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C Schlötterer

Publications and source records attributed to C Schlötterer.

At least 19 recordsLinked to original sources
PubMed2004

Non-African origin of a local beneficial mutation in D. melanogaster.

It is well understood that the out-of-Africa habitat expansion of D. melanogaster was associated with the fixation of many beneficial mutations. Nevertheless, it is not clear yet whether these beneficial mutations segregated already in Africa or originated outside of Africa. In this article, we describe an ongoing selective sweep specific to one European population. One microsatellite allele has increased in a population from The Netherlands to a frequency of 18%, whereas it is virtually absent in 12 other European populations. The selective sweep resulted in a genomic region of more than 600 kb that is identical by descent. This is probably the first evidence of a beneficial mutation that has arisen outside of Africa and has resulted in a selective sweep localized in a population from The Netherlands.

Adaptation, Biological↗
PubMed2004

QTL analysis of variation in male courtship song characters in Drosophila virilis.

We have used a quantitative trait locus (QTL) mapping approach to study the genetic basis of differences between two Drosophila virilis strains representing extreme phenotypes in two song characters, the number of pulses in a pulse train (PN) and the length of a pulse train (PTL). Variation in these characters among 520 F2 males was studied by single-marker analysis and composite interval mapping (CIM) using a recombination linkage map constructed for 26 microsatellite markers. In single-marker analysis, two adjacent microsatellite markers on the third chromosome, msat19 and vir84 explained 13.8 and 12.4% of the variation in PN and 9.9 and 6.5% of the variation in PTL, respectively. CIM analysis revealed significant QTLs affecting PN, located on the X and the second, third and fourth chromosome of D. virilis, while variation in PTL was attributable to QTLs located only on the third chromosome.

Animals↗
PubMed2004

A multilocus microsatellite phylogeny of the Drosophila virilis group.

We used a set of 48 polymorphic microsatellites derived from Drosophila virilis to infer phylogenetic relationships in the D. virilis clade. Consistent with previous studies, D. virilis and D. lummei were the most basal species of the group. Within the D. montana phylad, the phylogenetic relationship could not be resolved. Special attention was given to the differentiation between D. americana texana, D. americana americana and D. novamexicana. Significant differences between these three groups were detected by F(ST) analyses. Similarly, a model-based clustering method for multilocus genotype data also provided strong support for the presence of three differentiated groups. This genome-wide differentiation between D. americana texana and D. americana americana contrasts with previous analyses based on DNA sequence data.

Animals↗
PubMed2004

An analysis of genetic differentiation among assortatively mating Drosophila melanogaster in Zimbabwe.

African Drosophila melanogaster populations, and those from Zimbabwe in particular, have attracted much interest recently. African flies differ genetically from 'cosmopolitan' populations and were found to exhibit discriminative mating behaviour against individuals from 'cosmopolitan' populations. It has therefore been proposed that Zimbabwean and some other African populations are in an 'incipient stage of speciation'. However, whether the mating behaviour is an effective barrier against gene flow from other populations, and whether intra-population genetic differentiation has already evolved in sympatry is not known. Here, we took a population-based approach to test whether the well-characterized mating type differences have resulted in a genome-wide differentiation at the population level. Using 122 polymorphic microsatellite loci mapping to the third chromosome, we demonstrate a significant genetic differentiation between Zimbabwean flies differing in their mating behaviour. We also provide evidence to suggest that this difference is unlikely to be attributable to population structure within Zimbabwe. However, the analysis of individual microsatellite loci did not indicate more loci differentiating these two groups than expected by chance. Our data suggest that the 'Z'-'M' mating behaviour is strong enough to result in a small but significant genetic differentiation. Thus, future studies based on a larger population sample of flies characterized for their mating behaviour and using more markers are expected to provide more information on the genetic basis of the mating traits in the Zimbabwe flies.

Animals↗
PubMed2003

Genetic differentiation between American and European Drosophila melanogaster populations could be attributed to admixture of African alleles.

A total of 48 polymorphic microsatellite loci were characterized in 13 Drosophila melanogaster populations originating from Europe, America, and Africa. Consistent with previous results, the African D. melanogaster populations were the most differentiated populations and harbored most variation. Despite an overall similarity, American and European populations were significantly differentiated. Interestingly, genetic distances based on the proportion of shared alleles as well as FST values suggested that the American D. melanogaster populations are more closely related to the African populations than European ones are. We also detected a higher proportion of putative African alleles in the American populations, indicating recent admixture of African alleles on the American continent.

