ESTs and EST-linked polymorphisms for genetic mapping and phylogenetic reconstruction in the guppy, Poecilia reticulata

<p>Abstract</p> <p>Background</p> <p>The guppy, <it>Poecilia reticulata</it>, is a well-known model organism for studying inheritance and variation of male ornamental traits as well as adaptation to different river habitats. However, genomic resources for studying this important model were not previously widely available.</p> <p>Results</p> <p>With the aim of generating molecular markers for genetic mapping of the guppy, cDNA libraries were constructed from embryos and different adult organs to generate expressed sequence tags (ESTs). About 18,000 ESTs were annotated according to BLASTN and BLASTX results and the sequence information from the 3' UTRs was exploited to generate PCR primers for re-sequencing of genomic DNA from different wild type strains. By comparison of EST-linked genomic sequences from at least four different ecotypes, about 1,700 polymorphisms were identified, representing about 400 distinct genes. Two interconnected MySQL databases were built to organize the ESTs and markers, respectively. A robust phylogeny of the guppy was reconstructed, based on 10 different nuclear genes.</p> <p>Conclusion</p> <p>Our EST and marker databases provide useful tools for genetic mapping and phylogenetic studies of the guppy.</p

Linkage Analysis Reveals the Independent Origin of Poeciliid Sex Chromosomes and a Case of Atypical Sex Inheritance in the Guppy (Poecilia reticulata)

Among different teleost fish species, diverse sex-determining mechanisms exist, including environmental and genetic sex determination, yet chromosomal sex determination with male heterogamety (XY) prevails. Different pairs of autosomes have evolved as sex chromosomes among species in the same genus without evidence for a master sex-determining locus being identical. Models for evolution of Y chromosomes predict that male-advantageous genes become linked to a sex-determining locus and suppressed recombination ensures their co-inheritance. In the guppy, Poecilia reticulata, a set of genes responsible for adult male ornaments are linked to the sex-determining locus on the incipient Y chromosome. We have identified >60 sex-linked molecular markers to generate a detailed map for the sex linkage group of the guppy and compared it with the syntenic autosome 12 of medaka. We mapped the sex-determining locus to the distal end of the sex chromosome. We report a sex-biased distribution of recombination events in female and male meiosis on sex chromosomes. In one mapping cross, we observed sex ratio and male phenotype deviations and propose an atypical mode of genetic sex inheritance as its basis

Synthesis of novel amino acid derivative of 7-AVCA

Abstract: In this study

Opsin gene duplication and diversification in the guppy, a model for sexual selection

Identification of genes that control variation in adaptive characters is a prerequisite for understanding the processes that drive sexual and natural selection. Male coloration and female colour perception play important roles in mate choice in the guppy (Poecilia reticulata), a model organism for studies of natural and sexual selection. We examined a potential source for the known variation in colour perception, by analysing genomic and complementary DNA sequences of genes that code for visual pigment proteins. We find high sequence variability, both within and between populations, and expanded copy number for long-wave sensitive (LWS) opsin genes. Alleles with non-synonymous changes that suggest dissimilar spectral tuning properties occur in the same population and even in the same individual, and the high frequency of non-synonymous substitutions argues for diversifying selection acting on these proteins. Therefore, variability in tuning amino acids is partitioned within individuals and populations of the guppy, in contrast to variability for LWS at higher taxonomic levels in cichlids, a second model system for differentiation owing to sexual selection. Since opsin variability parallels the extreme male colour polymorphism within guppy populations, we suggest that mate choice has been a major factor driving the coevolution of opsins and male ornaments in this species

Electricity from lignocellulosic substrates by thermophilic Geobacillus species

Abstract Given our vast lignocellulosic biomass reserves and the difficulty in bioprocessing them without expensive pretreatment and fuel separation steps, the conversion of lignocellulosic biomass directly into electricity would be beneficial. Here we report the previously unexplored capabilities of thermophilic Geobacillus sp. strain WSUCF1 to generate electricity directly from such complex substrates in microbial fuel cells. This process obviates the need for exogenous enzymes and redox mediator supplements. Cyclic voltammetry and chromatography studies revealed the electrochemical signatures of riboflavin molecules that reflect mediated electron transfer capabilities of strain WSUCF1. Proteomics and genomics analysis corroborated that WSUCF1 biofilms uses type-II NADH dehydrogenase and demethylmenaquinone methyltransferase to transfer the electrons to conducting anode via the redox active pheromone lipoproteins localized at the cell membrane

Atomic layers of graphene for microbial corrosion prevention

Graphene is a promising material for many biointerface applications in engineering, medical, and life-science domains. Here, we explore the protection ability of graphene atomic layers to metals exposed to aggressive sulfate-reducing bacteria implicated in corrosion. Although the graphene layers on copper (Cu) surfaces did not prevent the bacterial attachment and biofilm growth, they effectively restricted the biogenic sulfide attack. Interestingly, single-layered graphene (SLG) worsened the biogenic sulfide attack by 5-fold compared to bare Cu. In contrast, multilayered graphene (MLG) on Cu restricted the attack by 10-fold and 1.4-fold compared to SLG-Cu and bare Cu, respectively. We combined experimental and computational studies to discern the anomalous behavior of SLG-Cu compared to MLG-Cu. We also report that MLG on Ni offers superior protection ability compared to SLG. Finally, we demonstrate the effect of defects, including double vacancy defects and grain boundaries on the protection ability of atomic graphene layers