Dietmar Lieckfeldt

When the American sea sturgeon swam east

The two species of Atlantic sea sturgeon on either shore of the North Atlantic, Acipenser sturio in Europe and A. oxyrinchus in North America, probably diverged with the closure of the Tethys Sea and the onset of the North Atlantic Gyre 15–20 million years ago, and contact between them was then presumably precluded by geographic distance. Here we present genetic, morphological and archaeological evidence indicating that the North American sturgeon colonized the Baltic during the Middle Ages and replaced the native sturgeon there, before recently becoming extinct itself in Europe as a result of human activities. In addition to representing a unique transatlantic colonization event by a fish that swims upriver to spawn, our findings have important implications for projects aimed at restocking Baltic waters with the European sturgeon.

An exceptional case of historical outbreeding in African sable antelope populations

Empirical investigations of intraspecific outbreeding and subsequent introgressive hybridization in natural populations are rare, particularly among conspecific populations of large mammals. Using mitochondrial DNA data [partial control region (496 basepairs — bp) and cytochrome b gene (343 bp) sequences analysed from 95 individuals representing 17 sampling locations scattered through the African miombo (Brachystegia) woodland ecosystem] and phylogeographical statistical procedures (gene genealogy, nested cladistic and admixture proportion analyses), we (i) give a detailed dissection of the geographical genetic structure of Hippotragus niger; (ii) infer the processes and events potentially involved in the population history; and (iii) trace extensive introgressive hybridization in the species. The present‐day sable antelope population shows a tripartite pattern of genetic subdivision representing West Tanzanian, Kenya/East Tanzanian and Southern Africa locations. Nested clade analysis revealed that past allopatric fragmentation, caused probably by habitat discontinuities associated with the East African Rift Valley system, together with intermediary episodic long‐distance colonization and restricted, recurrent gene flow have played an predominant role in shaping the extent of maternal genetic diversity (10.4%) and population structure. An extensive (average rate of admixture = 20.0%), but geographically circumscribed and unidirectional hybridization event in the past was inferred, resulting in an extreme (the highest discovered so far in mammals) intraspecific difference of 18.2% among morphologically monotypic sable antelopes from West Tanzania. The results are used to provide an evolutionary framework within which taxonomic implications and conservation decisions can be evaluated.

Population subdivision in Europe’s great bustard inferred from mitochondrial and nuclear DNA sequence variation

A continent‐wide survey of sequence variation in mitochondrial (mt) and nuclear (n) DNA of the endangered great bustard (Otis tarda) was conducted to assess the extent of phylogeographic structure in a morphologically monotypic bird. DNA sequence variation in a combined 809 bp segment of the mtDNA genome from 66 individuals from the last six breeding regions showed relatively low levels of intraspecific sequence diversity (π = 0.32%) but significant differences in the regional distribution of 11 haplotypes (ΦST = 0.49). Despite their exceptional potential for dispersal, a complete and long‐term historical separation between the populations from the Iberian Peninsula (Spain) and mainland Europe (Hungary, Slovakia, Germany, and Russia) was demonstrated. Divergence between populations based on a 3‐bp insertion–deletion polymorphism within the intron region of the nuclear CHD‐Z gene was geographically concordant with the primary subdivision identified within the mtDNA sequences. Inferred aspects of phylogeography were used to formulate conservation recommendations for this endangered species.

A HEPATOZOON SPECIES GENETICALLY DISTINCT FROM H. CANIS INFECTING SPOTTED HYENAS IN THE SERENGETI ECOSYSTEM, TANZANIA

Health monitoring of spotted hyenas (Crocuta crocuta) in the Serengeti ecosystem, Tanzania, revealed Hepatozoon infection in all of 11 immature individuals examined following death from natural causes. Hepatozoon infection was probably an important factor contributing to mortality in two cases that exhibited clinical signs of ataxia, lethargy, ocular discharge, retching, and labored breathing before death. Whether Hepatozoon infection contributed to six deaths from fire, probable lion predation and unknown causes could not be determined. Four deaths from infanticide and starvation were unlikely to be associated with Hepatozoon infection. Histologic examination revealed lung tissue infected with cyst-like structures containing protozoan stages in all eight cases examined and interstitial pneumonia in most cases. Systemic spread of infection to several organs was found in three cases. Alignment of a 426 bp sequence from the parasites 18s rRNA gene revealed a Hepatozoon species identical to that recently described from two domestic cats in Spain and only 7 bp substitutions when a 853 bp sequence was aligned to this cat Hepatozoon species. Previous reports of infection of wild carnivores in eastern and southern Africa with an unspecified Hepatozoon species similar in appearance to H. canis may have involved the species described in this study.

