Determination of intra-specific genetic
diversity in butterfly weed (Asclepias tuberosa L.) using ISSR-PCR
L., the butterfly weed, has become a desirable horticultural plant due
showy orange-red flowers, its ability to attract butterflies, and its
to grow in a variety of soils. Its
roots have also been used as a traditional medicine to treat a number
pulmonary ailments. Recent attention
has been put on this plant because butterflies, including the famous
butterfly, lay their eggs on the underside of the leaves, and the
on the leaves for food and protection. The co-evolution of the two
such that monarch butterflies incorporate the secondary metabolites
the butterfly weed into their own defense against predators. Asclepias
tuberosa has the same range as that of the monarch butterfly and is
in the greater part of the contiguous United States.
Unfortunately, native stands of the plant are disappearing in
York State such that the plant is now protected under New York State
law. The purpose of this population
project is to determine whether or not native stands of Asclepias
tuberosa in Westchester County, NY, are genetically
distinct from plants found elsewhere in the United States.
The study’s aim is to determine whether it
is necessary to protect native stands, or allow for reintroduction of
weed using seeds from plants outside of New York State.
In order to determine genetic diversity
within this species, we have isolated or will isolate DNA from a number
samples from Westchester County and specific areas in the United
well as from plants obtained from seed catalogs. We
have begun analyzing the DNA by using inter-simple specific
repeat (ISSR) markers. This PCR-based
technique, like many techniques analyzing DNA, relies on polymorphisms
repeat sequences of the genomes of the organisms being studied. ISSR’s have been used to investigate
evolutionary relationships among different species within a genus. We are using this technique, however, to
relationships within a single species.
Thus far, polymorphisms have been detected among the various
within even a single population of plants.
We are in the process of analyzing 60 different DNA samples of
weed for ISSR polymorphisms. Early
results from the ISSR analysis will be presented and discussed. The research also includes taking a survey
of the population distribution, density, and flower color diversity at
Westchester County, focusing on a protected meadow.
Results of the population distribution of the butterfly weed in
the meadow show a large number of individuals that are able to thrive
protected area. There also seems to be
a great diversity in flower color, suggesting large genetic diversity. This suggests that one of the ways to
maintain a critical number and diversity of butterfly weed plants in
State is to maintain protected areas and sanctuaries.