Africa↗
PubMed2003

A microsatellite variability screen for positive selection associated with the "out of Africa" habitat expansion of Drosophila melanogaster.

We report a "hitchhiking mapping" study in D. melanogaster, which searches for genomic regions with reduced variability. The study's aim was to identify selective sweeps associated with the "out of Africa" habitat expansion. We scanned 103 microsatellites on chromosome 3 and 102 microsatellites on the X chromosome for reduced variability in non-African populations. When the chromosomes were analyzed separately, the number of loci with a significant reduction in variability only slightly exceeded the expectation under neutrality--six loci on the third chromosome and four loci on the X chromosome. However, non-African populations also have a more pronounced average loss in variability on the X chromosomes as compared to the third chromosome, which suggests the action of selection. Therefore, comparing the X chromosome to the autosome yields a higher number of significantly reduced loci. However, a more pronounced loss of variability on the X chromosome may be caused by demographic events rather than by natural selection. We therefore explored a range of demographic scenarios and found that some of these captured most, but not all aspects of our data. More theoretical work is needed to evaluate how demographic events might differentially affect X chromosomes and autosomes and to estimate the most likely scenario associated with the out of Africa expansion of D. melanogaster.

Animals↗
PubMed2002

Complex patterns of colonization and refugia revealed for European grayling Thymallus thymallus, based on complete sequencing of the mitochondrial DNA control region.

The complete mitochondrial DNA (mtDNA) control region (1043 base pairs) and 162-bp of flanking transfer RNA genes were sequenced in 316 European grayling, Thymallus thymallus, from 44 populations throughout the Western European range of the species. A total of 58 haplotypes were revealed with pairwise divergence ranging from 0.001 to 0.038. An inferred intraspecific phylogenetic tree revealed two well-supported clades within the Danube basin, one highly divergent clade in the Adriatic basin, and one large, diverse group representing most other populations. A deeply divergent haplotype fixed in the Loire basin in central France, more groups of haplotypes from distinct Danubian tributaries, and a relatively ancestral haplotype fixed in former tributaries of the Elbe in Denmark all suggest a complex pattern of interglacial and postglacial expansions originating from disjunct refugia throughout central Europe. Despite some evidence of human-mediated stock transfers, parsimony-network-based nested-clade analysis (NCA) supported specific inferences relating to corridors of postglacial expansion such as the lower Rhine (Moselle) and Elbe systems (Danish populations) serving as sources for expansion into the Baltic to the north as well as the upper Rhine and Danube to the south; and specific Rhine populations (Doller, Orbe and Reuss) serving as sources for colonization of the Rhone. The multiple divergent clades representing populations in the upper Danube, as well as the deeply divergent haplotypes found in the Adriatic and Loire basins (> 5% divergence from Asian outgroups) support the theory that European grayling have had a long history in Western Europe, pre-dating Pleistocene glacial cycles. The patterns of mtDNA divergence shown here support a perspective of rich inter- and intrabasin genetic diversity that should be protected from current trends to translocate brood stocks for rearing and release in response to declining populations, especially in southern European basins.

Animals↗
PubMed2002

Chromosomal patterns of microsatellite variability contrast sharply in African and non-African populations of Drosophila melanogaster.

Levels of neutral variation are influenced by background selection and hitchhiking. The relative contribution of these evolutionary forces to the distribution of neutral variation is still the subject of ongoing debates. Using 133 microsatellites, we determined levels of variability on X chromosomes and autosomes in African and non-African D. melanogaster populations. In the ancestral African populations microsatellite variability was higher on X chromosomes than on autosomes. In non-African populations X-linked polymorphism is significantly more reduced than autosomal variation. In non-African populations we observed a significant positive correlation between X chromosomal polymorphism and recombination rate. These results are consistent with the interpretation that background selection shapes levels of neutral variability in the ancestral populations, while the pattern in derived populations is determined by multiple selective sweeps during the colonization process. Further research, however, is required to investigate the influence of inversion polymorphisms and unequal sex ratios.

Africa↗
PubMed2001

Genealogical inference of closely related species based on microsatellites.