Detection of a Newly Described Pestivirus of Pyrenean Chamois (Rupicapra pyrenaica pyrenaica) in France

A pestivirus was detected and characterized in chamois (Rupicapra pyrenaica pyrenaica) originating from the French part of the Pyrenees. Phylogenetic analysis of the pestivirus was done on the basis of a fragment from the 5′ noncoding region including 22 published nucleotide sequences of different pestivirus strains. Our strain was grouped within the clade of border disease viruses (BDV). However, it had an intermediate position between clade BDV and classical swine fever viruses representing a basal position to BDV strains of domestic sheep. Our strain was grouped as a sister unit to a novel pestivirus (Chamois-1) recently described from chamois in Spain. Therefore, we postulate that this virus occurs in the entire population of Pyrenean chamois. On the basis of the phylogenetic grouping of this isolate, a postulated cross-species transmission of pestivirus from domestic sheep to chamois via shared pastures seems to be unlikely

Great bustard population structure in central Spain: concordant results from genetic analysis and dispersal study

We found significant sex differences in the mtDNA genetic structure and dispersal patterns of great bustards in a population of 11 breeding groups, ‘leks’, in central Spain. The analysis of genetic distances showed that the female population was divided into three groups of leks separated by ca. 50 km, whereas male haplotypes were randomly distributed among leks. Genetic distances among pairs of leks were positively correlated with geographical distances in females but not in males. While female haplotype distributions were homogeneous among leks at close distances, differences in male genetic structure were highly variable even between two close leks. These results from genetic analyses were concordant with those from a radiotracking study on natal dispersal. Natal dispersal distances were higher in males than in females. Also, the frequency of movement of a female between two leks was positively correlated with their genetic affinity and geographical proximity. In males, the frequency of movement was correlated with geographical proximity but not with genetic affinity. Males dispersed among genetically unrelated leks, contributing to keep nuclear genetic diversity in the population, whereas females tended to be philopatric. These results suggest that isolation–by–distance influences the distribution of maternal lineages at a regional level.

Genetic variation across the current range of the Asian houbara bustard (Chlamydotis undulata macqueenii)

The houbara bustard (Chlamydotisundulata), the main quarry for Arab falconry,is currently threatened by excessive huntingand poaching as well as by habitat loss andfragmentation. We have investigated the geneticdiversity, population structure and demographichistory of houbara bustards across theirgeographical range by analyzing mitochondrial(mt)DNA sequences (a 370 bp fragment of controlregion I and a 264 bp fragment of thecytochrome b gene) and 4 microsatelliteloci in 74 individuals sampled from the CanaryIslands to China. Both markers revealed low tomoderate diversity that could be partitionedinto two monophyletic groups or evolutionarysignificant units belonging to the NorthAfrican (C. u. undulata) and Asian (C. u. macqueenii) subspecies. A history ofrelatively recent population growth (∼35,000years ago) accompanied by range expansion isthe most likely demographic scenario for theAsian subspecies. In addition, Macqueensbustards are able to disperse efficiently overbroad areas, which is consistent with ourinference of weak phylogeographic structure(global FST = 0.20 and 0.04 formtDNA and microsatellites, respectively) andhigh levels of homogenizing gene flow on widegeographical scales. We therefore suggest thatmanagement actions should focus on maintainingmigratory connectivity between breeding andnon-breeding areas.

