Josh Andersen and Dr. Daniel Fairbanks, Botany and Range Science
While much is known of the genetic mechanism of sex determination in mammals, very little is known of similar mechanisms in plants. Sex determination in plants may be either environmental or genetic. Dioecious plant species, such as Atriplex Garrettii (Chenopodiaceae), offer researchers an ideal situation in which to study sex determination and compare genetic differences between individuals. Female and male A. garrettii are consistently observed in a 1:1 ratio, which strongly suggests genetic sex determination. Also, when comparing karyotypes between female and male A. garrettii, no apparent chromosomal differences can be seen, suggesting sex determination could be due to one or a group of genes located on autosomal chromosomes. Research done by Ruas et. al (1998) at Brigham Young University confirmed the existence of a male-specific DNA marker in A. garrettii. The marker was then isolated and sequenced. In comparing the sequence to others, researchers found, embedded within the gene, sequences homologous to the Antirrhinum majus centroradialis (cen) gene involved in floral development. This evidence suggests that the male-specific fragment could play a role in sex determination in A. garrettii.
The aim of our research was to design special primers to expand on, and analyze the original marker found by Ruas et. al (1998). We succeeded in amplifying a band with our custom-designed primers but sequencing efforts revealed inconsistencies in its sequence compared to the original marker. It appeared that we had amplified part of the plasmid that contained our DNA fragment. We tried the protocol again several times with no success. At that point, the project leader took a leave of absence from school and I took on teaching assistant responsibilities for Dr. Fairbanks which occupied most of my time.
As a result of my efforts, I became more familiar with many useful lab techniques such as cloning, PCR analysis, and primer design, which have proven very useful in my experience as a graduate student. This project has enormous potential to possibly elucidate a mechanism of sex determination in plants and I anxiously look forward to its fulfillment.