Evolutionary Factors Contributing to Genetic Differentiation between Subpopulations of Raphanus Raphanistrum
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Authors
Howe, Stephen R.
Issue Date
2004
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
The plant species Raphanus raphanistrum has been demonstrated to have
phenotypic differences between populations located through out the world. A previous
study proved that the majority of these phenotypic differences were due to genetic
differentiation between populations. In this study, I used Fst and, Qst techniques to
analyze these same traits in order to determine if the genetic differences were caused by random genetic drift or by differential natural selection, as well as to determine if the
genetic similarities were caused by convergent natural selection. To do this, I grew
plants from seven populations around the world in a greenhouse. I measured and
analyzed thirteen traits during the experiment to determine if significant differences were
present, and then combined the data with parental data to produce Qst values for each
trait. I also analyzed suspected neutral sites in the genome to produce Fst values. The
average Fst value was found to be 0.115. No Qst value fell within two standard errors of this value, implying that none of the differences was caused solely by genetic drift. The
height of the first flower, corolla tube length, number of ovules produced, stamen
dimorphism, time to germination, time from germination to flowering, anther exertion,
long anther length and short anther length were all found to have Qst values significantly higher than the mean Fst value, implying they underwent divergent selection. Short filament length, long filament length and pistil length all had smaller QstT values than the mean Fst value, implying they underwent convergent selection.
Description
iii, 30 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.