Life Sciences Commons^™

An Integrated Genetic Linkage Map For Silkworms With Three Parental Combinations And Its Application To The Mapping Of Single Genes And Qtl, Shuai Zhan, Jianhua Huang, Qiuhong Guo, Yunpo Zhao, Weihua Li, Xuexia Miao, Marian R. Goldsmith, Muwang Li, Yongping Huang

Marian R Goldsmith

Background: Bombyx mori, the domesticated silkworm, is a well-studied model insect with great economic and scientific significance. Although more than 400 mutations have been described in silkworms, most have not been identified, especially those affecting economically-important traits. Simple sequence repeats (SSRs) are effective and economical tools for mapping traits and genetic improvement. The current SSR linkage map is of low density and contains few polymorphisms. The purpose of this work was to develop a dense and informative linkage map that would assist in the preliminary mapping and dissection of quantitative trait loci (QTL) in a variety of silkworm strains. Results: …

Evolution Of Repetitive Proteins: Spider Silks From Nephila Clavipes (Tetragnathidae) And Araneus Bicentenarius (Araneidae), Richard D. Beckwitt, Steven Arcidiacono, Robert Stote

Richard D Beckwitt

Spider silks are highly repetitive proteins, characterized by regions of polyalanine and glycine-rich repeating units. We have obtained two variants of the Spidroin 1 (NCF-1) silk gene sequence from Nephila clavipes. One sequence (1726 bp) was from a cloned cDNA, and the other (1951 bp) was from PCR of genomic DNA. When these sequences are compared with each other and the previously published Spidroin 1 sequence, there are differences due to sequence rearrangements, as well as single base substitutions. These variations are similar to those that have been reported from other highly repetitive genes, and probably represent the results …

أمراض الأطفال المزمنة, Suad Fahad Alferaih

Dr. Suad Fahad AlFuraih

No abstract provided.

Deglaciation Explains Bat Extinction In The Caribbean, Liliana M. Davalos, Amy L. Russell

Amy L. Russell

Pre-Settlement History May Obscure The Effect Of Forest Fragmentation On Genetic Variation In Eastern Red-Backed Salamanders, Mark Jordan, Douglas Morris, Scott Gibson

Mark A. Jordan

No abstract provided.

Two Different High Throughput Sequencing Approaches Identify Thousands Of De Novo Genomic Markers For The Genetically Depleted Bornean Elephant., Reeta Sharma, Benoit Goossens, Benoit Goossens, Célia Kun-Rodrigues, Tatiana Teixeira, Nurzhafarina Othman, Nurzhafarina Othman, Jason Q. Boone, Nathaniel K. Jue, Craig Obergfell, Rachel J. O'Neill, Lounès Chikhi, Lounès Chikhi, Lounès Chikhi

Nathaniel Jue

Regulatory Elements Of Xenopus Col2a1 Drive Cartilaginous Gene Expression In Transgenic Frogs, Ryan R. Kerney, Brian K. Hall, James Hanken

Ryan Kerney

This study characterizes regulatory elements of collagen 2α1 (col2a1) in Xenopus that enable transgene expression in cartilage-forming chondrocytes. The reporters described in this study drive strong cartilage-specific gene expression, which will be a valuable tool for further investigations of Xenopus skeletal development. While endogenous col2a1 mRNA is expressed in many embryonic tissues, its expression becomes restricted to tadpole and adult chondrocytes. This chondrocyte-specific expression is recapitulated by col2a1 reporter constructs, which were tested through I-SceI meganuclease-mediated transgenesis. These constructs contain a portion of the Xenopus tropicalis col2a1 intron, which aligns to a cartilage-specific intronic enhancer that has been well characterized …

Cryptococcal Genotype Influences Immunologic Response And Human Clinical Outcome After Meningitis, Darin L. Wiesner, Oleksandr Moskalenko, Jennifer M. Corcoran, Tami Mcdonald, Melissa A. Rolfes, David B. Meya, Henry Kajumbula, Andrew Kambugu, Paul R. Bohjanen, Joseph F. Knight, David R. Boulware, Kirsten Nielsen

Tami McDonald

No abstract provided.

