Undergraduate Honors Thesis Projects

Date of Award

Spring 4-26-2024

Document Type

Honors Paper

Degree Name



Biology & Earth Science


Dr. Jeffrey Lehman

First Committee Member

Dr. Brandon Sinn

Second Committee Member

Dr. Margaret Kohler


Ginkgo, molecular methods, sex determination, MADS-box genes

Subject Categories

Molecular Genetics


Ginkgo biloba L. (GINKGOACEAE) is one of the oldest known tree species and is the sole representative of the monotypic genus Ginkgo. Ginkgo trees are dioecious (i.e., separate, individual male and female trees) and take >20 years to reach sexual maturity. Female trees produce a seed enclosed in the fleshy and fruit like sarcotesta that emits a putrid smell when mature. Because of the smell, male trees are preferred in urban settings. The ginkgo industry propagates trees clonally via grafting or stem cuttings to insure male plants at the expense of genetic diversity. In contrast, female ginkgo trees have been reported to produce higher levels of pharmaceutically relevant flavonoids; hence, genetically diverse female populations of ginkgo are an interest to the pharmaceutical industry. This study aimed to develop a method to accurately determine the sexual identity of ginkgo seedlings with a PCR-based approach. The methods are based on the amplification of a 1,030-bp sex determining region of GbMADS18 located on chromosome 2. The reliability of the PCR-based sex marker was confirmed with eight mature female and four mature male individuals whose sexual identity was determined phenotypically. The PCR-based approach was then used to screen a population of 30 seedlings for sexual identity. Based on the presence/absence of the 1,030 bp band, the population was comprised of 12 males and 18 females and did not differ from an expected 1:1 ratio of males to females (X2 = 1.2, df=1). These results indicate that a molecular determination of sexual identity based on the amplification of GbMADS18 gene correlates with phenotypic sexing of mature ginkgo trees and can predict the sexual identity of immature seedlings.

Licensing Permission

Copyright, all rights reserved. Fair Use

Acknowledgement 1


Acknowledgement 2


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