Variation in V lambda genes in the genus Mus

The complement of Ig V lambda genes in nine species of feral mice representing the four extant subgenera of the genus Mus was examined and compared with that of BALB/c inbred mice. Although all inbred strains examined have two V lambda genes, there is variation in the number of copies of V lambda genes in the wild mice. All feral representatives of M. musculus domesticus, from which inbred strains are derived, have at least three V lambda genes, indicating that a V lambda gene may have been lost during the inbreeding process. At least three V lambda genes are also found in representatives of three other M. musculus subspecies, including the stock of M. musculus musculus "Czech II" shown to have at least 12 C lambda genes. In comparing the complement of V lambda and C lambda genes in these animals, evidence is found that supports a mechanism of lambda gene reiteration involving duplication of a unit containing a V lambda and two C lambda genes. However, the possibility that C lambda gene amplification occurred independent of V lambda gene evolution cannot be ruled out. M. spicelegus and M. spretus, species that are semifertile with M. musculus, have one to three V lambda genes. Species more distantly related to M. musculus, such as M. cookii and M. platythrix, appear to have more (four to six) V lambda genes. Greater V lambda gene heterogeneity is also found in these animals. We propose that the ancestors of the subgenus Mus had more V lambda genes than are seen in modern species and that the paucity of V lambda genes in M. musculus, M. spicelegus, and M. spretus may be the result of V lambda gene deletion events that occurred since the divergence of the ancestor of these three species and those of the distantly related species.     

Inbreeding depression in ring-tailed lemurs (<Emphasis Type="Italic">Lemur catta</Emphasis>): genetic diversity predicts parasitism,immunocompetence, and survivorship

The consequences of inbreeding have been well studied in a variety of taxa, revealing that inbreeding has major negative impacts in numerous species, both in captivity and in the wild; however, as trans-generational health data are difficult to obtain for long-lived, free-ranging species, similar analyses are generally lacking for nonhuman primates. Here, we examined the long-term effects of inbreeding on numerous health estimates in a captive colony of ring-tailed lemurs (Lemur catta), housed under semi-natural conditions. This vulnerable strepsirrhine primate is endemic to Madagascar, a threatened hotspot of biodiversity; consequently, this captive population represents an important surrogate. Despite significant attention to maintaining the genetic diversity of captive animals, breeding colonies invariably suffer from various degrees of inbreeding. We used neutral heterozygosity as an estimate of inbreeding and showed that our results reflect genome-wide inbreeding, rather than local genetic effects. In particular, we found that genetic diversity affects several fitness correlates, including the prevalence and burden of Cuterebra parasites and a third (N = 6) of the blood parameters analyzed, some of which reflect immunocompetence. As a final validation of inbreeding depression in this captive colony, we showed that, compared to outbred individuals, inbred lemurs were more likely to die earlier from diseases. Through these analyses, we highlight the importance of monitoring genetic variation in captive animals—a key objective for conservation geneticists—and provide insight into the potential negative consequences faced by small or isolated populations in the wild. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Zur Haltung von Dallschafen (Ovis dalli) im Zoologischen Garten Leipzig: Keeping Dall's Sheep (Ovis dalli) at Leipzig Zoo

Keeping and breeding Dall's Sheep (Ovis dalli) in Leipzig Zoo between 1982 and 2009 are reflected and analysed. Seven animals were brought into the collection. 60 specimens were kept so far. The species hast turned out to be difficult in Middle-Europe‘s climate but nevertheless is manageable and reproductive. The rearing rate (animals have reached at least the age of 1 year) is 40%. Remarkable veterinarian treatments for keeping the stock healthy and especially for ensuring the breeding are described. For sure, deep engagement of keepers, veterinarians and curators is needed to keep this species successfully. Hopefully a lot of colleagues will take this as a challenge to increase numbers in Europe by joining the group of holders of this splendid wild sheep.     

The helminth fauna of wild and domestic ruminants in Mongolia—a review

The helminth fauna of eight species of wild ruminants and five species of domestic ruminants sharing common grassland in Mongolia was reviewed. A total of 108 species of helminths, belonging to 40 genera, 23 families, 11 superfamilies, 6 orders and 3 classes were reported in wild and domestic ruminants in Mongolia. Several new host–helminth associations have been recorded. Twenty seven helminth species have been found in certain host species for the first time in Mongolia. These included 2 species of trematodes, 2 species of cestodes and 23 species of nematodes. Helminths that are specific for some of the examined ruminant species were determined. However, wild animals may serve as a reservoir of helminth infections for domestic animals when sharing grassland in Mongolia. The helminth fauna of the ruminants with respect to occurrence, distribution, prevalence and intensity of infection was considered for six geographic regions of Mongolia.     

Sensitive males: inbreeding depression in an endangered bird

Attempts to conserve threatened species by establishing new populations via reintroduction are controversial. Theory predicts that genetic bottlenecks result in increased mating between relatives and inbreeding depression. However, few studies of wild sourced reintroductions have carefully examined these genetic consequences. Our study assesses inbreeding and inbreeding depression in a free-living reintroduced population of an endangered New Zealand bird, the hihi (Notiomystis cincta). Using molecular sexing and marker-based inbreeding coefficients estimated from 19 autosomal microsatellite loci, we show that (i) inbreeding depresses offspring survival, (ii) male embryos are more inbred on average than female embryos, (iii) the effect of inbreeding depression is male-biased and (iv) this population has a substantial genetic load. Male susceptibility to inbreeding during embryo and nestling development may be due to size dimorphism, resulting in faster growth rates and more stressful development for male embryos and nestlings compared with females. This work highlights the effects of inbreeding at early life-history stages and the repercussions for the long-term population viability of threatened species.     

A review on fisheries and conservation status of Asian horseshoe crabs

Horseshoe crabs are the only extant xiphosurans and are believed to be morphologically unchanged for more than 200 million years. Of the four extant species namely, Limulus polyphemus, Tachypleus tridentatus, Tapinauchenius gigas and Carcinoscorpius rotundicauda, the latter three are found in Asian waters. Recent evidences showed that Asian horseshoe crabs are facing serious threats such as degradation of their spawning grounds and habitat, environmental pollution, overexploitation as a culinary delicacy and biomedical bleeding practices. Baseline data on the distribution and existing population of the wild horseshoe crabs remain poorly known in several Asian regions. Several studies have clearly revealed that pressure due to over-fishing of wild stock has increased tremendously in the last decade. Due to an increase in demand for Tachypleus Amebocyte Lysate (TAL) analogous to Limulus Amebocyte Lysate (LAL) in the United States, there is an urgent need to comprehensively address their fishing and conservation measures in the Asian region. This review addresses the overall studies on three species of Asian horseshoe crabs in relation to their fishing practices, local exploitation of their wild stock either for human consumption (or) by biomedical industries. The authors have structured the discussion on an international scale to address the existing problems in fishing and conservation of horseshoe crabs. Since no specific regulatory force or legislative protection act or a policy to preserve their natural stock are available to this date, this paper strongly recommends representative countries to include horseshoe crabs under their wildlife protection act to avoid further unsustainable exploitation of their wild populations.     

Assessing the genetic effects of rehabilitating harbor seals (<Emphasis Type="Italic">Phoca vitulina</Emphasis>) in the Wadden Sea using stochastic simulations

Rehabilitation of marine mammals with the intent of releasing them back into nature is carried out for several species. Rehabilitation can help supporting critically endangered species, increase public awareness, and serve scientific purposes, but rehabilitation also causes concern due to risk of introducing diseases into the wild populations and genetic changes from disruption of natural selection and host-pathogen co-evolution. In this study, we investigate another potential risk from rehabilitation that has not previously been considered, i.e., anthropogenic increase in population inbreeding level. For this purpose, we performed stochastic population viability analyses of the Wadden Sea harbor seal population using VORTEX. In the Wadden Sea, rehabilitation takes place in several rehabilitation centers, and many of the seals suffer from parasitic bronchopneumonia or are orphaned. Several studies have found a correlation between helminth infection and inbreeding level. Moreover, a relation between fitness traits such as pup survival and inbreeding has been demonstrated. On this basis, we assess the effects from rehabilitating relatively inbred seals on population size and genetic diversity. We find that releasing seals significantly affect population inbreeding level and to a lesser extent population size. The effect depends on the level of inbreeding in rehabilitated seals as well as the actual number of inbred seals released.     

