amplified by PCR using two universal primers. The sequence of this specific fragment is completely conserved between all tested Egyptian buffaloes and other river buffaloes in different places in the world. Also, the lengths of the homologous fragments were less by one nucleotide (421 bp) in case of goats and two nucleotides (420 bp) in case of both cattle and sheep. The detection of specific variable sites between investigated species within this fragment was sufficient to identify the biological origin of the samples. This was achieved by alignment between the unknown homologous sequence and the reference sequences deposited in GenBank database (accession numbers, FJ748599–FJ748607). Considering multiple alignment results between 16S rRNA homologous sequences obtained from GenBank database with the reference sequence, it was shown that definite nucleotides are specific for each of the four studied species of the family Bovidae. In addition, other nucleotides are detected which can allow discrimination between two groups of animals belonging to two subfamilies of family Bovidae, Group one (closely related species like cattle and buffalo, Subfamily Bovinae) and Group two (closely related species like sheep and goat, Subfamily Caprinae). This 16S DNA barcode character-based approach could be used to complement cytochrome c oxidase I (COI) in DNA barcoding. Also, it is a good tool for identification of unknown sample belonging to one of the four domestic animal species of family Bovidae quickly and easily.     

Prevalence of Streptococcus suis genotypes in wild boars of Northwestern Germany

Invasive serotype 2 (cps2+) strains of Streptococcus suis cause meningitis in pigs and humans. Four case reports of S. suis meningitis in hunters suggest transmission of S. suis through the butchering of wild boars. Therefore, the objective of this study was to investigate the prevalence of potentially human-pathogenic S. suis strains in wild boars. S. suis was isolated from 92% of all tested tonsils (n=200) from wild boars. A total of 244 S. suis isolates were genotyped using PCR assays for the detection of serotype-specific genes, the hemolysin gene sly, and the virulence-associated genes mrp and epf. The prevalence of the cps2+ genotype among strains from wild boars was comparable to that of control strains from domestic pig carriers. Ninety-five percent of the cps2+ wild boar strains were positive for mrp, sly, and epf*, the large variant of epf. Interestingly, epf* was significantly more frequently detected in cps2+ strains from wild boars than in those from domestic pigs; epf* is also typically found in European S. suis isolates from humans, including a meningitis isolate from a German hunter. These results suggest that at least 10% of wild boars in Northwestern Germany carry S. suis strains that are potentially virulent in humans. Additional amplified fragment length polymorphism analysis supported this hypothesis, since homogeneous clustering of the epf* mrp+ sly+ cps2+ strains from wild boars with invasive human and porcine strains was observed.     

Domestication affects the structure,development and stability of biobehavioural profiles

Domestication is an evolutionary process during which the biobehavioural profile (comprising e.g. social and emotional behaviour, cognitive abilities, as well as hormonal stress responses) is substantially reshaped. Using a comparative approach, and focusing mainly on the domestic and wild guinea pig, an established model system for the study of domestication, we review (a) how wild and domestic animals of the same species differ in behaviour, emotion, cognition, and hormonal stress responses, (b) during which phases of life differences in biobehavioural profiles emerge and (c) whether or not animal personalities exist in both the wild and domestic form. Concerning (a), typical changes with domestication include increased courtship, sociopositive and maternal behaviours as well as decreased aggression and attentive behaviour. In addition, domestic animals display more anxiety-like and less risk-taking and exploratory behaviour than the wild form and they show distinctly lower endocrine stress responsiveness. There are no indications, however, that domestic animals have diminished cognitive abilities relative to the wild form. The different biobehavioural profiles of the wild and domestic animals can be regarded as adaptations to the different environmental conditions under which they live, i.e., the natural habitat and artificial man-made housing conditions, respectively. Concerning (b), the comparison of infantile, adolescent and adult wild and domestic guinea pigs shows that the typical biobehavioural profile of the domestic form is already present during early phases of life, that is, during early adolescence and weaning. Thus, differences between the domestic and the wild form can be attributed to genetic alterations resulting from artificial selection, and likely to environmental influences during the pre- and perinatal phase. Interestingly, the frequency of play behaviour does not differ between the domestic and wild form early in life, but is significantly higher in domesticated guinea pigs at later ages. Concerning (c), there is some evidence that personalities occur in both wild and domestic animals. However, there may be differences in which behavioural domains – social and sexual behaviour, emotionality, stress-responsiveness – are consistent over time. These differences are probably due to changing selection pressures during domestication.     