Despite their unmatched popularity in many research areas, microsatellites have not yet become a major tool for the inference of genealogical relationships of closely related species. Recent studies have successfully extended the repertoire of microsatellite analysis beyond population genetics and demonstrate that phylogenetic relationships of closely related species can be inferred accurately with fewer loci than previously assumed.

Animals↗
PubMed2001

Haplotype (mtDNA) diversity of brown trout Salmo trutta in tributaries of the Austrian Danube: massive introgression of Atlantic basin fish--by man or nature?

Mitochondrial haplotype diversity in 27 populations of brown trout, Salmo trutta L., in Austria was investigated by sequencing the 5' end of the mitochondrial DNA (mtDNA) control region. Although all populations are within the Danube drainage, 44% of all individuals carried Atlantic basin haplotypes. It is argued that the presence of these haplotypes in Austria primarily reflects introgression stemming from the stocking of hatchery-reared fish. However, several lines of evidence suggest that some natural colonization from Atlantic lineages may have contributed to the present haplotype diversity. Nonetheless, the more diverse Danubian clade is represented by regionally distinct haplotype diversity that should be protected from the continued introduction of domesticated strains of exogenous fish

Animals↗
PubMed2001

Microsatellite variation in natural Drosophila melanogaster populations from New South Wales (Australia) and Tasmania.

Microsatellite variation was studied at 48 microsatellite loci in 10 Drosophila melanogaster populations to investigate the population structure on the Australian east coast. Low, but statistically significant population differentiation was observed among most populations. The populations on the Australian mainland did not show evidence for isolation by distance. We conclude that the population structure of D. melanogaster on the Australian mainland is probably the result of a shared history (recent colonization). The observed differences between local D. melanogaster populations probably reflect variation in effective population sizes rather than patterns of gene flow. Two populations from Tasmania were more differentiated from the Australian mainland than a population from Israel, raising the question whether they are derived from the Australian mainland or colonized from a different source population.

Animals↗
PubMed2001

Three divergent rDNA clusters predate the species divergence in Quercus petraea (Matt.) Liebl. and Quercus robur L.

Quercus petraea and Quercus robur are two closely related oak species that frequently hybridize. We sequenced 70 clones containing the 5.8S and ITS2 regions of ribosomal DNA (rDNA) from these two species and did not detect a species-specific difference. Surprisingly, three divergent (up to 12.6%) rDNA families were identified in both species, indicating that they predate the speciation event. Despite a large between-rDNA-families divergence, rDNA sequences were very similar within families, suggesting ongoing concerted evolution. Expression analysis, relative-rate tests, and mutation spectrum analyses indicated that only a single rDNA family is functional. We propose that past hybridization events, combined with nucleolar dominance, were the evolutionary processes underlying the contemporary rDNA variability in Q. petraea and Q. robur.

Base Sequence↗
PubMed2001

Trichome distribution in Arabidopsis thaliana and its close relative Arabidopsis lyrata: molecular analysis of the candidate gene GLABROUS1.

GLABROUS1 (GL1) belongs to the large family of MYB transcription factors and is known to play a central role in trichome initiation. We studied trichome distribution and the molecular variation of GL1 in 28 A. thaliana accessions. Trichome density on rosette leaves was highly variable among those accessions. On the molecular level, we detected substantial sequence variation in a 3-kb fragment which included the complete coding region of the GL1 locus (pi = 0.01). Phylogenetic analysis of GL1 indicates the presence of two diverged clades among 28 accessions. Using ANOVA, we show that the phenotypic variation in trichome density cannot be explained by the sequence divergence between the two phylogenetic lineages. Sequence analysis of wild-type Arabidopsis thaliana and Arabidopsis lyrata accessions indicates that all amino acid substitutions are located outside of the conserved helix-turn-helix DNA-binding domains R2 and R3. Using plants of A. thaliana and A. lyrata with either naturally occurring or ethyl methane sulfonate--induced glabrous phenotypes, we demonstrate that the last 14 C-terminal amino acids of the GL1 gene have no major impact on the initiation of trichomes.

Analysis of Variance↗
PubMed2000

Molecular phylogeny of European muroid rodents based on complete cytochrome b sequences.

