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Lecture 1 - September 10, 2013 - LIFESCI 2A03

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Life Sciences
Joe Kim

LIFESCI 2A03 Lecture 1 September 10, 2013 Research Methodologies in the Life Sciences  Science is about ideas, and because the unifying ideas [of science] are in constant need of revision as new facts come to light, and the insight of new ideas redefines the implications of the old knowledge, we can never “know enough” – New Scientist, 1985  Scientific journals are published to share scientific knowledge with the scientific community – people can disagree and do research contrary to a study; people can agree and further the research Characteristics of Science 1) Science is based upon empirical knowledge (not just a hypothesis; based on observation and data) o Observations that are made – often the starting point of a scientific investigation o Eg/ Regenerating a limb – a newt can regenerate an entire limb within 7-10 weeks  Compare processes, chemicals, biological knowledge 2) Commitment to rationality/natural explanations o Seeking explanations in terms of natural causes; understand the cells, what proteins, which genes are involved in this process o Rational explanation, regardless of biases that we have o Eg/ Regeneration is not miraculous; there is a biological explanation and this phenomenon is studied 3) Repeatability and reliability o Scientific results are always subject to confirmation by other investigators o Not necessarily simply that it is repeated with the same results, but that it can be repeated reliably by other scientists o Methods in scientific journals – not only to do the same study; also to rely on the data and to further results and study o If same experiment is not repeatable or has different results – something must be wrong o Eg/ Loch Ness Monster – observations lack reliable confirmation 4) Testability o A neat theory is not sufficient – must be testable through experimentation o Must directly test hypothesis – if not testable, hypothesis only a myth o Eg/ Regeneration of salamanders – proposed that this required pluripotent stem cells (like embryonic stem cells)  Reported recently that severed limb may not need pluripotent stem cells to regenerate, but only multipotent or unipotent stem cells, stem cells with relatively restricted fates  Stem cells are cells that can become other types of cells (bone, muscle etc) 1 LIFESCI 2A03 o Pluripotent – able to become any type of cell o Multipotent – many potential cells; can become many different cells o Unipotent – potential to become one type of cell  Test stem cells – find them, do they exist? Are they essential for regeneration? (remove or add more – see observations) 5) Commitment to the use of experimentation o Planned intervention into a natural process to observe the effects o Eg/ A Limb Regeneration Mystery Solved  Labeling cells and observing fate – can differentiate labeled cells (eg/ stem cells) from other cells  Can determine whether stem cells were able to become bone cells, muscle cells, other cells or more than one 6) Generality of principles o The search for generality; the establishment of principles that operate throughout the natural world o Biologists are interested in understanding living processes in all organisms o Eg/ Salamander find to help human tissue regeneration studies o Can these principles apply to all mammals? Only to a single organism? Scientific Method  Often outlined in some sort of flow chart or list 1) Define/Identify the Problem 2) Form a Hypothesis 3) Test Hypothesis – make observations or perform experiments 4) Organize and Analyze Data 5) Do Experiments and Observations Support Hypothesis? a. If no – perform new experiments and analysis 6) Draw Conclusions 7) Communicate results Case Study – Human Chromosome Count  Theophilus Painter, 1923 – reported that there were 48 chromosomes in a human cell o Serial sections of testicular cells in metaphase o Figure 1: Human spermatogonial metaphase in a mitotic cell
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