History and Basic Concepts Model Organisms
Prof. Tylzanowski
Themes/Questions
Biomedical research needs tools that would permit efficient disease study and exploration of curative
strategies. Not all problems can be addressed in an organism-free context. The class will explore
several animal proxies of humans and explore the advantages and limitations of these models. Some
alternatives to animals will be presented with the advantages and limitations as well (the last class).
- What is the best animal model to study humans?
- Am I really like a fruit fly?
- What are the scientific basis supporting use of animals in biomedical research?
Biomedicine: “We don’t cure patients, we cure diseases.”
Challenges and solutions in medicine today
- Challenge: molecular basis of disease processes.
- Solutions?
Developmental process at wrong place/time?
Cancer, metastasis, etc.
Short view on history of Developmental Biology
Descriptive studies of change: Take 20 eggs or more and give them to 2 or 3 hens to incubate, then
each day from the second onwards till the time of hatching take an egg, break it, and examine it (the
first account by Hippocrates).
See workshops!
Lots of progress got halted as Christianity being ever more dominant, grinding science to a halt.
- Performation theory: The organism is preformed as a complete miniature structure in the
egg and simply grows larger as it develops. People that support this idea were called ‘Ovists’.
- Theory of homunculus: suggested that a little human embryo (homunculus) was hidden in
the head of every sperm. People that support this idea were called ‘homunculists’ or
‘spermists’.
Leonarde Da Vinci: dissection of the human fetus and quantitative measurement of embryonic
growth. First to give evidence that embryos change in weight, size and shape over time.
Andreas Vesalius: first described the human placenta.
Marcello Malphigi: study structures such as lungs, kidneys, spleen, brain and skin. First microscopic
account of chick development. Concluded that egg contained miniature chick. Responsible for rise of
preformationist doctrine.
Recapitulation theory EXAM!
Also called biogenetic law, states that ontogeny repeats phylogeny. Means developmental stages of
higher animals closer resemble the adults of their ancestral species. Throughout development we re-
run things that have happened => evolution. => why we use animals in research.
,Experimental models
- Mathematical models computer simulations
- Non-living mechanical or molecular systems biochemistry
- Living systems composed of samples from the original animal tissue or organ culture
- Whole living animals human and non-human
o No research on humans but nature does it for us. Mutation gives different
phenotype.
, Rationale…
- Physiological relevance highest on right
- Experimental traceability highest on left
See separate lecture on organoids near end of course.
Why to use animals in research?
- Basic science: molecular events regulating development and disease
- Veterinary sciences: lots of research done on animals not for humans but for helping them =>
vet
Prof. Tylzanowski
Themes/Questions
Biomedical research needs tools that would permit efficient disease study and exploration of curative
strategies. Not all problems can be addressed in an organism-free context. The class will explore
several animal proxies of humans and explore the advantages and limitations of these models. Some
alternatives to animals will be presented with the advantages and limitations as well (the last class).
- What is the best animal model to study humans?
- Am I really like a fruit fly?
- What are the scientific basis supporting use of animals in biomedical research?
Biomedicine: “We don’t cure patients, we cure diseases.”
Challenges and solutions in medicine today
- Challenge: molecular basis of disease processes.
- Solutions?
Developmental process at wrong place/time?
Cancer, metastasis, etc.
Short view on history of Developmental Biology
Descriptive studies of change: Take 20 eggs or more and give them to 2 or 3 hens to incubate, then
each day from the second onwards till the time of hatching take an egg, break it, and examine it (the
first account by Hippocrates).
See workshops!
Lots of progress got halted as Christianity being ever more dominant, grinding science to a halt.
- Performation theory: The organism is preformed as a complete miniature structure in the
egg and simply grows larger as it develops. People that support this idea were called ‘Ovists’.
- Theory of homunculus: suggested that a little human embryo (homunculus) was hidden in
the head of every sperm. People that support this idea were called ‘homunculists’ or
‘spermists’.
Leonarde Da Vinci: dissection of the human fetus and quantitative measurement of embryonic
growth. First to give evidence that embryos change in weight, size and shape over time.
Andreas Vesalius: first described the human placenta.
Marcello Malphigi: study structures such as lungs, kidneys, spleen, brain and skin. First microscopic
account of chick development. Concluded that egg contained miniature chick. Responsible for rise of
preformationist doctrine.
Recapitulation theory EXAM!
Also called biogenetic law, states that ontogeny repeats phylogeny. Means developmental stages of
higher animals closer resemble the adults of their ancestral species. Throughout development we re-
run things that have happened => evolution. => why we use animals in research.
,Experimental models
- Mathematical models computer simulations
- Non-living mechanical or molecular systems biochemistry
- Living systems composed of samples from the original animal tissue or organ culture
- Whole living animals human and non-human
o No research on humans but nature does it for us. Mutation gives different
phenotype.
, Rationale…
- Physiological relevance highest on right
- Experimental traceability highest on left
See separate lecture on organoids near end of course.
Why to use animals in research?
- Basic science: molecular events regulating development and disease
- Veterinary sciences: lots of research done on animals not for humans but for helping them =>
vet
