Isolation of novel microsatellite markers for the clouded Apollo (P. mnemosyne Linnaeus, 1758; Lepidoptera,Papilionidae)

Five novel polymorphic microsatellite loci were isolated and characterized using an enriched genomic DNA library for Parnassius mnemosyne, a European butterfly of conservation concern, and a valuable model for the study of metapopulation dynamics. Allele numbers ranged from 4 to 12 and observed and expected heterozygosities from 0.17 to 0.74 and from 0.26 to 0.835, respectively. Two samples from geographically close populations were analyzed, demonstrating that the new markers can be successfully employed to investigate fine-scale population structure.     

253 Novel polymorphic microsatellites for the saltwater crocodile (Crocodylus porosus)

Genomic elucidation and mapping of novel organisms requires the generation of large genetic resources. In this study, 253 novel and polymorphic microsatellite loci were isolated and characterized for the saltwater crocodile (Crocodylus porosus) by constructing libraries enriched for microsatellite DNA. All markers were evaluated on animals obtained from Darwin Crocodile Farm in the Northern Territory, Australia, and are intended for future use in the construction of a genetic-linkage map for the saltwater crocodile. The 253 loci yielded an average of 4.12 alleles per locus, and those selected for mapping had an average polymorphic information content (PIC) of 0.425.     

Primers targeting mitochondrial genes of avian haemosporidians: PCR detection and differential DNA amplification of parasites belonging to different genera

Haemosporida is a diverse group of vector-borne parasitic protozoa, ubiquitous in terrestrial vertebrates worldwide. The renewed interest in their diversity has been driven by the extensive use of molecular methods targeting mitochondrial genes. Unfortunately, most studies target a 478?bp fragment of the cytochrome b (cytb) gene, which often cannot be used to separate lineages from different genera found in mixed infections that are common in wildlife. In this investigation, an alignment constructed with 114 mitochondrial genome sequences belonging to four genera (Leucocytozoon, Haemoproteus, Plasmodium and Hepatocystis) was used to design two different sets of primers targeting the cytb gene as well as the other two mitochondrial DNA genes: cytochrome c oxidase subunit 1 and cytochrome c oxidase subunit 3. The design of each pair of primers required consideration of different criteria, including a set for detection and another for differential amplification of DNA from parasites belonging to different avian haemosporidians. All pairs of primers were tested in three laboratories to assess their sensitivity and specificity under diverse practices and across isolates from different genera including single and natural mixed infections as well as experimental mixed infections. Overall, these primers exhibited high sensitivity regardless of the differences in laboratory practices, parasite species, and parasitemias. Furthermore, those primers designed to separate parasite genera showed high specificity, as confirmed by sequencing. In the case of cytb, a nested multiplex (single tube PCR) test was designed and successfully tested to differentially detect lineages of Plasmodium and Haemoproteus parasites by yielding amplicons with different sizes detectable in a standard agarose gel. To our knowledge, the designed assay is the first test for detection and differentiation of species belonging to these two genera in a single PCR. The experiments across laboratories provided recommendations that can be of use to those researchers seeking to standardise these or other primers to the specific needs of their field investigations.     

Consensus-degenerate hybrid oligonucleotide primers (CODEHOPs) for the detection of novel viruses in non-human primates

Consensus-degenerate hybrid oligonucleotide primers (CODEHOPs) have proven to be a powerful tool for the identification of novel genes. CODEHOPs are designed from highly-conserved regions of multiply-aligned protein sequences from members of a gene family and are used in PCR amplification to identify distantly-related genes. The CODEHOP approach has been used to identify novel pathogens by targeting amino acid motifs conserved in specific pathogen families. We initiated a program utilizing the CODEHOP approach to develop PCR-based assays targeting a variety of viral families that are pathogens in non-human primates. We have also developed and further improved a computer program and website to facilitate the design of CODEHOP PCR primers. Here, we detail the method for the development of pathogen-specific CODEHOP PCR assays using the papillomavirus family as a target. Papillomaviruses constitute a diverse virus family infecting a wide variety of mammalian species, including humans and non-human primates. We demonstrate that our pan-papillomavirus CODEHOP assay is broadly reactive with all major branches of the virus family and show its utility in identifying a novel non-human primate papillomavirus in cynomolgus macaques.     

