Testing the Applicability of MALDI-TOF MS as an Alternative Stock Identification Method in a Cryptic Species Complex

Abstract

Knowledge of intraspecific variability of a certain species is essential for their long-term survival and for the development of conservation plans. Nowadays, molecular/genetic methods are the most frequently used for this purpose. Although, the Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) technique has become a promising alternative tool to specify intraspecific variability, there is a lack of information about the limitations of this method, and some methodological issues need to be resolved. Towards this goal, we tested the sensitivity of this method on an intraspecific level, using genetically identified individuals of a cryptic fish species complex collected from five distinct populations. Additionally, some methodologic issues, such as the effect of (1) delayed sample preparation, (2) clove oil anaesthetization, and (3) different tissue types (muscle, and brain) were investigated using the MS analysis results. Our results show that the delayed sample preparation has a fundamental effect on the result of MS analysis, while at the same time the clove oil did not affect the results considerably. Both the brain and muscle samples were usable for cryptic species identification, but in our opinion this method has limited applicability for population-level segregation. The application of MALDI-TOF MS to the exploitable toolkit of phylogenetic and taxonomic researches could be used to broaden conclusions.

Recent speciation and hybridization in Icelandic deep‐sea isopods: An integrative approach using genomics and proteomics

“…We interpret the high similarity between the different H . bicuspis species found in this study as a reflection of recent or ongoing speciation processes, as reported in fishes (Maasz et al, 2020; Takács et al, 2014). It is likely that young species are both morphologically and physiologically cryptic, revealing the limit of proteomic fingerprinting for species identification in such instances.…”

“…Thus, it remains unanswered whether the higher similarity of putative species IV and V results from very similar environmental impacts and thus comparable selection pressures in the past causing a similar physiological response. We interpret the high similarity between the different H. bicuspis species found in this study as a reflection of recent or ongoing speciation processes, as reported in fishes (Maasz et al, 2020;Takács et al, 2014). It is likely that young species are both morphologically and physiologically cryptic, revealing the limit of proteomic fingerprinting for species identification in such instances.…”

Recent speciation and hybridization in Icelandic deep-sea isopods: an integrative approach using genomics and proteomics

“…We interpret the high similarity between the differentH. bicuspis species found in this study as a reflection of recent or ongoing speciation processes, as reported in fishes (Takács et al, 2014, Maasz et al, 2020. It is likely that young species are both morphologically and physiologically cryptic, revealing the limit of proteomic fingerprinting for species identification in such instances.…”

Integrative Description of Cryptic Tigriopus Species From Korea Using MALDI-TOF MS and DNA Barcoding

“…Until now, various factors which could affect difference in spectra such as fixative solution and storage period after fixation have been investigated (Rossel and Martínez Arbizu, 2018). Usefulness of MALDI-TOF MS in cryptic species identification such as bacteria, mosquitoes, fish and sandflies have also been documented (Müller et al, 2013;Dieme et al, 2014;Paauw et al, 2015;Chavy et al, 2019;Maasz et al, 2020). This study further expands on the usefulness of MALDI-TOF MS, confirming that higher-resolution species identification (identification of cryptic species) is possible for copepods as well.…”