Possible negative effects of inbreeding on semen quality in Shetland pony stallions

Inbreeding is widely believed to negatively affect reproductive performance. Indeed, in some species, high levels of inbreeding are thought to be the major cause of poor semen quality. It is, however, not clear whether inbreeding affects fertility in horses. In this study, the relationship between inbreeding and semen quality was examined in 285 immature Shetland pony stallions submitted for breeding soundness examination in March-April of the years 1992-1997. The majority of stallions examined were 3 years old (85%) and their coefficients of inbreeding ranged from 0 to 25% (mean+/-S.D.: 3+/-4.6%). For the purpose of analysis, stallions were divided into six inbreeding classes (0-1, 1-2, 2-5, 5-8, 8-12 and >12%) containing 132, 40, 42, 27, 25 and 19 animals, respectively. The degree of inbreeding significantly affected many aspects of sperm production and quality, based on a standard examination of two ejaculates collected at a 1.5-3h interval. In particular, coefficients of inbreeding above 2% were associated with lower percentages of motile (p<0.01) and morphologically normal sperm (p<0.001). When the data set was used to estimate heritability of semen characteristics, the high values calculated for sperm progressive motility (0.46) and concentration (0.24) suggested that these traits could be improved by phenotypic selection. These findings support the hypothesis that inbreeding has a detrimental effect on semen quality in Shetland ponies, although examination of multiple ejaculates after repeated semen collection to bring the animals to daily sperm output is needed to confirm this conclusion. Nevertheless, the results support previous suggestions that inbreeding is an important cause of reduced semen quality.     

Group living and inbreeding depression in a subsocial spider

Social spiders are unusual among social organisms in being highly inbred-males and females mature within their natal nest and mate with each other to produce successive generations. Several lines of evidence suggest that in spiders inbred social species originated from outbred subsocial ancestors, a transition expected to have been hindered by inbreeding depression. As a window into this transition, we examined the fitness consequences of artificially imposed inbreeding in the naturally outbred subsocial spider Anelosimus cf. jucundus. Subsocial spiders alternate periods of solitary and social living and are thought to resemble the ancestral system from which the inbred social species originated. We found that inbreeding depression in this subsocial spider only becomes evident in spiders raised individually following the end of their social phase and that ecological and demographic factors such as eclosion date, number of siblings in the group and mother's persistence are more powerful determinants of fitness during the social phase. A potential explanation for this pattern is that maternal care and group living provide a buffer against inbreeding depression, a possibility that may help explain the repeated origin of inbred social systems in spiders and shed light on the origin of other systems involving regular inbreeding.     

Inbreeding depression in non-human primates: a historical review of methods used and empirical data

Offspring born to related parents may show reduced fitness due to inbreeding depression. Although evidence of inbreeding depression has accumulated for a variety of taxa during the past two decades, such analyses remain rare for primate species, probably because of their long generation time. However, inbreeding can have important fitness costs and is likely to shape life-history traits in all living species. As a consequence, selection should have favored inbreeding avoidance via sex-biased dispersal, extra-group paternity, or kin discrimination. In this paper, we review empirical studies on the effects of inbreeding on fitness traits or fitness correlates in primate species. In addition, we report the methods that have been used to detect inbreeding in primate populations, and their development with the improvement of laboratory techniques. We focus particularly on the advantages and disadvantages using microsatellite loci to detect inbreeding. Although the genetic data that are typically available (partial pedigrees, use of microsatellite heterozygosity as an estimate of genomewide inbreeding) tend to impose constraints on analyses, we encourage primatologists to explore the potential effects of inbreeding if they have access to even partial pedigrees or genetic information. Such studies are important because of both the value of basic research in inbreeding depression in the wild and the conservation issues associated with inbreeding, particularly in threatened species, which include more than half of the currently living primate species.     