Comparison of glycoprotein B (gB) variants of the elephant endotheliotropic herpesvirus (EEHV) isolated from Asian elephants (Elephas maximus)

The recently described elephant endotheliotropic herpesviruses (EEHV) have been associated with the deaths of numerous captive elephants. A proposed tool for the detection of EEHV infection in elephants is the PCR-based screening for EEHV-DNA in whole blood samples. Unfortunately, this detection method has only been successful in post-mortem analyses or in animals already displaying clinical signs of EEHV disease, thus rendering this method unsuitable for identification of carrier elephants. Here, we focus on glycoprotein B (gB) for serologic assay development, since gB is an envelope protein known to induce a neutralising antibody response in other herpesvirus infections. We sequenced the entire gB gene from five Asian elephants with EEHV, representing four different gB variants. Computer-aided methods were used to predict functionally important regions within EEHVgB. An extra-cytoplasmic region of 153 amino acids was predicted to be under positive selection and may potentially contain antigenic determinants that will be useful for future serologic assay development.

Fertility of a spontaneous hexaploid male Siberian sturgeon, Acipenser baerii

BackgroundEvolution of sturgeons and paddlefishes (order Acipenseriformes) is inherently connected with polyploidization events which resulted in differentiation of ploidy levels and chromosome numbers of present acipenseriform species. Moreover, allopolyploidization as well as autopolyploidization seems to be an ongoing process in these fishes and individuals with abnormal ploidy levels were occasionally observed within sturgeon populations. Here, we reported occurrence of Siberian sturgeon (Acipenser baerii) male with abnormal ploidy level for this species, accessed its ploidy level and chromosome number and investigate its potential sterility or fertility in comparison with normal individuals of sterlet (A. ruthenus), Russian sturgeon (A. gueldenstaedtii) and Siberian sturgeon (A. baerii).ResultsAcipenser ruthenus possessed 120 chromosomes, exhibiting recent diploidy (2n), A. gueldenstaedtii and A. baerii had ~245 chromosomes representing recent tetraploidy (4n), and A. baerii male with abnormal ploidy level had ~ 368 chromosomes, indicating recent hexaploidy (6n). Genealogy assessed from the mtDNA control region did not reveal genome markers of other sturgeon species and this individual was supposed to originate from spontaneous 1.5 fold increment in number of chromosome sets with respect to the number most frequently found in nature for this species. Following hormone stimulation, the spontaneous hexaploid male produced normal sperm with ability for fertilization. Fertilization of A. baerii and A. gueldenstaedtii ova from normal 4n level females with sperm of the hexaploid male produced viable, non-malformed pentaploid (5n) progeny with a ploidy level intermediate to those of the parents.ConclusionThis study firstly described occurrence of hexaploid individual of A. baerii and confirmed its autopolyploid origin. In addition to that, the first detailed evidence about fertility of spontaneous hexaploid sturgeon was provided. If 1.5 fold increment in number of chromosome sets occurring in diploids, resulted triploids possess odd number of chromosome sets causing their sterility or subfertility due to interference of gametogenesis. In contrast, 1.5 fold increment in number of chromosome sets in naturally tetraploid A. baerii resulted in even number of chromosome sets and therefore in fertility of the hexaploid specimen under study.

New variants of european brown hare syndrome virus strains in free-ranging European brown hares (Lepus europaeus) from Slovakia

Investigations regarding European brown hare syndrome virus (EBHSV) in European brown hares (Lepus europaeus) in Slovakia were undertaken in order to detect the possible presence of EBHSV and to evaluate its phylogenetic position. Liver and/or serum samples were obtained from 135 European brown hares shot by hunters in eight regional hunting areas. From 36 animals corresponding liver and serum samples were available; from the remaining 49 and 50 animals only liver or serum samples were examined, respectively. Samples were tested for antibodies against EBHSV and for viral RNA by reverse transcriptase–polymerase chain reaction (RT-PCR) and RT-PCR products were subsequently sequenced. Additionally, matrilinear hare haplotypes were analyzed in order to detect potential familial susceptibility to EBHSV. Sixty-three of 86 sera contained antibodies against EBHSV, whereas 15 of 85 liver samples were PCR positive. Of the latter, 14 were sequenced, revealing three new strains of EBHSV. Fifteen different matrilinear haplotypes were identified, but no correlation was found between haplotype and susceptibility to EBHSV infection. Our findings confirmed the existence of EBHSV in Slovakia and reinforce the need for determining EBHSV status when importing hares for restocking.