Hedwig Sauer-Gürth

The use of (GACA)4 PCR to sex Old World vultures (Aves: Accipitridae)

A PCR method was developed employing a single primer (GACA)4 to sex Black vultures (Aegypius monachus), Lappet‐faced vultures (Torgos tracheliotus), and Griffon vultures (Gyps fulvus). Using the (GACA)4 primer several PCR products were generated. One or more PCR products displayed a sex‐specific pattern, i.e. they were only present in females (probably corresponding to repetitive DNA on the W chromosome) but absent in males. The sex ratio of 85 Griffon vultures from Spain was almost 1.

Biosynthesis of pseudoisoeugenols in tissue cultures ofPimpinella anisum

The genusPimpinella contains pseudoisoeugenols, phenylpropanoids with a rare 2,5-dioxy substitution pattern on the phenyl ring. To study the biosynthesis of these compounds, we set up a leaf-differentiating tissue culture ofPimpinella anisum. These cultures mainly produce epoxy-pseudoisoeugenol-(2-methylbutyrate). To corroborate the biosynthetic pathway of epoxy-pseudoisoeugenol-(2-methylbutyrate) as proposed on the basis of investigations with13C/14C-labelled precursors, the key steps of the pathway were investigated at an enzyme level. Experiments with cell-free homogenates clearly revealed that L-phenylalanine is converted to (E)-cinnamic acid by phenylalanine ammonia lyase and that (E)-cinnamic acid is converted top-coumaric acid by cinnamic acid 4-hydroxylase. L-2-aminooxy-3-phenylpropionic acid, an analogue of L-phenylalanine, inhibited the incorporation of L-[3′-13C]phenylalanine into epoxy-pseudoisoeugenol-(2-methylbutyrate). Up to 2% of the precursor DL-[3′-13C]phenyllactate was incorporated into epoxy-pseudoisoeugenol-(2-methylbutyrate). Inhibition experiments with oxalacetic acid clearly showed that cinnamic acid is not formed by dehydration of phenyllactic acid in this leaf-differentiating tissue culture ofP. anisum.

Allozyme and DNA sequence data support speciation of Northern and Southern populations of silver catfish, Schilbe intermedius (Rüppel, 1832)

Patterns of genetic variation in Schilbe intermedius were investigated due to morphological differences and taxonomic uncertainties regarding the Southern African schilbeids. A total of three populations, two Southern populations representing the former Eutropius depressirostris and a Northern population representing S. mystus, were electrophoretically analysed to determine the extent of genetic differentiation among these populations. The Northern and Southern populations were fixed for different alleles at the G3PDH-2 protein coding locus and allozyme differentiation between populations, using the 0.95 criterion, were also encountered at the PGDH-2 locus. Genetic distance values indicate greater genetic differentiation between the Northern and Southern populations compared to the two Southern populations. DNA sequence analysis of 900-1000 nucleotides of the cytochrome b gene revealed distances of 3.2-3.5% between the Schilbe/Eutropius complex. This finding, together with ingroup and outgroup analysis of evolutionary relationships, is congruent with the results from the electrophoretic analysis of the taxa. Sufficient differentiation exist between the Northern and Southern populations to regard them as distinct species.

Characterization of a de novo assembled transcriptome of the Common Blackbird (Turdus merula)

Background In recent years, next generation high throughput sequencing technologies have proven to be useful tools for investigations concerning the genomics or transcriptomics also of non-model species. Consequently, ornithologists have adopted these technologies and the respective bioinformatics tools to survey the genomes and transcriptomes of a few avian non-model species. The Common Blackbird is one of the most common bird species living in European cities, which has successfully colonized urban areas and for which no reference genome or transcriptome is publicly available. However, to target questions like genome wide gene expression analysis, a reference genome or transcriptome is needed. Methods Therefore, in this study two Common Blackbirds were sacrificed, their mRNA was isolated and analyzed by RNA-Seq to de novo assemble a transcriptome and characterize it. Illumina reads (125 bp paired-end) and a Velvet/Oases pipeline led to 162,158 transcripts. For the annotation (using Blast+), an unfiltered protein database was used. SNPs were identified using SAMtools and BCFtools. Furthermore, mRNA from three single tissues (brain, heart and liver) of the same two Common Blackbirds were sequenced by Illumina (75 bp single-end reads). The draft transcriptome and the three single tissues were compared by their BLAST hits with the package VennDiagram in R. Results Following the annotation against protein databases, we found evidence for 15,580 genes in the transcriptome (all well characterized hits after annotation). On 18% of the assembled transcripts, 144,742 SNPs were identified which are, consequently, 0.09% of all nucleotides in the assembled transcriptome. In the transcriptome and in the single tissues (brain, heart and liver), 10,182 shared genes were found. Discussion Using a next-generation technology and bioinformatics tools, we made a first step towards the genomic investigation of the Common Blackbird. The de novo assembled transcriptome is usable for downstream analyses such as differential gene expression analysis and SNP identification. This study shows the importance of the approach to sequence single tissues to understand functions of tissues, proteins and the phenotype.

