[1] In 1995, George Palade and Marilyn Farquhar (among others) recruited Marth to the University of California, San Diego (UCSD) in the Department of Cellular and Molecular Medicine.
[16] Marth's use of Cre-Lox conditional mutagenesis established the presence and functions of multiple and in some cases previously unknown enzymes participating in protein glycosylation, an area of research that has become a focus of exploration of the genetic and metabolic origins of disease.
[19] Marth's early studies of glycosylation and glycan linkages revealed a profound effect on immunity and contributed to the genesis of the related sub-field termed glycoimmunology.
[23][24] Their research demonstrated that acquired pancreatic beta cell dysfunction was the major contributor of disease onset and corroborated views that genetic variation was unlikely to be the primary cause of obesity-associated Type 2 diabetes in humans.
[3] In 2008, Marth published an initial enumeration of the building blocks of life, all of which fall under the four types of cellular macromolecules (glycans, lipids, nucleic acids, and proteins).
Marth and other colleagues have called attention to the fact that only half of these macromolecules are encoded by the genome, suggesting that a more holistic approach is needed in biomedical research to fully understand and intervene in the origins and progression of disease.