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Dissertation Information for Karl William Hillig

NAME:
- Karl William Hillig

DEGREE:
- Ph.D.

DISCIPLINE:
- Biology

SCHOOL:
- Indiana University (USA) (2005)

ADVISORS:
- Keith Clay
- Jeffrey Palmer
- Paul Mahlberg
- Gerald Gastony

COMMITTEE MEMBERS:
- None

MPACT Status: Incomplete - Not_Inspected

Title: A systematic investigation of Cannabis

Abstract: Botanists disagree whether Cannabis (Cannabaceae) is a monotypic or polytypic genus. A systematic investigation was undertaken to elucidate underlying evolutionary and taxonomic relationships within the genus. Genetic, morphological, and chemotaxonomic analyses were conducted on 157 Cannabis accessions of known geographic origin. Sample populations of each accession were surveyed for allozyme variation at 17 gene loci. Principal component (PC) analysis of the allozyme allele frequencies revealed that most accessions were derived from two major gene pools corresponding to C. sativa L., and C. indica Lam. A third putative gene pool corresponds to C. ruderalis Janisch. Previous taxonomic treatments were tested for goodness of fit to the pattern of genetic variation. Based on these results, a working hypothesis for a taxonomic circumscription of Cannabis was proposed that is a synthesis of previous polytypic concepts. Putative infraspecific taxa were assigned to "biotypes" pending formal taxonomic revision. Genetic variation was highest in the hemp and feral biotypes and least in the drug biotypes. Morphometric traits were analyzed by PC and canonical variates (CV) analysis. PC analysis failed to differentiate the putative species, but provided objective support for recognition of infraspecific taxa of C. sativa and C. indica . CV analysis resulted in a high degree of discrimination of the putative species and infraspecific taxa. Variation in qualitative and quantitative levels of cannabidiol (CBD), tetrahydrocannabinol (THC), and other cannabinoids was determined, as were frequencies of alleles that control CBD and THC biosynthesis. The patterns of variation support a two-species concept, but not recognition of C. ruderalis as a separate species from C. sativa . PC analysis of terpenoid variation showed that the wide-leaflet drug (WLD) biotype of C. indica produced enhanced mean levels of guaiol and isomers of eudesmol, and is distinct from the other putative taxa. In summary, the results of this investigation show that a taxonomic revision of Cannabis is warranted. However, additional studies of putative wild populations are needed to further substantiate the proposed taxonomic treatment.

MPACT Scores for Karl William Hillig

A = 0
C = 0
A+C = 0
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2010-09-22 20:06:06

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