Genetics and Genomics Commons^™

Ewe Fertility In The Star Accelerated Lambing System, R. M. Lewis, D. R. Notter, D. E. Hogue, B. H. Magee

Department of Animal Science: Faculty Publications

Effects of environmental factors such as ewe age, season of exposure, and time from lambing to exposure on fertility were evaluated using records on 1,084 Dorset ewes in the STAR accelerated lambing system. The STAR program consisted of five 30-d concurrent breeding and lambing periods per year beginning on January 1, March 15, May 27, August 8, and October 20. Fertility in the flock changed in a cyclic and predictable fashion during the year. Changes in prolificacy were less consistent but also tended to show cyclic variation. Matings that occurred within the typical breeding season (August, October, and January) were …

A Gene Correlate Of Geotaxis Near Adh (2-50.1) In Drosophila Melanogaster, Scott F. Stoltenberg, Jerry Hirsch

Department of Psychology: Faculty Publications

As part of a long-term study (38+ years) to identify genetic correlates of geotaxis in Drosophila melanogaster, the investigators report the results of allozyme-level analyses of 2 lines derived from hybridizing high- and low-selected lines that have evolved stable, extreme expressions of geotaxis. Allelic variation at Adh was associated with geotactic performance in 1 hybrid-derived line, but not in another, after 66 free-mating generations beyond the F₂ generation. A second-chromosome gene correlate of geotaxis may lie within 1 map unit of Adh. Population genetic analyses suggest that there were different selection pressures on the hybrid-derived lines and …

Molecular Differentiation Of Alfalfa Weevil Strains (Coleoptera: Curculionidae), S. J. Erney, K. P. Pruess, S. D. Danielson, T. O. Powers

Department of Entomology: Faculty Publications

Mitochondrial DNA was amplified and sequenced from eastern, western, and Egyptian strains of alfalfa weevil, Hypera postica (Gyllenhal). Eastern and Egyptian weevils differed at only 2 nucleotide sites in 1,031 base pairs sequenced; western weevils differed by 5% sequence divergence. Three restriction sites were identified which separated eastern and western haplotypes. No intrastrain polymorphism was detected in 150 weevils from Nebraska. Collections from Lincoln in eastern Nebraska and Scottsbluff in western Nebraska were fixed for the eastern and western haplotypes, respectively. Eastern and western haplotypes were found together in the same fields in a broad overlap region in central Nebraska.

Microevolutionary Patterns And Molecular Markers: The Genetics Of Geographic Variation In Ascaris Suum, Steven A. Nadler

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Molecular markers have been used only rarely to characterize the population genetic structure of nematodes. Published studies have suggested that different taxa may show distinct genetic architectures. Isoenzyme and RAPD markers have been used to investigate geographic variation of Ascaris suum at the level of infrapopulations (nematodes within individual hosts), within localities, and among geographic regions. Independent estimates of genetic differentiation among population samples based on isoenzyme and RAPD data showed similar patterns and substantial correlation. Heterozygote deficiencies within infrapopulations and large values for inbreeding coefficients among infrapopulations suggested that the composition of these populations was not consistent with a …

Analyzing Correlations Of Three Types In Selected Lines Of Drosophila Melanogaster That Have Evolved Stable Extreme Geotactic Performance, Scott F. Stoltenberg, Jerry Hirsch, Stewart H. Berlocher

Department of Psychology: Faculty Publications

The behavior-genetic analysis of Drosophila melanogaster with geotactic performance as the phenotype is an ideal model system with which to investigate the complex relations between heredity and behavior. As part of a long-term, 38-year study, we report 4 experiments that identify and analyze trait correlations in the selected high- and low-geotaxis lines. We performed F₂ correlational analyses and backcrosses to examine 3 types of correlations: (a) genotype-genotype (alcohol dehydrogenase [Adh]-amylase [Amy]), (b) genotype-phenotype (Adh and Amy-geotaxis), and (c) phenotype-phenotype (mate preference–geotaxis). Only the Adh-geotaxis correlation survived meiosis and reappeared in the F …

Media Components Influence Viral Gene Expression Assays In Human Fetal Astrocyte Cultures, Micheline Mccarthy, Charles Wood, Larisa Fedoseyeva, Scott R. Whittemore

Nebraska Center for Virology: Faculty Publications

In vitro neurovirological studies of viral infectivity or viral gene expression may be confounded by the mulHple neural cell types and/or fibrob last contamination present in early passage cultures prepared from dissociated human central nervous system (eNS) tissue. We have developed highly enriched astrocyte cultures for neurovirological study by culturing in a serum-free defined medium, 816, supplemented with basic fibroblast growth factor (FGF-2). Subculture in this medium selects against fibroblast proliferation and favors sustained proliferation of a highly enriched glial fibrillary acidic protein (GFAP)-positive cell population. These astrocytes support productive replication of cytomegalovirus (CMV) and transient expression of transfected CMVand …

