Honeybee Paper Assignment
Mary Beth Putz
5 May 2015
Honeybee Paper Assignment The paper, Nutritional Control of Reproductive Status in Honeybees via DNA Methylation, discusses the relatively unique case of female honeybees, where although they have identical DNA sequences, there are queen bees and worker bees, with very distinct phenotypes. The research team began with the observation that females bees who are fed royal jelly while a larvae become queen bees, while females not fed royal jelly become normal worker bees. The research team then worked from the hypothesis that there is something in royal jelly that when eaten, epigenetically affects methylation of DNA in the female so that there is lowered methylation, which in turn leads to higher gene expression and likely the phenotype of the queen bee. They tested this hypothesis with a few specific predictions. The first was to test whether or not RNAi (RNA interference technology) was working and actually blocking expression. This was carried out by injecting Dnmt3 siRNA into newly hatched larvae and observing that the amount of Dnmt3 mRNA was lower in those individuals than in the control group. The second experiment was to test the prediction that when treated with Dnmt3 siRNA, there would be an increase in the number of queens produced. This was tested by comparing larvae injected with the Dnmt3 siRNA and other larvae injected with a control gene siRNA, uth. Results showed that when injected with the Dnmt3 siRNA, the majority of emerging adults were queens (72%), while in the control condition, only 23% exhibited queen-like structures. Finally, the research team examined their prediction that there would be less methylated DNA in the bees treated with the Dnmt3 siRNA specifically in the larval heads because the heads have the most relevant tissues to developmental processes such as brain neurosecretory cells and corpora allata. They did in fact find that in comparison to the control, there was a significant decrease in overall
5 May 2015
Honeybee Paper Assignment The paper, Nutritional Control of Reproductive Status in Honeybees via DNA Methylation, discusses the relatively unique case of female honeybees, where although they have identical DNA sequences, there are queen bees and worker bees, with very distinct phenotypes. The research team began with the observation that females bees who are fed royal jelly while a larvae become queen bees, while females not fed royal jelly become normal worker bees. The research team then worked from the hypothesis that there is something in royal jelly that when eaten, epigenetically affects methylation of DNA in the female so that there is lowered methylation, which in turn leads to higher gene expression and likely the phenotype of the queen bee. They tested this hypothesis with a few specific predictions. The first was to test whether or not RNAi (RNA interference technology) was working and actually blocking expression. This was carried out by injecting Dnmt3 siRNA into newly hatched larvae and observing that the amount of Dnmt3 mRNA was lower in those individuals than in the control group. The second experiment was to test the prediction that when treated with Dnmt3 siRNA, there would be an increase in the number of queens produced. This was tested by comparing larvae injected with the Dnmt3 siRNA and other larvae injected with a control gene siRNA, uth. Results showed that when injected with the Dnmt3 siRNA, the majority of emerging adults were queens (72%), while in the control condition, only 23% exhibited queen-like structures. Finally, the research team examined their prediction that there would be less methylated DNA in the bees treated with the Dnmt3 siRNA specifically in the larval heads because the heads have the most relevant tissues to developmental processes such as brain neurosecretory cells and corpora allata. They did in fact find that in comparison to the control, there was a significant decrease in overall