The oxidation of biogenically emitted dimethyl sulfide (DMS, CH_3SCH_3) serves as the major source of sulfur in the remote marine atmosphere. The DMS oxidation pathways are highly complex and uncertain, and lead to a large number of products: SO_2, dimethyl sulfoxide (DMSO, CH_3S(O)CH_3), dimethyl sulfone (DMSO_2, CH_3S(O)_2CH_3), methanesulfenic acid (MSEA, CH_3SOH), methanesulfinic acid (CH_3S(O)OH, MSIA), methanesulfonic acid (MSA, CH_3SO_3H), and H_2SO_4. Some of these products are capable of creating new or altering existing tropospheric aerosols, which has driven much of the research aimed at reducing the uncertainties in the DMS oxidation mechanism. This report uses a combination of simultaneous observations from the ACE 1 measurement campaign and a time-dependent model of detailed DMS oxidation chemistry and vertical mixing to study the oxidation paths and branches in an effort to reduce the DMS mechanism uncertainties. The model components include self-consistent eddy-diffusion coefficients for vertical mixing, chemical production and loss of 28 sulfur-related species specified through 55 chemical reactions, condensational loss of soluble species on background aerosols, and ocean surface emissions and dry deposition. The model is driven by a diurnal OH profile that was fit to {\it in situ} high-frequency ACE 1 observations. Other observationally-based inputs include vertical profiles of temperature, pressure, relative humidity, ozone, peroxides, and aerosol size distributions. Several thousand Monte Carlo runs of the model using uncertainty estimates of the model inputs define the probability distribution functions (PDFs) of the output observables. By comparison of the model PDFs with ACE 1 observations of SO_2, MSA, and H_2SO_4, this report shows, that within the mechanism uncertainties, the current mechanistic picture of DMS oxidation is lacking critical branches and reactions. To resolve these statistically significant model-observation differences, six new sets of reactions are proposed. These new reactions include the oxidation of MSEA and MSIA, and isomerizations of key sulfur-centered radicals. These proposed reactions and their impact on DMS oxidation chemistry and product distributions are presented, along with possible methods to discern the proposed pathways through field or laboratory measurements.