A Study Of Euplotes Crassus Telomere Proteins And Related Genes, John Scott Perez

Department of Chemistry: Dissertations, Theses, and Student Research

A novel PCR technique used to amplify Euplotes crassus macronuclear chromosomes was developed to provide scientific proof that an Euplotes crassus 1.0 kb gene is not genetically related to an Oxytricha nova 1.8 kb β-telomere protein gene. Theories and experimental procedures associated with the development of this PCR technique were the product of research that will have a profound impact on future studies of telomere protein genes and telomeric DNA in a multitude of eukaryotic cells. The hypothesis that a β-telomere protein does not exist in Euplotes crassus was supported by the result of this study.

Expression of the recombinant …

Phylogeny Of The Malarial Genus Plasmodium, Derived From Rrna Gene Sequences, Ananias A. Escalante, Francisco J. Ayala

Harold W. Manter Laboratory of Parasitology: Library Materials

Malaria is among mankind's worst scourges, affecting many millions of people, particularly in the tropics. Human malaria is caused by several species of Plasmodium, a parasitic protozoan. We analyze the small subunit rRNA gene sequences of 11 Plasmodium species, including three parasitic to humans, to infer their evolutionary relationships. Plasmodium falciparum, the most virulent of the human species, is closely related to Plasmodium reiehenowi, which is parasitic to chimpanzee. The estimated time of divergence of these two Plasmodium species is consistent with the time of divergence (6-10 million years ago) between the human and chimpanzee lineages. The …

Book Review: The Baculovirus Expression System: A Laboratory Guide (1992) King, L. A. & Possee, R. D., David D. Dunigan

Nebraska Center for Virology: Faculty Publications

The power of molecular biology is unleashed with the ability to clone and sequence genes, and then express these genes in heterologous systems. This sets the stage for the full analysis of proteins that are otherwise difficult to isolate and/or purify, especially when present at very low copy number per cell or when isolated from relatively precious materials. Overexpression of protein is now possible in a number of systems including prokaryotes (e.g., E. coli) and various eukaryotes (yeast, insects, and plants). The issue then becomes, which system (1) most closely reflects the homologous expression with respect to posttranslational modifications, …

Mitochondrial Transfer Rna Genes In A Black Fly, Simulium Vittatum (Diptera: Simuliidae), Indicate Long Divergence From Mosquito (Diptera: Culicidae) And Fruit Fly (Diptera: Drosophilidae), K. P. Pruess, X. Zhu, T. O. Powers

Department of Entomology: Faculty Publications

Sequences are given for nine complete genes and one partial mitochondrial tRNA gene of the black fly, Simulium vittatum (Zetterstedt). Sequenced tRNA genes were for alanine, arginine, asparagine, aspartic acid, glutamic acid, glycine, leucine(CUN), lysine, serine(AGN), and valine. Nucleotides were aligned with the same previously sequenced genes in Aedes albopictus Skuse and Drosophila yakuba Burla. A cluster of six tRNA genes, which differ in arrangement in Ae. albopictus and D. yakuba, was amplified by PCR and found to have the same position and orientation in S. vittatum as in D. yakuba. Overall, similarity with either D. yakuba or …

Altered Expression Of Adenovirus 12 Dna-Binding Protein But Not Dna Polymerase During Abortive Infection Of Hamster Cells, Lynne A. Lucher, Benjawan Khuntirat, Jiansheng Zhao, Peter C. Angeletti

Nebraska Center for Virology: Faculty Publications

Replication of human adenovirus type 12 DNA is blocked in abortively infected baby hamster kidney cells. The activity and accumulation of adenovirus 12 DNA polymerase is equivalent in infected hamster and human cell extracts. However, the accumulation of adenovirus type 12 DNA-binding protein is approximately 120-fold lower in extracts from infected hamster cells when compared to infected permissive human cells. This difference in accumulation is not because of replication of viral DNA during productive infection, since this difference is observed in the presence of hydroxyurea. The DNA-binding protein from infected hamster cells retains the ability to bind denatured DNA-cellulose. An …

Can Genetically Engineered Crops Become Weeds?, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

There are significant differences if the distribution of weedy characteristics among weeds, normal plants, and crops. The world’s most serious weeds possess on the average 10 or 11 of these characters, a random collection of British plants have an average seven of the traits, and crop plants only five. For the average crop to become as “weedy” as the average weed, it would need to acquire five weedy traits. Even using the unlikely assumption that those traits are single loci in which a dominant mutation would provide the weedy character, this would require the simultaneous acquisition of five gene substitutions. …

