BIOL V04 Lecture: Developmental Genetics (Ch 17)
© 2012 copyright Marta D. de Jesus
I. Animals are complex systems
A. preformation
B. epigenesis
C. modern
D. model organisms
http://www.hhmi.org/genesweshare/g200.html
II. What is the overall sequence for animal development?
egg & sperm -> zygote ->embryo-->morula-->blastula -->gastrula--------> larva --------> adult
III. How do the cells know what to do?
A. 2 sets of conditions set up development
1. eggs
2. as the embryonic cells
B. How were these studied?
1. early investigators
a. fate maps
1) eg; amphibian
For more:http://scienceblogs.com/pharyngula/2006/07/ancient_rules_for_bilaterian_d.php
2) eg: C. elegans
mosaic develeopment
b. Drosophila development & imaginal disks
c. rare mutants
C. processes of development
1. growth
2. cell division
3. apoptosis
4. determination
nuclear equivalence
b. differential gene expression
5. differentiation
tissue-specific proteins
c. totipotent
1) in plants, Steward (1950s)
clone
2) frog experiments
Briggs & King (1950s)
Gurdon (1960s)
3) mammals
Dolly {Wilmut & Campbell (1996)}
4) animal stem cells
(i) zygotes
(ii) embryonic stem cells (ES)
(iii) adult stem cells
2007 induced pluripotent cells (iPS)
http://learn.genetics.utah.edu/content/tech/stemcells/
some successful treatments: http://learn.genetics.utah.edu/content/tech/stemcells/sctoday/
6. pattern formation
morphogen
a. probably best described in Drosophila
1) maternal-effect genes
eg: egg-polarity genes
2) zygotic segmentation genes
(i) gap genes
(ii) pair-rule genes
(iii) segment-polarity genes
3) homeotic genes
(ii) homeobox
(iii) homeodomain
(iv) sequence of homeotic genes
http://www.hhmi.org/genesweshare/b120.html
one example of how sets of these matter: http://blogs.scientificamerican.com/thoughtomics/2012/03/14/thanksto-extra-genes-eels-transform-from-ribbons-to-tubes/
b. in mammals
1) chimeric mouse
2) transgenic mouse
c. in plants
ABC model of flowering
SEPALLATA genes
IV. Exceptions to nuclear equivalence
A.
B. gene rearrangement in trypanosomes
C. generation of immune system diversity
V. Cancer
dedifferentiate
B. tumor
1. benign
2. malignant
dysplasia
metastasis
C. What causes cancer? carcinogenesis
1. always
2. oncogene
a. proto-oncogenes = cellular oncogenes
eg: erb-B2 = HER-2 = neu
3. tumor supressor genes
2 hit hypothesis
b. examples
1) RB
2) p53
D. other genes
1. DNA repair genes
2. eg: angiogenesis genes
3. eg: telomerase
E. Is this a stem cell problem?
cancer stem cells (CSCs)
http://stemcells.nih.gov/info/2006report/2006chapter9.htm
E. contributing to the problem
F. complex, multi-stage process
Colon cancer
start of A Young Woman and a Billion Flies: http://www.hhmi.org/genesweshare/b200.html