INTRODUCTION TO DEVELOPMENTAL BIOLOGY Flashcards
the study of the process by which organs grow and develop
synonymous with ontogeny
Developmental Biology
CONCERNS OF DEVELOPMENTAL BIOLOGY
- Changes with time on life scale
- Ontogenetic development
- Embryogenesis - Changes in form and function
- “Morphogenesis”
- Biochemistry - Integrative and Eclectic (wide-ranging)
WHY IS DEVELOPMENTAL BIOLOGY IMPORTANT?
- Can help in sustaining food resources (SDG 1 & 2) = improve crop and plant cultivation
- Developmental defects in humans are very abundant (SDG 3) = address major population health challenges.
- Developmental Biology is a generator of new ideas and concepts (by asking fundamental questions)= underpins modern biomed sciences
- Reaches across the different levels of biological complexity and explanation = tracing back to events at the level of genes & cells (Organismal -> Cellular)
- Makes strategic use of suitable animal models
Specific questions scrutinized by developmental biologists
- Differentiation (ex. Pax6 gene - Pancreas, lens and cornea, neural tube, retina)
- Pattern formation (ex. Zebrafish - gradient, induction)
- Morphogenesis (ex. Frog - provide spatial information)
- Growth (Teratogens)
- Reproduction
- Environmental Integration
- Regeneration
- Evolution
- Human Development
The ultimate stem cell
Zygote - a fertilized egg
A historical approach to embryology that uses experimental methods to study the development of embryos
Classical embryology
process by which the presence of one tissue influences the development of others
Induction
How do our cells know when to stop dividing?
when they receive chemical signals from other cells, or when their telomeres shorten to a critical length
How come our arms are are
generally the same size on both
sides of the body?
Hox genes
How is cell division so tightly
regulated?
Cyclins and CDKs
Cell checkpoints
Chemicals that disrupt normal development
Teratogens
Why some organisms can
regenerate every part of their
bodies?
Stem cells
the study of how environmental factors and behaviors can change gene activity without altering DNA sequences
Epigenetics
one of the first to allude to the
concept of preformationism
Hippocrates
a theory that organisms develop from miniature versions of themselves
Embryonic structures are preformed within the gamete
(either egg or sperm)
preformation
Credited with 1st notions on embryology
“On the generation of animals”
Studied embryos of different organisms
Aristotle
embryonic structures arise anew from the interaction of substances within the gametes
Epigenesis
Visualized epigenesis of embryonic germ layers
studied the chick embryo
Christian Pander
father of Modern Embryology
described notochord, discovered mammalian egg, proposed 4 laws of development
Karl Ernst von Baer
________ gene is an important tillering/branching-related transcription factor gene that regulates tillering by integrating environmental and developmental cues
teosinte branched 1 (tb1)/CYC
2 major accomplishments in development
- Differentiation - unicellularity to multicellularity
- Ensuring continuity of life
a birth defect that causes the complete absence of one or more limbs
Amelia
- The more general characters of a large group appear earlier in the embryo than the more special characters.
- From the most general forms, the less general forms are developed, and so on, until finally, the most special forms arise.
- Every embryo of a given animal form, instead of passing through the other forms, rather becomes separated from them.
- Fundamentally, therefore, the embryo of a higher form never resembles any other form, but only its embryo.
Baer’s Laws
Experimental Approaches
Defect experiments
Isolation experiments
Recombination experiments
Transplantation experiments
