U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Northeast Area Beltsville, Maryland (BARC) Beltsville Agricultural Research Center Sustainable Perennial Crops Laboratory Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Emche, Stephenitem
                                            Zhang, Dapengitem
                                            ISLAM, MELISSA - University Of Coloradoitem
                                            Bailey, Bryanitem
                                            Meinhardt, Lyndel
  Submitted to: Tropical Plant Biology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 1/20/2011
                                    Publication  Date: 5/16/2011
                                    Citation: Emche, S.D., Zhang, D., Islam, M.B., Bailey, B.A., Meinhardt, L.W. 2011. AFLP Phylogeny of 36 Erythroxylum species- genetic relationships among Erythroxylum species inferred by AFLP analysis. Tropical Plant Biology. 4(2):126-133.Interpretive Summary: Cocaine is an illicit narcotic alkaloid that is produced in plants in the genus Erythroxylum. There are many wild species of Erythroxylum and we don’t know how they are related to each other genetically, geographically or taxonomically. We analyzed the DNA of two cocaine producing species (that are grown for illicit markets) and 33 other wild species to determine how they are related to each other. We found all of the Erythroxylum species separated into three main groups that corresponded to their geographical origin. We also found that the cocaine producing Erythroxylum species are more closely related to each other than to any other species. This is the largest genetic analysis of Erythroxylum. The analysis of these species will provide new information to researchers and government agencies to assist and improve control measures of illicit coca cultivation. In addition this information will improve our understanding of this plant and it’s worldwide distribution.
                                Technical Abstract: The plant genus Erythroxylum is known for four cultivated taxa, Erythroxylum coca var. coca (Ecc), Erythroxylum coca var. ipadu (Eci), Erythroxylum novogranatense var. novogranatense (Enn) and Erythroxylum novogranatense var. truxillense (Ent) that are cultivated primarily for the illicit extraction and processing of cocaine. Despite their economic and medical importance, the evolutionary history of the cultivated species and their closest non-cultivated relatives remains unknown and untested in a modern phylogenetic framework. The aims of this study were to (a) to investigate the relationship among the cultivated taxa and their non-cultivated relatives, and (b) to test the hypothesis of linear progression of the cultivated taxa (Ecc'Ent'Enn) versus the second hypothesis that Ec and En are sister species. Phylogenetic analysis based on 886 AFLP polymorphic fragments was used to compare the relationships among the cultivated taxa and their non-cultivated relatives for 35 Erythroxylum species (132 accessions) spanning the geographic distribution of the genus. Multivariate ordination analysis was used to evaluate the relationship between cultivated and non cultivated taxa from the tropical Americas. A Maximum Parsimony tree constructed for the 35 Erythroxylum species revealed three major clades that represent Africa, Asia-Pacific and the New World species. A small cluster of non-cultivated species was revealed as the most closely related to the cultivated Erythroxylum species. In addition, Ec and En formed distinct, parallel subclades. Our results support the hypothesis that the cultivated species are more closely related to each other than to any other species of Erythroxylum but refute the hypothesis that En descended from Ec. Instead our data suggest an independent, non-linear evolutionary relationship between Ec and En.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov