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Articles 1 - 9 of 9
Full-Text Articles in Life Sciences
Analyzing Phototaxis And Related Visual Behaviors Among Diverse Species Of Drosophila, Madeline M. Hill
Analyzing Phototaxis And Related Visual Behaviors Among Diverse Species Of Drosophila, Madeline M. Hill
Honors Theses
Phototaxis and related visual behaviors can vary between species, and thus members of the genus Drosophila make an excellent study system to examine the evolution of vision. While some existing research points to these phototactic behaviors arising due to mating requirements or due to their species-specific ecology or environmental factors, there exists a lack of understanding as to why striking behavioral differences can exist between closely related species, or between members belonging to the same genus. The present research seeks to uncover the specifics regarding these discrepancies in visual evolution and aims to provide a foundation of knowledge about visual …
A Tale Of Two Genomes: The Complex Interplay Between The Mitochondrial And The Nuclear Genomes, Abhilesh S. Dhawanjewar
A Tale Of Two Genomes: The Complex Interplay Between The Mitochondrial And The Nuclear Genomes, Abhilesh S. Dhawanjewar
School of Biological Sciences: Dissertations, Theses, and Student Research
Mitochondria, the product of an ancient endosymbiotic event are pivotal to eukaryotic cells by synthesizing the majority of the cell’s ATP output. However, modern- day mitochondria are completely dependent on more than one thousand nuclear-encoded products for their function and the maintenance of their genomes. The fundamentally different ways in which the mitochondrial (mtDNA) and the nuclear (nucDNA) genomes are replicated and inherited lead to captivating coevolutionary dynamics between them. The aims of this dissertation are to investigate the coevolutionary dynamics between the mitochondrial and nuclear genomes at three distinct biological scales. At the organismal level, we use a Drosophila …
Testing The Drosophila Maternal Haploid Gene For Functional Divergence And A Role In Hybrid Incompatibility, Dean M. Castillo, Benjamin Mccormick, Connor M. Kean, Sahana Natesan, Daniel A. Barbash
Testing The Drosophila Maternal Haploid Gene For Functional Divergence And A Role In Hybrid Incompatibility, Dean M. Castillo, Benjamin Mccormick, Connor M. Kean, Sahana Natesan, Daniel A. Barbash
Nebraska Extension: Faculty and Staff Publications
Crosses between Drosophila simulans females and Drosophila melanogaster males produce viable F1 sons and poorly viable F1 daughters. Unlike most hybrid incompatibilities, this hybrid incompatibility violates Haldane’s rule, the observation that incompatibilities preferentially affect the heterogametic sex. Furthermore, it has a different genetic basis than hybrid lethality in the reciprocal cross, with the causal allele in Drosophila melanogaster being a large species-specific block of complex satellite DNA on its X chromosome known as the 359-bp satellite, rather than a protein-coding locus. The causal allele(s) in Drosophila simulans are unknown but likely involve maternally expressed genes or factors since the F1 …
Genome-Wide Gene Expression Effects Of Sex Chromosome Imprinting In Drosophila, Bernardo Lemos, Alan T. Branco, Pan-Pan Jiang, Daniel L. Hartl, Colin D. Meiklejohn
Genome-Wide Gene Expression Effects Of Sex Chromosome Imprinting In Drosophila, Bernardo Lemos, Alan T. Branco, Pan-Pan Jiang, Daniel L. Hartl, Colin D. Meiklejohn
School of Biological Sciences: Faculty Publications
Imprinting is well-documented in both plant and animal species. In Drosophila, the Y chromosome is differently modified when transmitted through the male and female germlines. Here, we report genome-wide gene expression effects resulting from reversed parent-of-origin of the X and Y chromosomes. We found that hundreds of genes are differentially expressed between adult male Drosophila melanogaster that differ in the maternal and paternal origin of the sex chromosomes. Many of the differentially regulated genes are expressed specifically in testis and midgut cells, suggesting that sex chromosome imprinting might globally impact gene expression in these tissues. In contrast, we observed much …
Little Evidence For Demasculinization Of The Drosophila X Chromosome Among Genes Expressed In The Male Germline, Colin D. Meiklejohn, Daven C. Presgraves
Little Evidence For Demasculinization Of The Drosophila X Chromosome Among Genes Expressed In The Male Germline, Colin D. Meiklejohn, Daven C. Presgraves
School of Biological Sciences: Faculty Publications
