Genetics Commons^™

Reproductive Isolation In The Elegans-Group Of Caenorhabditis, Scott Everet Baird, Sara Rose Seibert

Biological Sciences Faculty Publications

Reproductive isolation is the basis of the Biological Species Definition and can be a driving force of speciation. Theoretical studies have provided models of how reproductive isolation can arise within individual species. Genetic tests of these models are limited to populations in which reproductive isolation is present but not complete. Here, reproductive isolation in the Elgans-Group of the nematode genus Caenorhabditis is reviewed. Pre-mating barriers, assortative fertilization and post-zygotic barriers all have been observed in this clade. In some combinations of species, fertile F1 hybrids can be obtained. Therefore, the Elegans-Group of Caenorhabditis is poised to become an important experimental …

A Path To Success? A Review Of Evolution, Development, And The Predictable Genome By David L. Stern, Hope Hollocher, Charles H. Pence, Grant Ramsey, Michelle M. Wirth

Faculty Publications

No abstract provided.

Staffan Müller-Wille And Hans-Jörg Rheinberger, A Cultural History Of Heredity, Charles H. Pence

Faculty Publications

No abstract provided.

Genetic Diversity In Populations Of Epiphanes Chihuahuaensis (Rotifera: Monogononta) In The Northern Chihuahuan Desert, Diego E. Reyes

Open Access Theses & Dissertations

1. Cryptic speciation in zooplankton is a phenomenon that has been recently gaining much attention. This is due in part to advances in molecular techniques which help in the identification of morphologically indistinct species. Organisms that have been traditionally believed to have cosmopolitan distributions are being found to be composed of cryptic species complexes with high levels of genetic divergence among lineages.

2. Epiphanes chihuahuaensis is a member in the Epiphanes senta species complex. In a previous study by Schröder & Walsh (2007), genetic data, along with morphological and reproductive isolation data were employed to help delineate four species within …

The Causes And Consequences Of Individual Variation In Parental Care Behavior, Daniel P. Wetzel

Theses and Dissertations--Biology

Behavioral traits can be remarkably flexible depending on the conditions in which they are expressed, yet, in spite of this flexibility, persistent differences between individuals appear to limit the potential expression of behaviors. For example, despite evidence that parents provide variable amounts of parental care in response to changing environmental conditions, they also differ in the overall level of care they provide. I used a behavioral reaction norm approach to study individual variation in parental care behavior in free-living house sparrows (Passer domesticus). I investigated the nature of this variation by studying the relationship between different forms of …

Family Matters: An Analysis Of Genetic Relatedness Of Tetraclita Rubescens (The Pink Volcano Barnacle) Over Several Spatial Scales At Monterey And Bodega Bay, California, Kelly N. Chang

Scripps Senior Theses

Inbreeding involves the mating of closely related individuals at a higher frequency than at random; this can decrease the average fitness of populations and individuals by reducing the presence of heterozygotes and augmenting the expression of deleterious genes. Since marine invertebrates exhibit widespread dispersal, their potential for inbreeding is often disregarded. The adult sessile state of barnacles creates the potential for inbreeding as a result of necessary copulation between neighboring individuals. Depending on the degree of mixing that occurs during dispersal, closely related individuals or siblings may settle in close proximity, generating the possibility of kin aggregation and consequent inbreeding. …

A Genetic Survey Of English Sole Populations In The Salish Sea, Elizabeth S. Gutierrez, Gary A. Winans, Jon Baker, Amanda Cope

STAR Program Research Presentations

This summer I interned at the Northwest Fisheries Science Center in Seattle, WA and participated in NOAA’s Salish Sea Project. The Salish Sea Project’s goal is to identify genetically distinctive groups of species in the Salish Sea that may have unique evolutionary and/or adaptive backgrounds. These findings will allow NOAA to promote and monitor the natural production of species in the Salish Sea, to select representative populations for experimental work regarding pollution, ocean acidification and climate change, to contribute to managing the ecosystem for intra- and inter-species diversity, and to help make informed decisions about adaptive management and marine protected …

Widespread Diversity In African Toads (Anura: Amietophrynus), Nancy P. Conkey ^, Eli Greenbaum *

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Comparative Developmental Transcriptomics Of Echinoderms, Roy Vaughn

USF Tampa Graduate Theses and Dissertations

The gastrula stage represents the point in development at which the three primary germ layers diverge. At this point the gene regulatory networks that specify the germ layers are established and the genes that define the differentiated states of the tissues have begun to be activated. These networks have been well characterized in sea urchins, but not in other echinoderms. Embryos of the brittle star Ophiocoma wendtii share a number of developmental features with sea urchin embryos, including the ingression of mesenchyme cells that give rise to an embryonic skeleton. Notable differences are that no micromeres are formed during cleavage …

Systematics Of African Skink In The Panaspis Wahlbergi Complex, Ma. Fernanda Medina^, Eli Greenbaum*

COURI Symposium Abstracts, Summer 2011

No abstract provided.

Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Dicamba-resistant soybeans are being developed to provide an additional herbicide mechanism of action that can be used in soybean, and to provide a tool to help manage or mitigate the evolution of other herbicide-resistant weed populations. The objectives of this thesis were to assess the risk of common Nebraska weeds developing resistance to dicamba, quantify baseline dose-response to dicamba of high-risk weed species, and survey the variability in dicamba dose-response among populations of those species. Twenty-five weed scientists were asked to estimate the risk likelihood of ten weed species evolving resistance to dicamba following the commercialization of dicamba-resistant soybean. Palmer …

Evolutionary Patterns In Deep-Sea Mollusks, Elizabeth Ellen Boyle

Graduate Doctoral Dissertations

The evolution of deep-sea fauna is poorly known. We know little about the scales of population differentiation, radiation and colonization of the deep sea. This dissertation explores evolution in the deep sea at the level of population differentiation on ocean-wide scales in a gastropod species Benthonella tenella and phylogeny of a deep-sea subfamily of protobranch bivalves, Ledellinae. While working on the phylogeny of the Ledellinae the presence of mitochondrial heteroplasmy was discovered.

Genetic variation was quantified within and among populations of deep-sea gastropod Benthonella tenella to identify the extent of population differentiation and potential mechanisms that might isolate gene pools. …

Drafting Human Ancestry: What Does The Neanderthal Genome Tell Us About Hominid Evolution? Commentary On Green Et Al. (2010), Michael Hofreiter

Human Biology

Ten years after the first draft versions of the human genome were
announced, technical progress in both DNA sequencing and ancient DNA
analyses has allowed a research team around Ed Green and Svante Pa¨a¨bo to
complete this task from infinitely more difficult hominid samples: a few
pieces of bone originating from our closest, albeit extinct, relatives, the
Neanderthals. Pulling the Neanderthal sequences out of a sea of contaminating
environmental DNA impregnating the bones and at the same time
avoiding the problems of contamination with modern human DNA is in itself
a remarkable accomplishment. However, the crucial question in the long …

Reconstructing Species Responses To Past Climatic Changes Using Niche Modeling And Genetic Data, Tereza Jezkova

UNLV Theses, Dissertations, Professional Papers, and Capstones

Glacial – interglacial cycles have a pronounced impact on species distributions and genetic structure. Many species shift their distributions to lower latitudes and altitudes during the colder glacial periods and expand northwards and up the elevation during warmer interglacial periods. Some species however are capable of adapting to changing environment which allows them to persist in place despite climatic changes. I explored how climatic changes after the last glacial maximum (LGM) effected two species inhabiting the deserts of western North America: one mammal (Chisel-toothed Kangaroo Rat, Dipodomys microps) and one reptile (Desert Horned Lizard, Phrynosoma platyrhinos). I used …

Genomic Perspectives On Evolution In Bracken Fern, Joshua P. Der

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The fern genus Pteridium comprises a number of closely related species distributed throughout the world. Collectively they are called bracken ferns and have historically been treated as a single species, Pteridium aquilinum. Bracken is notorious as a toxic weed that colonizes open fields and poisons livestock. Bracken is also easily cultured and has become one of the most intensively studied ferns. Bracken has been used as a model system for the study of the fern life cycle, fern gametophyte development, the pheromonal mechanism of sex determination, toxicology, invasion ecology, and climate change. This dissertation places bracken within a global …

