Biology subjects

Wellenreuther, M.

Publications and source records attributed to Wellenreuther, M..

5 recordsLinked to original sources

bioRxiv2018

Domestication and temperature modulate gene expression signatures and growth in the Australasian snapper Chrysophrys auratus

ABSTRACT\n\nIdentifying genes and pathways involved in domestication is critical to understand how species change in response to human-induced selection pressures. We experimentally manipulated temperature conditions for F1-hatchery and wild Australasian snapper (Chrysophrys auratus) for 18 days and measured differences in growth, white muscle RNA transcription and haematological blood parameters. Over 2.2 Gb paired-end reads were assembled de novo for a total set of 33,017 transcripts (N50 = 2,804). We found pronounced growth and gene expression differences between wild and domesticated individuals related to global developmental and immune pathways. Temperature modulated growth responses were linked to major pathways affecting metabolism, cell regulation and signalling. This study is the first step towards gaining an understanding of the changes occurring in the early stages of domestication, and the mechanisms underlying thermal adaptation and associated growth in poikilothermic vertebrates. Our study further provides the first transcriptome resources for studying biological questions in this non-model fish species.

evolutionary biology↗

bioRxiv2018

High-density linkage map and QTLs for growth in snapper (Chrysophrys auratus)

Characterizing the genetic variation underlying phenotypic traits is a central objective in biological research. This research has been hampered in the past by the limited genomic resources available for most non-model species. However, recent advances in sequencing technology and related genotyping methods are rapidly changing this. Here we report the use of genome-wide SNP data from the ecologically and commercially important marine fish species Chrysophrys auratus (snapper) to 1) construct the first linkage map for this species, 2) scan for growth QTLs, and 3) search for candidate genes in the surrounding QTL regions. The newly constructed linkage map contained ~11K SNP markers and is the densest map to date in the fish family Sparidae. Comparisons with available genome scaffolds indicated that overall marker placement was strongly correlated between the scaffolds and linkage map (R = 0.7), but at fine scales (< 5 cM) there were some precision limitations. Of the 24 linkage groups, which reflect the 24 chromosomes of this species, three were found to contain QTLs with genome-wide significance for growth-related traits. A scan for 13 known candidate growth genes located the genes for growth hormone, parvalbumin, and myogenin within 13.2, 2.6, and 5.0 cM of these genome-wide significant QTLs, respectively. The linkage map and QTLs found in this study will advance the investigation of genome structure and selective breeding in snapper.

evolutionary biology↗

bioRxiv2018

Genetic divergence and phenotypic plasticity contribute to variation in cuticular hydrocarbons in the seaweed fly C. frigida

Male sexual signals facilitate female choice and thereby reduce mating costs. The seaweed fly Coelopa frigida is characterized by intense sexual conflict, yet it is unclear which traits are under sexual selection. In this study, we investigated phenotypic and genetic variation in cuticular hydrocarbons (CHCs) in C. frigida for the first time. CHCs are ubiquitous in insects and they act as sex pheromone in many dipterans. We characterized CHCs and found that composition was affected by both genetic (sex and population origin) and environmental (larval diet) factors. We identified general shifts in CHC chemistry as well as individual compounds and found that the methylated compounds, mean chain length, proportion of alkenes, and normalized total CHCs differed between sexes and populations. We combined this data with whole genome resequencing data to examine the genetic underpinnings of these differences. We identified 11 genes related to CHC synthesis and found population level outlier SNPs in 5 that are concordant with phenotypic differences. Together these results reveal that the CHC composition of C. frigida is dynamic, strongly affected by the larval environment, and likely under natural and/or sexual selection.

evolutionary biology↗

bioRxiv2018

Inversion frequencies and phenotypic effects are modulated by the environment

Understanding how environmental variation drives phenotypic diversification within species is a major objective in evolutionary biology. The seaweed fly Coelopa frigida provides an excellent model for the study of genetically driven phenotypes because it carries an /{beta} inversion polymorphism that affects body size. Coelopa frigida inhabits highly variable beds of decomposing seaweed on the coast in Scandinavia thus providing a suitable test ground to investigate the genetic effects of substrate on both the frequency of the inversion (directional selection) and on the phenotype (genotype x environment effects). Here we use a reciprocal transplant experiment to test the effect of the /{beta} inversion on body size traits and development time across four suitable natural breeding substrates from the clinal distribution. We show that while development time is unaffected by GxE effects, both the frequency of the inversion and the relative phenotypic effects of the inversion on body size differ between population x substrate combinations. This indicates that the environment modulates the fitness as well as the phenotypic effects of the inversion karyotypes. It further suggests that the inversion may have accumulated qualitatively different mutations in different populations that interact with the environment. Together our results are consistent with the idea that the inversion in C. frigida likely evolves via a combination of local mutation, GxE effects, and differential fitness of inversion karyotypes in heterogeneous environments.

evolutionary biology↗

bioRxiv2018

Karyotype-environment associations support a role for a chromosomal inversion in local adaptation among North American populations of the seaweed fly Coelopa frigida

Large chromosomal rearrangements are thought to facilitate adaptation to heterogeneous environments by limiting genomic recombination. Indeed, inversions have been implicated in adaptation along environmental clines and in ecotype specialisation. Here, we combine classical ecological studies and population genetics to investigate an inversion polymorphism previously documented in Europe among natural populations of the seaweed fly Coelopa frigida along a latitudinal cline in North America. We test if the inversion is present in North America and polymorphic, assess which environmental conditions modulate the inversion karyotype frequencies, and document the relationship between inversion karyotype and adult size. We sampled nearly 2,000 flies from 20 populations along several environmental gradients to quantify associations of inversion frequencies to heterogeneous environmental variables. Genotyping and phenotyping showed a widespread and conserved inversion polymorphism between Europe and America. Variation in inversion frequency was significantly associated with environmental factors, with parallel patterns between continents, indicating that the inversion may play a role in local adaptation. The three karyotypes of the inversion are differently favoured across micro-habitats and represent life-history strategies likely maintained by the collective action of several mechanisms of balancing selection. Our study adds to the mounting evidence that inversions are facilitators of adaptation and enhance within-species diversity.

evolutionary biology↗