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Full-Text Articles in Plant Sciences
Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon
Theses and Dissertations
Species range margins are often characterised by high degrees of habitat fragmentation resulting in low genetic diversity and higher gene flow from populations at the core of the species range. Interspecific gene flow from a closely related species with abutting range margins can increase standing genetic diversity and generate novel allelic combinations thereby alleviating limits to adaptive evolution in range margin populations. Hybridization driven interspecific gene flow has played a key role in the demographic history of several conifer due to their life history characteristics such as weak crossability barriers and long generation times. Nevertheless, demonstrating whether introgression is adaptive …
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, …