Evidence for frequent incest in a cooperatively breeding mammal

As breeding between relatives often results in inbreeding depression, inbreeding avoidance is widespread in the animal kingdom. However, inbreeding avoidance may entail fitness costs. For example, dispersal away from relatives may reduce survival. How these conflicting selection pressures are resolved is challenging to investigate, but theoretical models predict that inbreeding should occur frequently in some systems. Despite this, few studies have found evidence of regular incest in mammals, even in social species where relatives are spatio-temporally clustered and opportunities for inbreeding frequently arise. We used genetic parentage assignments together with relatedness data to quantify inbreeding rates in a wild population of banded mongooses, a cooperatively breeding carnivore. We show that females regularly conceive to close relatives, including fathers and brothers. We suggest that the costs of inbreeding avoidance may sometimes outweigh the benefits, even in cooperatively breeding species where strong within-group incest avoidance is considered to be the norm.     

Parental genetic characteristics and hatching success in the spotless starling, Sturnus unicolor

Several studies have shown that inbreeding causes low hatching success. However, it is not always clear under which parental genetic characteristics hatching failure occurs. We examined the effects of parental homozygosity and parental genetic similarity on egg hatchability in the spotless starling. We evaluated whether low hatchability was a consequence of genetic similarity of the parents producing a zygote or because the parents themselves had reduced fertility because of their own genetic characteristics. We found a significant detrimental effect of both highest and lowest female homozygosity on hatchability. Parental genetic similarity was negatively related to egg hatchability. In contrast, we found no significant effect of male homozygosity on hatching success. Our results suggest that effects of homozygosity on hatching success may be relevant even in populations of abundant and colonial wild bird species without geographical barriers that could limit immigration or dispersal. We also highlight the importance of the analyses of male and female homozygosity and parental genetic similarity when investigating related fitness consequences of inbreeding.     

Inbreeding depression influences lifetime breeding success in a wild population of red deer (Cervus elaphus)

Evolutionary and conservation biologists have a long-standing interest in the consequences of inbreeding. It is generally recognized that inbred individuals may experience reduced fitness or inbreeding depression. By the same token, relatively outbred individuals can have greater than average fitness, i.e. heterosis. However, nearly all of the empirical evidence for inbreeding depression comes from laboratory or domestic species. Inbreeding depression and heterosis are difficult to detect in natural populations due to the difficulties in establishing pedigrees. An alternative method is to correlate heterozygosity, which is measured using genetic markers, with a trait related to fitness. The typically studied traits, such as juvenile survival and growth rates, either cover only early life or are weakly correlated with lifetime breeding success (LBS). In this paper we show that heterozygosity is positively associated with male and female adult LBS in a wild population of red deer (Cervus elaphus) on the Isle of Rum, Scotland. To the authors' knowledge, this is the first time that inbreeding depression and/or heterosis have been detected for a trait highly correlated with overall fitness in both sexes in a wild population.     

Patterns of mating-system evolution in hermaphroditic animals: correlations among selfing rate, inbreeding depression, and the timing of reproduction

In hermaphrodites, traits that influence the selfing rate can coevolve with inbreeding depression, leading to the emergence of evolutionary syndromes. Theory predicts a negative correlation between inbreeding depression and selfing rate across species. This prediction has only been examined and validated in vascular plants. Furthermore, selfing rates are often influenced by environmental conditions (e.g., lack of mates or pollinators), and species are predicted to evolve mechanisms to buffer this variation. We extend previous studies of mating-system syndromes in two ways. First, we assembled a new dataset on Basommatophoran snails (17 species, including new data on 12 species). Second, we measured how species responded to variation in mate availability. Specifically, we quantified the waiting time before selfing (i.e., how long the onset of reproduction is delayed in the absence of mates). Selfing rates were negatively correlated with both inbreeding depression and the waiting time. Species with stronger inbreeding depression exhibited longer waiting times. These patterns obtained on Basommatophorans still hold when including eight other hermaphroditic animals. Our results support the hypothesis that selection drives the evolution of mating-system syndromes in animals. The reaction norm of selfing rates to mate availability is a key target of natural selection in this context.     

