التفاصيل البيبلوغرافية
| العنوان: |
Characterizing the phylogenetic distribution of cryptic species in the Rhodophyta using novel gene sequence analysis and molecular morphometrics |
| المؤلفون: |
Lynch, Michael |
| سنة النشر: |
2011 |
| المجموعة: |
Theses Canada / Thèses Canada (Library and Archives Canada) |
| مصطلحات موضوعية: |
Rhodophyta, Bangiales, nSSU rRNA, taxonomy, cryptic species, phylogenetics, Florideophyceae, Biology |
| الوصف: |
The Rhodophyta (red algae) are an ancient crown group of the Eukarya (ca. 1400-1500 million years), comprised of 5000 - 6000 species. Gametophytes of taxa excluding the speciose Class Florideophyceae are typically of very simple unicellular, filamentous or foliose morphologies. These simple morphologies are often homoplasious (resulting from convergent or parallel evolution) and can be indistinguishable among distinct taxa, leading to cryptic species. As a result, historical morphology-based taxonomy is often not congruent with evolutionary history. Intraspecific genetic variation is not yet characterized for non-Florideophyceae taxa. Here the intraspecific genetic variation was characterized for a locally endemic, morphologically distinct bangiophyte red alga, Bangia maxima Gardner using inter simple sequence repeat (ISSR) patterns from 91 individual filaments across seven local populations. A high degree of genetic variation was observed over very small distances (< 25 cm) and very little genetic exchange was observed between populations. It is possible that B. maxima is a true endemic species and its population dynamics may differ from other Bangia species. Metrics of sequence-based identification rely on genetic divergence among isolates to distinguish taxonomic units independent of morphology. Such metrics are especially useful for morphologically simple or cryptic species. The mitochondrial cytochrome oxidase c subunit 1 gene has been proposed for the Florideophyceae. An evaluation of this gene as a metric for non-Florideophyceae taxa was undertaken and limited utility was demonstrated in most lineages of Rhodophyta due to poor or inconsistent amplification and conflicts with nuclear and plastid phylogenies. Patterns of genetic divergence among taxa are used to infer evolutionary relationships. The nuclear ribosomal small subunit (nSSU rRNA) is the taxonomically broadest pool of gene sequence data for the Rhodophyta. The use of stochastic models of nucleotide evolution is the most common approach to ... |
| نوع الوثيقة: |
thesis |
| اللغة: |
English |
| العلاقة: |
http://hdl.handle.net/10012/5943Test |
| الإتاحة: |
http://hdl.handle.net/10012/5943Test |
| رقم الانضمام: |
edsbas.E80C8E81 |
| قاعدة البيانات: |
BASE |