Adjustment Factors For 120-Day Weaning Weight In Rambouullet Range Lambs, R. M. Lewis, M. Shelton, J. O. Sanders, D. R. Notter, W. R. Pirie, Texas Agricultural Experiment Station

Department of Animal Science: Faculty Publications

Additive and multiplicative environmental adjustments for effects of dam age, lamb sex and birth-rearing type on 120-d weight were derived using data from 819 Rambouillet range lambs. The relationship between mean and variance within environmental effect classes was one criterion for evaluating suitability of adjustment methods. Among lamb sexes and birth-rearing types, larger means were associated with greater variability (P < .01). Variances became homogeneous (P > .10) when data were expressed on a logarithmic scale, suggesting that multiplicative adjustments for these effects are needed. Because variances were homogeneous with respect to dam age (P > .50), additive adjustment factors are suggested for this effect. Validation of a …

Caribbean Island Zoogeography: A New Approach Using Mitochondrial Dna To Study Neotropical Bats, Carleton J. Phillips, Dorothy E. Pumo, Hugh H. Genoways, Phillip E. Ray

University of Nebraska State Museum: Mammalogy Papers

Genetic analysis of animal mitochondrial DNA is a new and valuable addition to the battery of techniques available to zoogeographers. This paper describes characteristics of mitochondrial DNA (mtDNA) that make it applicable for the study of island zoogeography.

Some traditional zoogeographic questions are examined using mtDNA from the Neotropical fruit bat, Artibeus jamaicensis. The specific questions are: 1) To what extent are island populations isolated (that is, does interbreeding occur between the insular subspecies)? 2) Can a single founding female account for the mitochondrial genomes on specific islands in the Antilles? 3) Is there a correlation between the genomic …

Environmental Effects On Remating In Drosophila Melanogaster, Lawrence G. Harshman, Ary A. Hoffman, Timothy Prout

Lawrence G. Harshman Publications

The effects of density and food on remating were investigated using Drosophila melanogaster. The frequency of remating was unaffected by density for some combinations of fly strains but was reduced at low relative densities for other combinations. Until females had used most of their stored sperm, remating was less likely when food was absent or contact with food was prevented. Food availability had little effect on the incidence of remating once stored sperm were depleted and had no effect on initial virgin mating frequency. This study indicates that environmental factors can have a substantial direct influence on the frequency …

Genic Studies Of Lasiurus (Chiroptera: Vespertilionidae), Robert J. Baker, John C. Patton, Hugh H. Genoways, John W. Bickham

University of Nebraska State Museum: Mammalogy Papers

Bats of the genus Lasiurus present a number of interesting systematic problems that are difficult to resolve by traditional techniques. Members of the genus share a suite of derived morphological (Hall and Jones, 1961; Handley , 1960) and karyotypic (Bickham 1979, 1988) characteristics. However, until 1960 (Handley, 1960), members were placed in two genera- Lasiurus and Dasypterus-based primarily upon the presence or absence of the small, first upper premolar. Handley (1960) analyzed the differences and similarities among these two genera and concluded they were not distinct even at a subgeneric level. One goal of this study was to provide …

Relationship Between Herd Management Practices In The Midwest On Milk And Fat Yield, Jeffrey F. Keown

Department of Animal Science: Faculty Publications

A dairy management survey was conducted in fall 1985 and spring 1986 in the nine-state area served by the Midstates Dairy Records Processing Center in Ames, IA. The questionnaire, consisting of 57 questions with 254 possible choices, was used to survey dairy producers on DHI testing in Arkansas, Illinois, Iowa, Kansas, Missouri, Nebraska, North Dakota, Oklahoma, and South Dakota. The questions covered housing pactices, milking equipment and practices, feeding regimens, calf rearing and feeding, feed additives, various management categories, and artificial insemination usage. The survey responses were merged with the 1985 year end rolling herd production averages from the processing …

Mitochondrial Dna Polymorphism In Three Antillean Island Populations Of The Fruit Bat, Artibeus Jamaicensis, Dorothy E. Pumo, Everett Z. Goldin, Beth Elliot, Carleton J. Phillips, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