Systematics Of The Genus Ptychadena Boulenger, 1917 (Anura: Ptychadenidae) From Democratic Republic Of The Congo, Katrina Marie Weber

Open Access Theses & Dissertations

This thesis increases the scope of previous phylogenetic analyses that revealed high levels of genetic differentiation within the anuran genus Ptychadena. Herein, I increase sampling of Central African populations of Ptychadena by over six times to examine their relationships to other African populations and to search for cryptic species. This study represents the most comprehensive molecular phylogeny of Ptychadena to date. A total of three mitochondrial (12S, 16S, and cyt b) and two nuclear (RAG1 and rhodopsin) genes were sequenced for 67 specimens of Ptychadena. Maximum parsimony, maximum likelihood, and Bayesian analyses were conducted. These analyses revealed …

Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Ancient Dna Identification Of Early 20th Century Simian T-Cell Leukemia Virus Type 1, Sebastien Calvignac, Jean-Michel Terme, Shannon M. Hensley, Pierre Jalinot, Alex D. Greenwood, Catherine Hanni

Biological Sciences Faculty Publications

The molecular identification of proviruses from ancient tissues (and particularly from bones) remains a contentious issue. It can be expected that the copy number of proviruses will be low, which magnifies the risk of contamination with retroviruses from exogenous sources. To assess the feasibility of paleoretrovirological studies, we attempted to identify proviruses from early 20th century bones of museum specimens while following a strict ancient DNA methodology. Simian T-cell leukemia virus type 1 sequences were successfully obtained and authenticated from a Chlorocebus pygerythrus specimen. This represents the first clear evidence that it will be possible to use museum specimens to …

Simpler Mode Of Inheritance Of Transcriptional Variation In Male Drosophila Melanogaster, Marta Wayne, Marina Telonis-Scott, Lisa Bono, Lawrence G. Harshman, Artyom Kopp, Sergey V. Nuzhdin, Lauren Mcintyre

Lawrence G. Harshman Publications

Sexual selection drives faster evolution in males. The X chromosome is potentially an important target for sexual selection, because hemizygosity in males permits accumulation of alleles, causing tradeoffs in fitness between sexes. Hemizygosity of the X could cause fundamentally different modes of inheritance between the sexes, with more additive variation in males and more nonadditive variation in females. Indeed, we find that genetic variation for the transcriptome is primarily additive in males but nonadditive in females. As expected, these differences are more pronounced on the X chromosome than the autosomes, but autosomal loci are also affected, possibly because of X-linked …

Demographic Estimates From Y Chromosome Microsatellite Polymorphisms: Analysis Of A Worldwide Sample, J. Michael Macpherson, Sohini Ramachandran, Lisa Diamond, Marcus W. Feldman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Polymorphisms in microsatellites on the human Y chromosome have been used to estimate important demographic parameters of human history. We compare two coalescent-based statistical methods that give estimates for a number of demographic parameters using the seven Y chromosome polymorphisms in the HGDP-CEPH Cell Line Panel, a collection of samples from 52 worldwide populations. The estimates for the time to the most recent common ancestor vary according to the method used and the assumptions about the prior distributions of model parameters, but are generally consistent with other global Y chromosome studies. We explore the sensitivity of these results to assumptions …

The Use Of Isoelectric Focusing To Assess The Genetic Diversity Of The Cyprinid Fishes: Rhinichthys Cataractae And Rhinichthys Atratulus In West Virginia, Fauzia Alam Miah

Theses, Dissertations and Capstones

In this study, isoelectric focusing is used to separate proteins of Rhinichthys cataractae and R. atratulus and conventional staining is used to identify alleles of six genes. The objective of this work is to determine whether these methods can effectively assay isozymes that may be used to establish the relationship between anthropogenic stress and genetic diversity. Alleles for LDH-A, LDH-B, EST-A, EST-B, EST-C, and EST-D loci were identified for two species of fish, R. atratulus and R. cataractae. Both fish species are known to be sensitive to anthropogenic stress and known to be widely distributed in stressed environments. Alleles …