The Role Of Epigenetics In Evolution: The Extended Synthesis, Aaron W. Schrey, Christina L. Richards, Victoria Meller, Vincent Sollars, Douglas M. Ruden

Vincent E Sollars

Evolutionary biology is currently experiencing an emergence of several research topics that transcend the boundaries of the Modern Synthesis, which was the last major conceptual integration in evolutionary biology [1]. The Modern Synthesis used the concepts of population genetics to integrate Mendelian genetics with evolution by natural selection [2]. Pigliucci [3, and citations within] identified several major areas of innovation that transcend the Modern Synthesis: epigenetics, evolvability, phenotypic plasticity, evolution on adaptive landscapes, evolutionary developmental biology, and systems biology. Integrating these new ideas with the Modern Synthesis will form a new conceptual framework of evolution, which they termed the Extended …

Disparities In Allele Frequencies And Population Differentiation For 101 Disease-Associated Single Nucleotide Polymorphisms Between Puerto Ricans And Non-Hispanic Whites, Josiemer Mattei, Laurence D. Parnell, Chao-Qiang Lai, Bibiana Garcia-Bailo, Xian Adiconis, Jian Shen, Donna Arnett, Serkalem Demissie, Katherine L. Tucker, Jose M. Ordovas

Katherine L. Tucker

Background: Variations in gene allele frequencies can contribute to differences in the prevalence of some common complex diseases among populations. Natural selection modulates the balance in allele frequencies across populations. Population differentiation (FST) can evidence environmental selection pressures. Such genetic information is limited in Puerto Ricans, the second largest Hispanic ethnic group in the US, and a group with high prevalence of chronic disease. We determined allele frequencies and population differentiation for 101 single nucleotide polymorphisms (SNPs) in 30 genes involved in major metabolic and disease-relevant pathways in Puerto Ricans (n = 969, ages 45–75 years) and compared them to …

Regression Approaches For Microarray Data Analysis, Mark R. Segal, Kam D. Dahlquist, Bruce R. Conklin

Mark R Segal

A variety of new procedures have been devised to handle the two sample comparison (e.g., tumor versus normal tissue) of gene expression values as measured with microarrays. Such new methods are required in part because of some defining characteristics of microarray-based studies: (i) the very large number of genes contributing expression measures which far exceeds the number of samples (observations) available, and (ii) the fact that by virtue of pathway/network relationships, the gene expression measures tend to be highly correlated. These concerns are exacerbated in the regression setting, where the objective is to relate gene expression, simultaneously for multiple genes, …

Phylogenetics Of Morus (Moraceae) Inferred From Its And Trnl-Trnf Sequence Data., Madhav Nepal

Madhav Nepal

Comparative Sequence Analysis Of Fatty Acid Desaturase 2 (Fad2) Cdna Sequences From The Compositae [Asteraceae], Paul Ames Muller Jr.

Paul Muller

Fatty acid desaturases are enzymes capable of modifying carbon-carbon bonds within fatty acids. All higher plants contain one or more oleic acid desaturases that catalyze insertion of a double bond between carbons 12 and 13 of oleic acid to produce linoleic acid, an unsaturated fatty acid. However, this family of enzymes may vary in specificity and are responsible for a wide spectrum of unsaturated fatty acids found in nature that play important ecological, physiological, and industrial roles. Here, I examine nucleotide sequence evolution and predict structural changes of translated expressed Fatty Acid Desaturase 2 (FAD2) cDNA sequences in the Compositae …

Mama What Is Celiac, Suad Fahad Alferaih

Dr. Suad Fahad AlFuraih

قصة ماما ماهو السلياك

Estrogenic Compounds Downstream From Three Small Cities In Eastern Nebraska: Occurrence And Biological Effect, Marlo K. Sellin, Daniel D. Snow, Debbie L. Akerly, Alan S. Kolok

Daniel D Snow

Recent studies have detected estrogenic compounds in surface waters in North America and Europe. Furthermore, the presence of estrogenic compounds in surface waters has been attributed, in some cases, to the discharge of wastewater treatment plant (WWTP) effluent. The primary objective of the current study was to determine if WWTP effluent contributes estrogens to the surface waters of Nebraska. A second objective of this study was to determine if estrogens were found in concentrations sufficient enough to manifest feminizing effects on fish. These objectives were satisfied by deploying polar organic chemical integrative samplers (POCIS) and caged fathead minnows at eight …

