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Population genetics of the
rare nettle Hesperocnide sandwicensis
and its widespread sister species Hesperocnide tenella
Jane Mygatt
Department of Biology
University of New Mexico
Albuquerque, N.M. 87131
The evolution of organisms after long-distance dispersal is and important
phenomenon in biology. Newly evolving species and the study of their genetic
variation are of particular interest in evolutionary and conservation biology
where the amount of heritable variation can effect the fitness and viability
of populations. Comparing the genetic variation of widespread versus rare species
will provide important information on the relative genetic health of the species.
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The coast nettle (Hesperocnide
tenella) on Catalina
© 1997 Frank Starkey |
The evolution of organisms after long-distance dispersal is and important phenomenon
in biology. Newly evolving species and the study of their genetic variation are
of particular interest in evolutionary and conservation biology where the amount
of heritable variation can effect the fitness and viability of populations. Comparing
the genetic variation of widespread versus rare species will provide important
information on the relative genetic health of the species.
My thesis research focuses on the systematic and evolutionary botany, with
a specialization in the conservation biology and population genetics of the western
nettle, Hesperocnide, (Urticaceae) a genus of only two species. I will
measure how much genetic variation exists in natural populations of these two
closely related species: the relatively widespread Californian nettle Hesperocnide
tenella Tor., and the narrowly distributed Hawaiian nettle Hesperocnide
sandwicensis (Wedd.) Wedd. I want to confirm the close evolutionary relationship
of these two species and investigate the population genetics of the Hawaiian
nettle, which is being proposed for Federal protection under the Endangered Species
Act.
My hypothesis is that the Hawaiian nettle is derived from the Californian
nettle. The restricted distribution of the Hawaiian species may indicate a relatively
recent (i.e.<1,000 years), long-distance dispersal event from the California
coast. It has been often reported that recently evolved species typically have
lower levels of genetic variation than do geographically widespread species.
Being closely related, the two species should have a high degree of similarity
in their genetic composition, although the Hawaiian nettle (being the presumed
derived species) should contain less variation overall.
Goals of this study are to: 1) determine whether the two species of Hesperocnide are
genetically and morphologically distinct; 2) asses the amount of genetic variation
within populations of H. sandwicensis compared to H. tenella;
3) employ protein electrophoretic analyses to explore the origins of and genetic
variability in H. sandwicensis, a proposed endangered species on the
big island of Hawaii; 4) contribute information on the evolution of organisms
after long distance dispersal, and; 5) contribute information useful for the
design of conservation management programs. |