The Neotropical fruit bat, Artibeus jamaicensis, occurs throughout Latin America and on many islands in the Caribbean. Populations from Jamaica (in the Greater Antilles) to Barbados (in the Lesser Antilles) have been classified as a subspecies (A. j. jamaicensisi separate from that on the Lesser Antillean island of St. Vincent (A. j. schwartzi). Mitochondrial DNA (mtDNA) was isolated from 54 individuals collected on these islands, analyzed by digestion with restriction endonucleases, and the restriction sites were mapped. Three different mtDNA genotypes (16,000 ± 200 bp) were identified: J-1 (16 animals from Jamaica, one from St. Vincent, …

Karyotypic Analysis Of Five Rodents And A Marsupial From Belize, Central America, David W. Burton, John W. Bickham, Hugh H. Genoways, Timothy J. Mccarthy

University of Nebraska State Museum: Mammalogy Papers

Karyotypes and chromosomal banding patterns of six species of small mammals from Belize are presented and discussed in light of relevant data in the literature. Individuals of Heteromys desmarestianus had FN values of 72, which differs from previous reports. G-bands were obtained and compared to fluorescent bands (DAPI) and with the location of NOR sites. The karyotypes of Peromyscus mexicanus, Sigmodon hispidus, Oryzomys couesi, and Ototylomys phyllotis are identical to the karyotypes for these species described in the literature. Active NORs were located on four pairs of chromosomes in O. phyllotis and fluorescent bands obtained with the …

Variation In Population Sex Ratio And Mating Success Of Asexual Lineages Of Alsophila Pometaria (Lepidoptera: Geometridae), Lawrence G. Harshman, Douglas J. Futuyma

Lawrence G. Harshman Publications

Populations of Alsophila pometaria (Harris) are largely gynogenetic and composed of asexual females that must mate with a conspecific male to reproduce. Within this asexual contingent, there are a variety of electrophoretically defined multilocus genotypes. In this study we found that populations differ in sex ratio. We also found that there is an indication of differential mating success among asexual genotypes in a population of A. pometaria.

Male Effects On Fecundity In Drosophila Melanogaster, Ary A. Hoffman, Lawrence G. Harshman

Lawrence G. Harshman Publications

Effects of male Drosophila melanogaster on female fecundity and productivity were examined, considering both females held in containers with males and females exposed to male effects not involving contact. Females were more fecund when male effects were present, and the largest increase was recorded when vials were previously conditioned by males. This effect was probably due to the growth of transmitted microorganisms, which were observed on the laying surface, as further experiments with vials conditioned by virgin females showed a similar increase in fecundity. A male-specific effect was isolated by conditioning bottles containing only agar with males and virgin females. …

The Origin And Distribution Of Clonal Diversity In Alsophila Pometaria (Lepidoptera: Geometridae), Lawrence G. Harshman, Douglas J. Futuyma

Lawrence G. Harshman Publications

A survey of spatial and temporal variation in the frequency of electrophoretically defined genotypes in the geometrid moth Alsophila pometaria revealed a high diversity of uncommon or rare asexual genotypes and clinal distributions of two of the more common clones. There was substantial year-to-year variation in genotype frequencies in seven of eleven sites. Progeny tests have revealed that sexual reproduction is uncommon in two populations and that new asexual genotypes arise from the sexual population. The recurrent origin of asexual genotypes is likely to account for the high genetic and ecological diversity of the asexual contingent of this species’ populations, …

Lavender, A Chick Melanocyte Mutant With Defective Melanosome Translocation: A Possible Role For 10 Nm Filaments And Microfilaments But Not Microtubules, Paula Mayerson, John Brumbaugh

School of Biological Sciences: Faculty Publications

Lavender is a mutation of chick neural-crest-derived melanocytes showing dilute feather pigmentation. This defect, previously attributed to a lack or attenuation of dendrites, was found to be due to a defect in melanosome translocation. The mutant phenotype, of melanin-congested perikarya and pigmentless dendrites is expressed both in vivo and in vitro. Studies with colcemid and cytochalasin B suggest that the avian melanocyte resembles a dispersing amphibian melanophore in its requirement for microfilaments but not microtubules.

Ultrastructural analysis revealed a normal complement of intracellular filaments. Microtubules, however, are scarce. Intermediate (10 nm) filaments surround and are closely associated with intracellular organelles, …

Conservation And Variation Of Nucleotide Sequences In Escherichia Coli Strains Isolated From Nature, Lawrence G. Harshman, Monica Riley

Lawrence G. Harshman Publications

A group of Escherichia coli isolates from nature were compared with one another and with laboratory strains of E. coli with respect to size distribution of chromosomal restriction endonuclease fragments and differences in nucleotide sequences in selected small portions of the genomes. The estimated frequency of base substitutions in nucleotide sequences in and near the trp operons of 26 of the 28 E. coli strains examined ranged from 0.008 to 0.066. Nucleotide sequences in or near λ prophage homologs were significantly more variable than the sequences in or near trp, tnaA, and thyA genes. Thus, the λ-homologous regions …