Comparison Of Two Gelling Agents For Screwworm (Diptera: Calliphoridae) Larval Diets, David B. Taylor

David B. Taylor

A sodium polyacrylamide polyacrylate gelling agent, Water-Lock G-400, and a galactan polysaccharide agent, carrageenan, were compared for solidifying larval diets of the screwworm, Cochliomyia hominivorax (Coquerel). Water-Lock diet produced larger pupae with less larval mortality than did carrageenan diet. Pupae from larvae reared on the Water-Lock diet exhibited higher emergence and produced adults with higher fecundity. Water-Lock diet also produced larger larvae at 56 h after oviposition. Densities in excess of 300 mg of eggs (16,200 eggs) per liter of Water-Lock gelled diet did not increase larval yield but did reduce larval weight and survival.

Mitochondrial Dna Variation Among Muscidifurax Spp. (Hymenoptera: Pteromalidae), Pupal Parasitoids Of Filth Flies (Diptera), David B. Taylor, Richard D. Peterson Ii, Allen L. Szalanski, James J. Petersen

David B. Taylor

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing analyses were used to characterize an amplicon of ~625 bp in 4 of the 5 nominate species of Muscidifurax Girault & Sanders, pupal parasitoids of muscoid flies. A single polymorphic nucleotide site was observed among 2 samples of M. raptor Girault & Sanders. No sequence variation was observed among 3 samples of M. raptorellus Kogan & Legner. The sequence of M. uniraptor Kogan & Legner was identical to that of M. raptorellus. Nucleotide divergence among the Muscidifurax spp. ranged from 0.14 to 0.18 substitutions per nucleotide. Muscidifurax zaraptor Kogan & Legner …

Identification Of Screwworm Species By Polymerase Chain Reaction-Restriction Fragment Length Polymorphism, David B. Taylor, Allen L. Szalanski, Richard D. Peterson Ii

David B. Taylor

Restriction fragment length polymorphisms in polymerase chain reaction amplified fragments (PCR-RFLP) of mitochondrial DNA were used to differentiate species of New World screwworms (Diptera : Calliphoridae) . Twenty-seven restriction enzymes were screened on five regions of mtDNA . Eleven restriction fragment length patterns differentiated New World screwworm, Cochliomyia hominivorax (Coquerel), from secondary screwworm, Cochliomyia macellaria (F.) . Five restriction fragment length patterns were polymorphic in C. hominivorax while all fragment patterns were fixed in C. macellaria. Diagnostic restriction fragment length patterns were used for species diagnosis, whereas intraspecific variable patterns were used to characterize field samples and laboratory strains . …

Population Genetics And Gene Variation In Primary And Secondary Screwworm (Diptera : Calliphoridae), David B. Taylor, Richard D. Peterson Ii

David B. Taylor

Allozyme variation in screwworm, Cochliomyia hominivorax (Coquerel), and secondary screwworm, C. macellaria (F.), populations from northwest Costa Rica was examined . Variability was observed in 11 of 13 enzyme loci and the frequency of the most common allele was <0.95 for 5 loci in screwworm . In secondary screwworm, 12 of 13 loci were variable and the frequency of the most common allele was <0.95 for 6 loci . Expected heterozygosities were 0.149 and 0.160 for screwworm and secondary screwworm, respectively. Goodness-of-fit statistics for Hardy-Weinberg equilibrium and Wrights F statistics indicated that both species are panmictic with no evidence of …

Genetic And Morphological Comparisons Of New And Old World Populations Of Spalangia Species (Hymenoptera: Pteromalidae), David B. Taylor, Roger Moon, Gary Gibson, Allen L. Szalanski

David B. Taylor

The genetic similarity of New and Old World samples of Spalangia spp. (Hymenoptera: Pteromalidae) was examined using two ribosomalDNAregions. The species examined were Spalangia cameroni Perkins, Spalangia endius Walker, Spalangia gemina Bouček, Spalangia nigra Latreille, Spalangia nigroaenea Curtis, and Spalangia slovaca Bouček. Two species of Muscidifurax, Muscidifurax raptor Girault & Sanders and Muscidifurax zaraptor Kogan & Legner (Hymenoptera: Pteromalidae) were included as outgroup taxa. The internal transcribed spacer (ITS)-1 region was highly variable among Spalangia species with many insertions/deletions making alignment of the sequences difÞcult. The D2-D3 region of the 28s ribosomal gene and the nuclear rDNA 18s gene were …