Isolation and characterization of microsatellite DNA markers in the rare species barfin flounder (Verasper moseri) and its closely related species spotted halibut (V. variegatus)

Barfin flounder and spotted halibut have been selected in Japan as target species for stock enhancement due to the fact that the number of individuals of these species in the wild has been decreasing in the last three decades. Barfin flounder is now considered to be a rare species as its situation is critical. The first microsatellite DNA markers for barfin flounder and spotted halibut are described in this study. Cross‐amplification of barfin flounder markers was examined in spotted halibut species and vice versa.     

ACTIVITY RHYTHMS OF WILD AND LABORATORY GOLDEN HAMSTERS (MESOCRICETUS AURATUS) UNDER ENTRAINED AND FREE-RUNNING CONDITIONS

The golden hamster (Mesocricetus auratus) is one of the most frequently used laboratory animals, particularly in chronobiological studies. One reason is its very robust and predictable rhythms, although the question arises whether this is an inbreeding effect or rather is typical for the species. We compared the daily (circadian) activity rhythms of wild and laboratory golden hamsters. The laboratory hamsters were derived from our own outbred stock (Zoh:GOHA). The wild hamsters included animals captured in Syria and their descendants (F1). Experiments were performed under entrained (light: dark [LD] 14h:10h) and under free-running (constant darkness, DD) conditions. Locomotor activity was recorded using passive infrared detectors. Under entrained conditions, the animals had access to a running wheel for a certain time to induce additional activity. After 3 weeks in constant darkness, a light pulse (15 min, 100 lux) was applied at circadian time 14 (CT14). Both laboratory and wild hamsters showed well-pronounced and very similar activity rhythms. Under entrained conditions, all hamsters manifested about 80% of their total 24h activity during the dark portion of the LD cycle. The robustness of the daily rhythms was also similar. However, interindividual variability was higher in wild hamsters for both measures. All animals used the running wheels almost exclusively during the dark portion of the LD cycle, although the wild hamsters were three times more active. The period length, measured in constant darkness, was significantly shorter in wild (23.93h ± 0.10h) than in laboratory hamsters (24.06 ± 0.07h). The light-induced phase changes were not different (about 1.5h). In summary, these results indicate that the laboratory hamster is not much different from the wild type. (Chronobiology International, 18(6), 921-932, 2001)     

Runs of homozygosity have utility in mammalian conservation and evolutionary studies

Runs of homozygosity (ROHs) arise due the transmission from parents to offspring of segments that are either identical by decent (IBD) or identical by state (IBS). The former is due to consanguineous matings whereas the latter is due to demographic processes. ROHs reduce individual nucleotide diversity (θ) as a function of homozygosity, and thus ROH distributions and θ are expected to vary among species because inbreeding levels, recombination rates, and demographic histories vary widely. To help interpret genetic diversity within and among species, we utilized genome sequence data from 78 mammalian species to compare θ and ROH burden (i.e., number and length of ROHs in the genome) among groups of mammals to assess genomic signatures of inbreeding. We compared θ and ROHs: (i) among threatened and non-threatened mammals to determine the significance of contemporary conservation status; (ii) among carnivorous and non-carnivorous mammals to determine the relevance of trophic effects; (iii) relative to body size because mutation rates generally vary with body mass; and (iv) across mammals from different latitudes to test for gradients in genomic diversity (e.g., due to effects of historic climatic regimes). Our results illustrate the considerable variance in genomic diversity across mammals, and that trophic level, body mass, and latitude have significant effects on θ and ROH burden. However, conservation status was not a reliable indicator of genomic diversity. We argue that genetic or genomic diversity should be an explicit component of conservation status, as such diversity is critical to the long-term sustainability of populations, and anticipate that ROHs will become more commonly used to estimate inbreeding in wild animals.     

