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Full-Text Articles in Life Sciences
Assessing The Role Of Hybridization In The Evolution Of Two Common Lineages Of Lichen-Forming Fungi, Rachel Keuler
Assessing The Role Of Hybridization In The Evolution Of Two Common Lineages Of Lichen-Forming Fungi, Rachel Keuler
Theses and Dissertations
Once thought to be an evolutionary dead-end, hybridization is now being detected in genomes across kingdoms, perhaps even playing an integral role in evolution. In chapter 1, I investigated the potential influences of hybridization on the evolution of a group of vagrant, asexual species in the Rhizoplaca melanophthalma species group. I sequenced the mitochondrial and nuclear genomes of 55 specimens and found well-supported nuclear phylogenies of both datasets. There were, however, multiple instances of discordance between the mitochondrial and nuclear trees, which can be caused by hybridization. PhyloNet and ABBA-BABA also detected widespread hybridization among this group. In chapter 2, …
Resolving Relationships And Revealing Hybridization In Aliciella Subsection Subnuda (Polemoniaceae), Theresa Conley Saunders
Resolving Relationships And Revealing Hybridization In Aliciella Subsection Subnuda (Polemoniaceae), Theresa Conley Saunders
Theses and Dissertations
Phylogenetics is crucial in the study of evolutionary processes and the determination of appropriate conservation units, and often these efforts are complicated by hybridization and introgression. Aliciella subsection Subnuda consists of seven species of herbaceous plants occurring in Utah and the Four Corners region of North America. Previous molecular and morphological work left relationships in the subsection unresolved. Here, we use comparative DNA sequencing of ITS and cpDNA regions and RAD-seq data to clarify phylogenetic relationships and examine the role of hybridization in the subsection. We construct haplotype and nucleotype networks from the cpDNA and ITS sequence matrices and compare …
Population Structure, Genetic Diversity, Geographic Distribution, And Morphology Of Two Boechera (Brassicaceae) Parental Species (Boechera Thompsonii And Boechera Formosa) And Of Their Resultant Hybrid Boechera Duchesnensis, Christina Elizabeth Fox Call
Population Structure, Genetic Diversity, Geographic Distribution, And Morphology Of Two Boechera (Brassicaceae) Parental Species (Boechera Thompsonii And Boechera Formosa) And Of Their Resultant Hybrid Boechera Duchesnensis, Christina Elizabeth Fox Call
Theses and Dissertations
Background: Over the relatively short period of its evolutionary history, Boechera (Brassicaceae) has undergone rapid radiation that has produced 70+ morphologically distinct, sexual diploids. However, reproductive isolation has moved more slowly than morphological divergence in this group and the diploids appear to hybridize frequently where they coexist. Boechera duchesnensis appears to be the result of hybridization between its putative parents Boechera thompsonii and Boechera formosa. Objectives: The objectives of this study are to (i) analyze and document genetic diversity patterns in the population structure, - including allelic and heterozygosity frequencies - of B. thompsonii and B. formosa …
Phylogenetic Relationships Of Purshia Tridentata And Cowania Mexicana, Stewart C. Sanderson
Phylogenetic Relationships Of Purshia Tridentata And Cowania Mexicana, Stewart C. Sanderson
Theses and Dissertations
Because of the greatly increased supply of genetic variation which it provides, introgression is of great importance in determining both the rate and the direction of evolution. Hybridization between the genera Cowania and Purshia provides an excellent model for demonstrating the various products which might be expected from introgression. The present study is an attempt to further investigate phylogenetic relationships of Cowania mexicana and Purshia tridentata by use of cytological and biochemical techniques.
Cytological Evidence For Reciprocal Introgression In Agropyron Trachycaulum And Agropyron Spicatum, Laval M. Pitts
Cytological Evidence For Reciprocal Introgression In Agropyron Trachycaulum And Agropyron Spicatum, Laval M. Pitts
Theses and Dissertations
Agropyron trachycaulum (Link) Malte and Agropyron spicatum Pursh, both native range grasses of the Great Basin, often hybridize in nature. A. trachycaulum, is a tetraploid with 28 chromosomes. It has awnless or awntipped lemmas and small anthers. A. spicatum is a diplois with 14 chromosomes. It is characterized by having long awn that bend at maturity, and anthers which are about four times longer than A. trachycaulum. Artificial hybrids are intermediate between parents in awn and anther lengths and have 21 chromosomes. A natural population in Utah was found consisting of A. trachycaulum, A. spicatum, plants resembling the artificial hybrids, …