Male-biased genes—those expressed at higher levels in males than in females—are underrepresented on the X chromosome of Drosophila melanogaster. Several evolutionary models have been posited to explain this so-called demasculinization of the X. Here, we show that the apparent paucity of male-biased genes on the X chromosome is attributable to global X-autosome differences in expression in Drosophila testes, owing to a lack of sex chromosome dosage compensation in the male germline, but not to any difference in the density of testis-specific or testis-biased genes on the X chromosome. First,using genome-wide gene expression data from 20 tissues,we find no evidence …
Evolution Of Starvation Resistance In Drosophila Melanogaster: Measurement Of Direct And Correlated Responses To Artificial Selection, Tiffany E. Schwasinger-Schmidt, Stephen D. Kachman, Lawrence G. Harshman
Evolution Of Starvation Resistance In Drosophila Melanogaster: Measurement Of Direct And Correlated Responses To Artificial Selection, Tiffany E. Schwasinger-Schmidt, Stephen D. Kachman, Lawrence G. Harshman
Lawrence G. Harshman Publications
Laboratory selection for resistance to starvation has been conducted under relatively controlled conditions to investigate direct and correlated responses to artificial selection. With regard to starvation resistance, there are three physiological routes by which the trait can evolve: resource accumulation, energy conservation and starvation tolerance. A majority of energetic compounds and macromolecules including triglycerides, trehalose and other sugars, and soluble protein increased in abundance as a result of selection. Movement was additionally investigated with selected males moving less than control males and selected females exhibiting a similar response to selection. Results obtained from this study supported two of the possible …
The Developmental And Molecular Basis Of Allometry In Drosophila, Alexander W. Shingleton, Jennifer A. Brisson, David L. Stern
The Developmental And Molecular Basis Of Allometry In Drosophila, Alexander W. Shingleton, Jennifer A. Brisson, David L. Stern
School of Biological Sciences: Faculty Publications
Allometry is the scaling relationship between the size of an organism and the size of its constituent parts. Despite its obvious developmental and evolutionary importance, very little is known of the mechanisms that regulate allometries. Here, we look at one particular type of allometry—that created by rearing Drosophila under different nutritional conditions. Drosophila larvae that are fed increasingly suboptimal diets eclose into increasingly small adults with increasingly small body parts. Surprisingly, however, the male genitals remain approximately the same size under a range of nutritional conditions. The genitals therefore maintain a different allometric relationship with the body than other structures. …
The Physiology Of Life History Trade-Offs In Animals, Anthony J. Zera, Lawrence G. Harshman
The Physiology Of Life History Trade-Offs In Animals, Anthony J. Zera, Lawrence G. Harshman
Anthony Zera Publications
The functional causes of life history trade-offs have been a topic of interest to evolutionary biologists for over six decades. Our review of life history trade-offs discusses conceptual issues associated with physiological aspects of trade-offs, and it describes recent advances on this topic. We focus on studies of four model systems: wing polymorphic insects, Drosophila, lizards, and birds. The most significant recent advances have been: (a) incorporation of genetics in physiological studies of trade-offs, (b) integration of investigations of nutrient input with nutrient allocation, (c) development of more sophisticated models of resource acquisition and allocation, (d) a shift to more …
The Functional Organization Of The Vestigial Locus In Drosophila Melanogaster, Jim A. Williams, Audrey L. Atkin, John B. Bell
The Functional Organization Of The Vestigial Locus In Drosophila Melanogaster, Jim A. Williams, Audrey L. Atkin, John B. Bell
School of Biological Sciences: Faculty Publications
Vestigial mutants are associated with imaginal disc cell death which results in the deletion of adult wing and haltere structures. The vestigial locus has previously been cloned, and mutational lesions associated with a number of vg alleles were mapped within a 19 kb DNA region defined as essential for vg function. Herein we report the identification and characterization of a developmentally regu-lated 3.8 kb vg transcript which is spliced from exons distributed throughout the essential interval defined above. All the characterized classical alleles have predictable effects on this transcription unit, and the severity of this effect is directly proportional to …