Pre-Quaternary divergence and subsequent radiation explain longitudinal patterns of genetic and morphological variation in the striped skink, Heremites vittatus

BackgroundMany animal and plant species in the Middle East and northern Africa have a predominantly longitudinal distribution, extending from Iran and Turkey along the eastern Mediterranean coast into northern Africa. These species are potentially characterized by longitudinal patterns of biological diversity, but little is known about the underlying biogeographic mechanisms and evolutionary timescales. We examined these questions in the striped skink, Heremites vittatus, one such species with a roughly longitudinal distribution across the Middle East and northern Africa, by analyzing range-wide patterns of mitochondrial DNA (mtDNA) sequence and multi-trait morphological variation.ResultsThe striped skink exhibits a basic longitudinal organization of mtDNA diversity, with three major mitochondrial lineages inhabiting northern Africa, the eastern Mediterranean coast, and Turkey/Iran. Remarkably, these lineages are of pre-Quaternary origin, and are characterized by p-distances of 9–10%. In addition, within each of these lineages a more recent Quaternary genetic diversification was observed, as evidenced by deep subclades and high haplotype diversity especially in the Turkish/Iranian and eastern Mediterranean lineages. Consistent with the genetic variation, our morphological analysis revealed that the majority of morphological traits show significant mean differences between specimens from northern Africa, the eastern Mediterranean coast, and Turkey/Iran, suggesting lineage-specific trait evolution. In addition, a subset of traits exhibits clinal variation along the eastern Mediterranean coast, potentially indicating selection gradients at the geographic transition from northern Africa to Anatolia. The existence of allopatric, morphologically and genetically divergent lineages suggests that Heremites vittatus might represent a complex with several taxa.ConclusionsOur work demonstrates that early divergence events in the Pliocene, likely driven by both climatic and geological factors, established the longitudinal patterns and distribution of Heremites vittatus. Subsequent radiation during the Pleistocene generated the genetic and morphological diversity observed today. Our study provides further evidence that longitudinal diversity patterns and species distributions in the Middle East and northern Africa were shaped by complex evolutionary processes, involving the region’s intricate geological history, climatic oscillations, and the presence of the Sahara.

New Microsatellite Markers for the Common Tern (Sterna hirundo) Developed with 454 Shot-Gun Pyrosequencing

Long term studies, focusing on populationand socio-biology research, require the unequivocal identification of individuals. DNA studies with Short Tandem Repeats (STR loci) became a widespread tool in population genetics. We used the nextgeneration sequencing (NGS) approach with 454 shot-gun pyrosequencing to identify 13 new polymorphic STR loci for the Common Tern, Sterna hirundo. To enlarge the marker set we added two more loci originally developed for Black-legged Kittiwake (Rissa tridactyla) and Red-billed Gull (Chroicocephalus scopulinus) and arranged these 15 loci into three multiplex PCR panels for high throughput genotyping. Loci characterization demonstrated that our marker set is of high quality. A PIC value of about 0.67 and a power of exclusion value of 0.99 were reached. Deviation from Hardy-Weinberg expectations of some loci and low frequencies for null alleles are interpreted as a result of inbreeding and founder effect in the investigated tern colony. We used a test data set of this well-studied breeding colony of Common Tern at Banter Lake, Wilhelmshaven, Germany, to perform a parentage test. Parent-chick relationships, known from the social pedigree of that colony, were compared with genetically calculated ones. In order to test our markers and the used parentage program COLONY, we conducted six competing data sets with varying completeness of included parental genotypes. By including fully sampled parent pairs of known family assignment, results were correct for nest mates, single parents and parent pairs. Our marker set provides a powerful tool to investigate life-time reproductive success and other issues of population and socio-biology for Common Terns, e.g. in the aforementioned colony monitored for decades.