长爪沙鼠的遗传多样性分析

利用17个微卫星DNA标记对Z:ZCLA长爪沙鼠封闭群、野生群和近交系进行遗传多样性分析, 评估群体内的遗传变异和群体间的遗传分化。结果表明：在Z:ZCLA封闭群和野生群中共有9个微卫星DNA标记获得稳定的结果, 分别为AF200940、AF200941、AF200942、AF200945、AF200946、AF200947、D11Mit128、PKC和 SCN, 共检测到41个等位基因, 每个基因的等位基因数从1～7不等, 片段大小在120～283 bp之间, 所有位点的平均期望杂合度(He)和多态信息含量(PIC)值分别为0.5032和0.4656, Z:ZCLA封闭群和野生群9个微卫星位点平均有效等位基因数分别为2.78和2.89, 平均基因杂合度分别为0.3704和 0.3893, 平均多态信息含量分别为0.3256和0.3344, 两个群体都表现为中度多态, Z:ZCLA封闭群较野生群稍低; 在3个近交系中共有8个位点获得稳定的扩增结果, 分别为AF200941、AF200942、AF200945、AF200946、AF200947、D11Mit128、PKC和 SCN, 共检测到11个等位基因, 片段大小在140~241 bp之间, 其中5个位点在群体内表现为单态纯合, 3个位点在群体内表现为单态杂合, 所有位点在群体内和群体间均呈单态性, 表明这3个长爪沙鼠品系基本符合近交系的要求, 微卫星标记技术适用于近交系长爪沙鼠的遗传检测。     

Cross-species amplification of Bovidae microsatellites and low diversity of the endangered Korean goral

The Korean goral (Nemorhaedus caudatus) is an endangered species of wild goat. The conservation and management of this species could benefit from a better understanding of its genetic diversity and structure. Cross-species amplification of 34 Bovidae microsatellite loci was tested on a panel of 6 Korean gorals and 10 domestic goats. After polymerase chain reaction (PCR) optimization, 29 (85.3%) microsatellite loci amplified successfully for the Korean gorals and 27 (79.4%) for the domestic goats. Of the amplified products, 16 (55.2%) were polymorphic in the Korean goral and 22 (81.5%) in domestic goats. Nei's unbiased mean heterozygosity and mean allele number per locus were, respectively, 0.356 and 2.6 in the Korean goral and 0.636 and 4.8 in domestic goats. Low genetic diversity in the Korean gorals observed in this preliminary microsatellite survey suggests an urgent need for further detailed study of genetic diversity in Korean goral populations and a population management strategy based on these studies. Current results of cross-species amplification of domestic Bovidae microsatellites could be employed for the necessary population genetic studies on the Korean goral and other endangered Caprinae species.     

Characterization of Newcastle Disease Viruses in Wild and Domestic Birds in Luxembourg from 2006 to 2008

Newcastle disease virus (NDV) is one of the most important viral diseases of birds. Wild birds constitute a natural reservoir of low-virulence viruses, while poultry are the main reservoir of virulent strains. Exchange of virus between these reservoirs represents a risk for both bird populations. Samples from wild and domestic birds collected between 2006 and 2010 in Luxembourg were analyzed for NDV. Three similar avirulent genotype I strains were found in ducks during consecutive years, suggesting that the virus may have survived and spread locally. However, separate introductions cannot be excluded, because no recent complete F gene sequences of genotype I from other European countries are available. Detection of vaccine-like strains in wild waterbirds suggested the spread of vaccine strains, despite the nonvaccination policy in Luxembourg. Among domestic birds, only one chicken was positive for a genotype II strain differing from the LaSota vaccine and exhibiting a so-far-unrecognized fusion protein cleavage site of predicted low virulence. Three genotype VI strains from pigeons were the only virulent strains found. The circulation of NDV in wild and free-ranging domestic birds warrants continuous surveillance because of increased concern that low-virulence wild-bird viruses could become more virulent in domestic populations.     

Nucleotide variation in wild and inbred mice

The house mouse is a well-established model organism, particularly for studying the genetics of complex traits. However, most studies of mice use classical inbred strains, whose genomes derive from multiple species. Relatively little is known about the distribution of genetic variation among these species or how variation among strains relates to variation in the wild. We sequenced intronic regions of five X-linked loci in large samples of wild Mus domesticus and M. musculus, and we found low levels of nucleotide diversity in both species. We compared these data to published data from short portions of six X-linked and 18 autosomal loci in wild mice. We estimate that M. domesticus and M. musculus diverged <500,000 years ago. Consistent with this recent divergence, some gene genealogies were reciprocally monophyletic between these species, while others were paraphyletic or polyphyletic. In general, the X chromosome was more differentiated than the autosomes. We resequenced classical inbred strains for all 29 loci and found that inbred strains contain only a small amount of the genetic variation seen in wild mice. Notably, the X chromosome contains proportionately less variation among inbred strains than do the autosomes. Moreover, variation among inbred strains derives from differences between species as well as from differences within species, and these proportions differ in different genomic regions. Wild mice thus provide a reservoir of additional genetic variation that may be useful for mapping studies. Together these results suggest that wild mice will be a valuable complement to laboratory strains for studying the genetics of complex traits.