Assessing Nuclear And Mitochondrial Dna Sequence Variation Within Steinernema (Rhabditida: Steinernematidae), Allen L. Szalanski, David B. Taylor, Peter G. Mullin

David B. Taylor

DNA sequence analysis was used to characterize the nuclear ribosomal DNA ITS1 region and a portion of the COII and 16S rDNA genes of the mitochondrial genome from Steinernema entomopathogenic nematodes. Nuclear ITS1 nucleotide divergence among seven Steinernema spp. ranged from 6 to 22%, and mtDNA divergence among five species ranged from 12 to 20%. No intraspecific variation was observed among three S. feltiae strains. Phylogenetic analysis of both nuclear and mitochondrial DNA sequences confirms the existing morphological relationships of several Steinernema species. Both the rDNA ITS1 and mtDNA sequences were useful for resolving relationships among Steinernema taxa.

Identification Of Muscidifurax Spp. By Polymerase Chain Reaction-Restriction Fragment Length Polymorphism, David Taylor, Allen Szalanski

David B. Taylor

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the nuclear ribosomal ITS1 region was used to differentiate Muscidifurax (Hymenoptera: Pteromalidae) species which are parasitoids of filth fly pupae. Three restriction enzymes, Dpn 11, Mse I, and Taq I, produced restriction patterns which were diagnostic for the four species analyzed, M. raptor, M. raptorellus, M. uniraptor, and M. zaraptor. Seven other restriction enzymes were able to differentiate one or more of the species and can be used alone, or in combination with other enzymes, to verify identifications. No intraspecific variation was observed among the populations examined. The utility of the …

Mitochondrial Dna Variation In Screwworm, David B. Taylor, Allen L. Szalanski, Richard D. Peterson Ii

David B. Taylor

Polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) analysis was used to characterize mitochondrial DNA (mtDNA) variation in screwworms, Cochliomyia hominivorax, and secondary screwworm, C. macellaria, from the Caribbean, North America and South America. Four amplicons, totaling 7.1 kb, were analysed with sixteen restriction enzymes. A total of 133 restriction sites was observed in the two species, 104 in C. hominivorax, of which nineteen were variable, and ninety-five in C. macellaria, none of which was variable. Fourteen mtDNA haplotypes were observed among eighteen C. hominivorax examined. Mean divergence between C. hominivorax haplotypes (d) was 0.0064 …

Population Genetics And Gene Variation Of Stable Fly Populations (Diptera: Muscidae) In Nebraska, Allen L. Szalanski, David B. Taylor, Richard D. Peterson Ii

David B. Taylor

Genetic variation in stable fly, Stomoxys calcitrans (L.),populations from Nebraska, Canada, and Texas was sampled. Four of 12 allozyme loci were polymorphic, with an average of 1.7 alleles per locus. Observed and expected heterozygosities were 0.086 and 0.070,respectively. Nei's genetic distance between populations averaged 0.001 and ranged from 0.000 to 0.005. Wright's F statistics revealed greater variation within than among populations. Allele frequencies were homogeneous among temporal samples from a single population. Polymerasechain reaction—restriction fragment length polymorphism (PCR—RFLP) analysis of 6.4 kb of the mitochondrial DNA genome with 16 restriction enzymes revealed no variation in stable fly populations from Canada, …

Genetics Of The Screwworm Fly, David B. Taylor, Estela Martinez Cuevas

David B. Taylor

Three spontaneous eye mutants of Cochliomyia hominivorax, the screwworm fly, are described and characterized. The mutants, yellow eye (ye), orange eye (or), and white eye (wh), segregate independently and are recessive. Yellow eye is recessively epistatlc to orange eye and dominantly epistatic to white eye. All three mutants have complete penetrance, are autosomal, and have little effect on fly viabillty under laboratory conditions.

