Document Type

Collaborative Scholarship


As ecologists increasingly employ molecular methods, they find that tried and true preservation solutions (e.g. ethanol or formalin) may not be optimal when samples are targeted for genetic analyses. Before traveling to remote sample sites, researchers need to consider which preservation methods are likely to yield the largest quantity and highest quality of DNA based on their travel times and field conditions. They also need to consider whether they will have access to preservatives at remote sites and whether those preservatives can be safely transported. To determine which preservation methods would most reliably preserve tissue for genetic analysis under a range of field conditions, we examined total DNA recovery from female fruit flies (Drosophila melanogaster) individually held in various solutions (70% ethanol; 2% SDS, 100 mM EDTA; 1% SDS, 50 mM EDTA; 0.66% SDS, 33 mM EDTA; Zymo© lysis buffer; Zymo Xpedition© lysis buffer) at three different temperatures (22oC, 4oC and -20oC) for varying lengths of time (1 day, 4 weeks, and 8 weeks). We predicted that insects held in Zymo Xpedition© buffer would yield the overall highest DNA recovery since this buffer was designed for field collected animal tissue. We also predicted that variation in DNA recovery from insects held in different solutions would increase with preservation time and holding temperature. Although we observed significant differences in total DNA recovery from some of our samples, no trends were identified. Preliminary band quality analyses of PCR products utilizing stored DNA as template for amplification of the mCOI gene generally indicated decline in product quality as storage time increased. Future work will focus on better quantifying stored DNA quality and examining the relationship between total DNA recovered and overall DNA quality.

About the Author

Authors Alison Schutt, Emily Stricklin, Britta Ten Haken, and Joseph Tolsma are currently students at Northwestern College.

An environmental scientist, Dr. Furlong holds a doctorate in ecology, evolution and marine biology. Her research and publications have been in the fields of stream ecology, entomology and biogeography, and she has experience as a biological consultant. Furlong teaches Introduction to Environmental Science, General Biology, Invertebrate Zoology and Aquatic Ecology. She has also been a stream ecology instructor for the Creation Care Study Program in Belize.

Dr. Tolsma’s research efforts in cancer genetics and cell biology have been widely published in scientific journals and have received a number of awards. A Northwestern College alumna, she holds a doctorate in microbiology/immunology/virology from Northwestern University. During a sabbatical, she worked on a cell and molecular genetics textbook for non-science majors, as well as an adult Sunday school curriculum on genetic technologies. She has been a part of several symposia on bioethical issues surrounding genetic technologies, such as stem cells, cloning and genetic testing. Her current laboratory research extends her interest in genetics to populations in a study of mayfly genetic variation in Northwest Iowa watersheds and her interest in cancer cell biology with a project that measures the anti-proliferative effects of plant extracts and chemicals in those extracts on human tumor cells in vitro. She is the 2015 recipient of Northwestern's annual Teaching Excellence Award.



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