Heterosis And Breed Effects In Swine, R. K. Johnson

Department of Animal Science: Faculty Publications

An objective of the NC-103 regional swine breeding project is to evaluate inter-population and intra-population performance of domestic and exotic strains of swine. Several cooperating stations have conducted experiments relative to this objective. Projects were not exact replicates, but sufficient overlap allowed combining the information to yield more precise estimates of heterosis and breed effects than was possible from the analyses of data from any single experiment. This publication summarizes data available from NC-103 cooperating stations on breed and heterosis effects in swine. An extensive crossbreeding experiment has been conducted and results published by Canadian researchers Fahmy and Bernard, 1971 …

Apparent Chromosomal Heterosis In A Fossorial Mammal, John C. Patton, Robert J. Baker, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

For the past decade, numerous investigators have attempted to explain the plethora of genetic polymorphism found in nature (see Ayala 1976). However, few researchers have been able to document how polymorphisms have been maintained, whether the polymorphisms were genic or chromosomal. Our investigations into the maintenance of a Robertsonian chromosomal polymorphism in the plains pocket goher, Geomys bursarius major, have revealed evidence that this polymorphism is maintained by differential viabilities of the three chromosomal morphs, with the heterozygote being favored.

Effect Of Graded Levels Of Bambermycins On Turkey Growth Performance, R.J. Grant, P.E. Waibel, T.W. Sullivan, C.L. Quarles

Department of Animal Science: Faculty Publications

Three experiments were conducted in Minnesota, Nebraska, and Colorado to determine the effect on turkey performance of feeding graded levels of bambermycins (Flavomycin ®1) from one day of age to market weight. The body weight and feed efficiency values are averages for 22-week-old males and 18-week-old females. Bambermycins produced significant (P<.001; P<.05) improvements in body weight or feed efficiency in all three experiments. Composite average body weights at 0, 1.1, 2.2, and 4.4 mg bambermycins/kg diet were 10.40, 10.54, 10.59, and 10.64 kg, respectively. Overall, average feed efficiencies from bambermycins at 0, 1.1, 2.2, and 4.4 mg/kg of diet were 2.76, 2.73, 2.72, and 2.71, respectively.

Chromosomal Banding Patterns Of The Holarctic Rodents, Clethrionomys Rutilus And Microtus Oeconomus, C. F. Nadler, V. R. Rausch, E. A. Lyapunova, N. N. Vorontsov, R. S. Hoffman

University of Nebraska State Museum: Mammalogy Papers

Biologists have long been aware of close similarities between the mammalian faunas of northern Eurasia and northern North America (Flerov 1967; Rausch 1953, 1963; Sushkin 1925; Tugarinov 1934). This similarity is particularly strong between species of tundra and taiga ecosystems (Hoffmann and Taber 1967; Hoffmann 1974). Among the species having Holarctic distributions, the boreal red-backed vole, Clethrionomys rutilus (Pallas), and the tundra vole, Microtus oeconomus (Pallas) (Rausch, op. cit.), of the subfamily Arvicolinae (= Microtinae) (Kretzoi 1962; Repenning 1968), have wide distributions in Eurasia where they inhabit, but are not restricted to, tundra (Ognev 1950; Corbet 1966). East of the …

Subjective Evaluation Of Teat Canal Anatomy, R. D. Appleman

Department of Animal Science: Faculty Publications

Since radiographic techniques have shown that streak canals with larger diameters tend to milk-out faster and are more susceptible to new intramammary infections, a practical visual test was sought to provide easier determination of cows with either extremely narrow (slow milking) or extra wide (susceptible to new infections) streak canals.

A subjective teat classification scheme was developed to describe five different teat-end shapes in 159 Holstein and Brown Swiss cows in the University of Nebraska dairy herd. Approximately one-fourth of the cattle had pointed or round teat ends, one-half had fiat or near flat, and one-fourth were either disk or …

Genetic Aspects Of Calving Ease, James S. Brinks

Department of Animal Science: Faculty Publications

Several trends in cattle production and marketing are becoming evident. Leaner and perhaps heavier muscled slaughter cattle will be in demand through the chain from consumers back through retailers, packers, feeders and finally the producers. Emphasis on growth in the feedlot will continue. Thus, the feedlot and carcass characteristics desired point towards fairly large, heavier muscled cattle. At the producer level, increased emphasis is being placed on matching cow size, milk level, and overall biological type to available resources. Thus, the trend for maternal herds in the Great Plains point towards an adapted, probably moderate size, and milking cow that …