On the evolutionary stability of the female-biased sex ratio in the wood lemming (Myopus schisticolor): the effect of inbreeding.

The evolutionary stability of the female-biased sex ratio observed in the wood lemming (Myopus schisticolor) is discussed. The hypothesis analysed is that the skewed sex ratio is maintained as a result of partial and/or recurrent inbreeding. Fredga et al. (1976, 1977) have suggested that an X-linked mutant gene, X, affects the male-determining action of the Y chromosome, thus converting some XY individuals into females. By a mechanism of selective non-disjunction in the foetal ovary only X-carrying eggs are produced. In particular the stability of that genetic mechanism (or the X chromosome) is analysed by considering the introduction of a "suppressing" sex-linked mutant gene Y. Several deterministic simulation models assuming father-daughter and/or brother-sister matings have been developed and analysed. It is concluded that in the case of extremely strong inbreeding, the hypothesised genetic mechanism may, as a result, be evolutionarily stable. Interpreting field observations on microtine rodents in general it is concluded that only a few species are likely to experience such extreme cases of inbreeding. The wood lemming and the related collared lemming (Dicrostonyx troquatus), another case which seems to have XY-females, are likely to exhibit sufficiently strong inbreeding.     

Survival of captive-born Ovis canadensis in North American zoos

The survival rate of North American bighorn sheep, Ovis canadensis, housed in several zoological gardens was analyzed. Complete herd histories, including birth and death data as well as causes of mortality, were collected from seven institutions. Lambs were divided into inbred and noninbred animals, with lambs being considered inbred if they had an inbreeding coefficient greater than zero. The rate of survival of inbred and noninbred lambs was compared using “survival equalling one year” and “survival equalling six months.” Another analysis compared the survival rate of male and female inbred lambs and male and female noninbred lambs. Age at death was also compared in inbred and noninbred lambs. The analysis of the data for the seven collections, located in various geographic areas and housing various subspecies, indicates that inbreeding depression is a mortality factor in the captive management of North American bighorn sheep. Therefore, long-term survival of captive or isolated wild populations will depend on maintaining genetic diversity within the herds through careful selection of breeding stock in captive populations and introduction of nonrelated animals into isolated wild populations.     

The imprecision of heterozygosity-fitness correlations hinders the detection of inbreeding and inbreeding depression in a threatened species

In nonpedigreed wild populations, inbreeding depression is often quantified through the use of heterozygosity-fitness correlations (HFCs), based on molecular estimates of relatedness. Although such correlations are typically interpreted as evidence of inbreeding depression, by assuming that the marker heterozygosity is a proxy for genome-wide heterozygosity, theory predicts that these relationships should be difficult to detect. Until now, the vast majority of empirical research in this area has been performed on generally outbred, nonbottlenecked populations, but differences in population genetic processes may limit extrapolation of results to threatened populations. Here, we present an analysis of HFCs, and their implications for the interpretation of inbreeding, in a free-ranging pedigreed population of a bottlenecked species: the endangered takahe (Porphyrio hochstetteri). Pedigree-based inbreeding depression has already been detected in this species. Using 23 microsatellite loci, we observed only weak evidence of the expected relationship between multilocus heterozygosity and fitness at individual life-history stages (such as survival to hatching and fledging), and parameter estimates were imprecise (had high error). Furthermore, our molecular data set could not accurately predict the inbreeding status of individuals (as 'inbred' or 'outbred', determined from pedigrees), nor could we show that the observed HFCs were the result of genome-wide identity disequilibrium. These results may be attributed to high variance in heterozygosity within inbreeding classes. This study is an empirical example from a free-ranging endangered species, suggesting that even relatively large numbers (>20) of microsatellites may give poor precision for estimating individual genome-wide heterozygosity. We argue that pedigree methods remain the most effective method of quantifying inbreeding in wild populations, particularly those that have gone through severe bottlenecks.