Automation of a primer design and evaluation pipeline for subsequent sequencing of the coding regions of all human Refseq genes

Screening for mutations in human disease-causing genes in a molecular diagnostic environment demands simplicity with a view to allowing high throughput approaches. In order to advance these requirements, we have developed and applied a primer design program, termed BatchPD, to achieve the PCR amplification of coding exons of all known human Refseq genes. Primer design, in silico PCR checks and formatted primer information for subsequent web-based interrogation are queried from existing online tools. BatchPD acts as an intermediate to automate queries and results processing and provides exon-specific information that is summarised in a spreadsheet format.     

An approach to delineate primers for a group of poorly conserved sequences incorporating the common motif region

Glutathione synthetase (gshB) has previously been reported to confer tolerance to acidic soil condition in Rhizobium species. Cloning the gene coding for this enzyme necessitates the designing of proper primer sets which in turn depends on the identification of high quality sequence similarity in multiple global alignments. In this experiment, a group of homologous gene sequences related to gshB gene (accession no: gi-86355669:327589-328536) of Rhizobium etli CFN 42, were extracted from NCBI nucleotide sequence databases using BLASTN and were analyzed for designing degenerate primers. However, the T-coffee multiple global alignment results did not show any block of conserved region for the above sequence set to design the primers. Therefore, we attempted to identify the location of common motif region based on multiple local alignments employing the MEME algorithm supported with MAST and Primer3. The results revealed some common motif regions that enabled us to design the primer sets for related gshB gene sequences. The result will be validated in wet lab.     

Isolation and characterization of microsatellite DNA primers for <Emphasis Type="Italic">Sinadoxa corydalifolia</Emphasis> (Adoxaceae)

Sinadoxa corydalifolia is the only species of Sinadoxa (Adoxaceae) with the aberrant morphology. This species has become extremely endangered in the Qinghai-Tibetan Plateau. To provide a population-level genetic profile for investigation and conservation of genetic diversity of this species, we developed 10 new microsatellite loci for this species by the combining biotin capture method. About 31 microsatellites were screened from the library, 10 of the screened microsatellites are polymorphic. The number of alleles per locus in 18 individuals ranged from 3 to 11, expected heterozygosity and observed heterozygosity ranged from 0.3071 to 0.6243 and from 0.1675 to 0.4357, respectively. We further performed cross-priming tests of these primers in another species of the Adoxaceae: Adoxa moschatellina and found 9 of 10 successfully amplified the targeted sequences. These newly developed loci provide a useful tool to investigate the genetic diversity and design the conversation measures of S. corydalifolia and study the genetic divergence and the initial speciation pattern between it and the related species in the Adoxaceae.     

Recombineering Homologous Recombination Constructs in Drosophila

The continued development of techniques for fast, large-scale manipulation of endogenous gene loci will broaden the use of Drosophila melanogaster as a genetic model organism for human-disease related research. Recent years have seen technical advancements like homologous recombination and recombineering. However, generating unequivocal null mutations or tagging endogenous proteins remains a substantial effort for most genes. Here, we describe and demonstrate techniques for using recombineering-based cloning methods to generate vectors that can be used to target and manipulate endogenous loci in vivo. Specifically, we have established a combination of three technologies: (1) BAC transgenesis/recombineering, (2) ends-out homologous recombination and (3) Gateway technology to provide a robust, efficient and flexible method for manipulating endogenous genomic loci. In this protocol, we provide step-by-step details about how to (1) design individual vectors, (2) how to clone large fragments of genomic DNA into the homologous recombination vector using gap repair, and (3) how to replace or tag genes of interest within these vectors using a second round of recombineering. Finally, we will also provide a protocol for how to mobilize these cassettes in vivo to generate a knockout, or a tagged gene via knock-in. These methods can easily be adopted for multiple targets in parallel and provide a means for manipulating the Drosophila genome in a timely and efficient manner.