Comparison Of Gelled And Meat Diets For Rearing Screwworm, Cochliomyia Hominivorax (Diptera: Calliphoridae), Larvae, David B. Taylor, Robert L. Mangan

David B. Taylor

A liquid diet solidified with an acrylamide-acrylate polymer gelling agent (Water-Lock) was compared with a standard meat diet for rearing screwworm, Cochliomyia hominivorax (Coquerel), larvae. Size and yield of larvae reared on gel diet were equal to, or greater than, those of larvae reared on meat diet. Duration of larval development was increased by ca. 13 h on gel diet; however, variability of pupal weight and larval survival over generations were reduced when gel diet was used. Larval size was also more uniform over the 3-d period when larvae leave the rearing medium to pupate (crawl-off). Gelled diet was more …

Genetic Similarity Among Pheromone And Voltinism Races Of Ostrinia Nubilalis (Hubner) (Lepidoptera: Crambidae), P. C. R. G. Marcon, David B. Taylor, C. E. Mason, R. L. Hellmich, Blair Siegfried

David B. Taylor

The genetic variability of seven European corn borer populations, Ostrinia nubilalis, from North America and Europe was assessed by polymerase chain reaction- restriction fragment length polymorphism (PCRRFLP) analysis and DNA sequencing. The nuclear ribosomal internal transcribed spacer 1 (ITS-1) region (≈ 500 base pair [bp]) and four mitochondrial (mtDNA) regions (1550 bp total) were examined. The smartweed borer, Ostrinia obumbratalis, and south-Western corn borer, Diatraea grandiosella, were used for comparisons. Of 106 restriction sites identified (80 in mtDNA and 26 in ITS-1), none differentiated geographical populations, pheromone races, or voltine ecotypes of the European corn borer. The lack of variation …

Susceptibility Of House Fly (Diptera: Muscidae) Larvae To Entomopathogenic Nematodes (Rhabditida: Heterorhabditidae, Steinernematidae, David B. Taylor, Allen L. Szalanski, Byron J. Adams, Richard D. Peterson Ii

David B. Taylor

The potential for entomopathogenic nematodes to control flies in cattle feedlots was determined by screening 40 strains representing 8 species of Heterorhabditis Poinar and 5 species of Steinernema Travassos for virulence toward 3rd-instar house flies (maggots), Musca domestica L. None of the 22 strains of Heterorhabditis infecting maggots caused significant levels of mortality in a filter paper assay. Ten strains of Steinernema infected maggots, of which 7 strains--4 S. carpocapsa (Weiser), 2 S. feltiae (Filipjev), and 1 S. scapterisci (Nguyen & Smart) caused significant mortality. Ten Heterorhabditis strains and 10 Steinernema strains successllly reproduced for 22 generations in maggots. No …

Population Genetics And Gene Variation In Secondary Screwworm (Diptera: Calliphoridae), David Taylor, Richard Peterson Ii

David B. Taylor

Allozyme variation in 4 populations of secondary screwworm, Cochliomyia macellaria (F.), representing North, Central, and South America was examined . Variability was observed in 12 of 13 enzyme loci, and the frequency of the most common allele was <0.95 for 6 loci . Observed and expected heterozygosities were 0.149 and 0.154, respectively. Nei's genetic distances were ≤ 0.001. Goodness-of-fit statistics for Hardy-Weinberg equilibrium and Wright's FIS statistics indicated random mating within populations . Wright's FST statistics and chi-square contingency analyses indicated homogeneous gene frequencies among the populations. These data suggest that C. macellaria is a panmictic species with high levels …

Gelled Diet For Screwworm (Diptera: Calliphoridae) Mass Production, David B. Taylor, Jimmy C. Bruce, Rene Garcia

David B. Taylor

A rearing system based on a diet gelled with Water-Lock G400, a synthetic superabsorbent (poly(2-propenamide-co-2-propenoic acid, sodium salt))( WL), was compared with the standard rearing system (liquid diet suspended in acetate fibers) for the mass production of screwworms, Cochlomyia hominivorax (Coquerel). The WL rearing system yielded 2% heavier pupae, 32% higher egg to pupa survival, and required 54% less diet and 88% less labor than the standard rearing system. Other advantages of the WL system include reduced susceptibility to suboptimal environmental conditions and labor practices, and characteristics conducive to centralization and mechanization of rearing procedures.