Phylogenetic relationships among 18 species of mainly European muroid rodents that belong to three subfamilies were estimated using complete sequences of the mitochondrial cytochrome b gene. The inferred monophyly of the subfamilies Murinae (mice and rats) and Arvicolinae (voles, lemmings, and muskrats) is in agreement with previous studies. Within the Murinae, the morphology-based division of the genus Apodemus into three subgenera is supported by these DNA sequence data. The relationships among the different genera of the Murinae were generally poorly resolved, and the relationships of Micromys and Acomys to the other murine genera remained unresolved. Within the subfamily Arvicolinae, the relations of the genera Arvicola, Clethrionomys, and Microtus remained tentative with our data. However, within the Microtus group, there is a good molecular support for the phylogenetic relationships. These findings suggest that the origin of the different murine and arvicoline lineages was rapid, indicating an adaptive radiation with fast speciation.

Animals↗
PubMed2000

Evolutionary dynamics of microsatellite DNA.

Within the past decade microsatellites have developed into one of the most popular genetic markers. Despite the widespread use of microsatellite analysis, an integral picture of the mutational dynamics of microsatellite DNA is just beginning to emerge. Here, I review both generally agreed and controversial results about the mutational dynamics of microsatellite DNA. Microsatellites are short DNA sequence stretches in which a motif of one to six bases is tandemly repeated. It has been known for some time that these sequences can differ in repeat number among individuals. With the advent of polymerase chain reaction (PCR) technology this property of microsatellite DNA was converted into a highly versatile genetic marker (Litt and Luty 1989; Tautz 1989; Weber and May 1989). Polymerase chain reaction products of different length can be amplified with primers flanking the variable microsatellite region. Due to the availability of high-throughput capillary sequencers or mass spectrography the sizing of alleles is no longer a bottleneck in microsatellite analysis. The almost random distribution of microsatellites and their high level of polymorphism greatly facilitated the construction of genetic maps (Dietrich et al. 1994; Dib et al. 1996) and enabled subsequent positional cloning of several genes. Almost at the same time, microsatellites were established as the marker of choice for the identification of individuals and paternity testing. The high sensitivity of PCR-based microsatellite analysis was not only of great benefit for forensics, but opened completely new research areas, such as the analysis of samples with limited DNA amounts (e.g., many social insects) or degraded DNA (e.g., feces, museum material) (Schlötterer and Pemberton 1998). More recently, microsatellite analysis has also been employed in population genetics (Goldstein and Schlötterer 1999). Compared with allozymes, microsatellites offer the advantage that, in principle, several thousand potentially polymorphic markers are available. Nevertheless, the application of microsatellites to population genetic questions requires a more detailed understanding of the mutation processes of microsatellite DNA as the evolutionary time frames covered in population genetics are often too long to allow novel microsatellite mutations to be ignored. Additional interest in the evolution of microsatellite DNA comes from the discovery that trinucleotide repeats, a special class of microsatellites, are involved in human neurodegenerative diseases (e.g., fragile X and Huntington's disease). A detailed understanding of the processes underlying microsatellite instability is therefore an important contribution toward a better understanding of these human neurodegenerative diseases.

Animals↗
PubMed2000

Microsatellite analysis reveals substantial genetic differentiation between contemporary New World and Old World Holstein Friesian populations.

Genotypic data from 39 microsatellite loci typed in 211 animals were used to assess the genetic differentiation between Old World and New World Holstein Friesian cattle populations. Gene diversities were similar in all five Holstein Friesian populations surveyed, ranging from 0.43 to 0.48. A tree of individuals based on the proportion of shared alleles indicated a clear distinction between Old World and New World Holstein Friesian populations. Similarly, genetic differentiation between populations, as measured by FST, was highly significant. Using the split decomposition method, we were able to visualize the significant introgression of New World Holstein Friesian into European Holstein Friesian populations.

Alleles↗
PubMed2000

Microsatellite analysis indicates genetic differentiation of the neo-sex chromosomes in Drosophila americana americana.

The neo-sex chromosomes of Drosophila americana americana were formed by a centric fusion between the autosomal element B and the X chromosome. Previous work has shown that the neo-Y chromosome is not degenerated genetically and that there is no evidence for genetic differentiation between neo-X and neo-Y chromosomes at the sequence level. To further address the genetic differentiation between the neo-sex chromosomes, microsatellites mapping to the neo-sex chromosome of D. a. americana were isolated. Microsatellite analysis indicated a highly significant differentiation between D. a. americana and D. a. texana as well as between the neo-X and neo-Y chromosomes in D. a. americana. Nevertheless, levels of variability were similar among the neo-sex chromosomes, indicating a very recent origin.

Animals↗