Examining Epistatic and Environmental Effects Using an Alternative Formaldehyde Oxidation Pathway in Methtylobacterium Extorquens
W33
Abstract
Epistasis is the interaction of genes, particularly how the presence of a gene locus modifies the phenotype of other loci. Previous research in the lab studied the epistatic interactions of beneficial mutations that arose in an evolved isolate of Methylobacterium extorquens, a bacteria that has the ability to utilize one-carbon compounds as the sole source of energy. Four mutations were identified following the replacement of the methanopterin-dependent pathway of M. extorquens’ with a glutathione (GSH)-dependent pathway from Paracoccus denitrificans. The mutations were combined in all viable permutations on a genetic background that only contained the GSH-dependent pathway. We tested the fitness of each strain against the ancestral evolved isolate under two minimal media growth conditions: Hypho in flasks, the condition under which the original study that identified the mutations was conducted, and MPIPES, a more complete media, in sealed Balch tubes in which future experimental work will be performed. We expect to see similar epistatic interactions with diminishing returns as the original study found, suggesting minimal effect of these media conditions on epistasis. By better understanding gene-gene interactions in this system, we hope to lead to models capable of predicting adaptive routes through fitness landscapes underlying M. extorquens physiology.
Examining Epistatic and Environmental Effects Using an Alternative Formaldehyde Oxidation Pathway in Methtylobacterium Extorquens
Epistasis is the interaction of genes, particularly how the presence of a gene locus modifies the phenotype of other loci. Previous research in the lab studied the epistatic interactions of beneficial mutations that arose in an evolved isolate of Methylobacterium extorquens, a bacteria that has the ability to utilize one-carbon compounds as the sole source of energy. Four mutations were identified following the replacement of the methanopterin-dependent pathway of M. extorquens’ with a glutathione (GSH)-dependent pathway from Paracoccus denitrificans. The mutations were combined in all viable permutations on a genetic background that only contained the GSH-dependent pathway. We tested the fitness of each strain against the ancestral evolved isolate under two minimal media growth conditions: Hypho in flasks, the condition under which the original study that identified the mutations was conducted, and MPIPES, a more complete media, in sealed Balch tubes in which future experimental work will be performed. We expect to see similar epistatic interactions with diminishing returns as the original study found, suggesting minimal effect of these media conditions on epistasis. By better understanding gene-gene interactions in this system, we hope to lead to models capable of predicting adaptive routes through fitness landscapes underlying M. extorquens physiology.