Summary
Summary part 2 Evolutionary Developmental Biology
- Course
- Institution
I passed this course with a 7
[Show more]
1 review
By: edaselinkaya • 9 months ago
Seller
Follow
lvd26
Reviews received
Content preview
Summary Part 2 Evolutionary Developmental BiologyLecture 15-17 – EvoDevo
EvoDevo→ Compare developmental processes to infer ancestral relationships and
understand how developmental processes evolved
Why look at development?
Because the body plan is established during development!
A single cell (zygote) contains all information on the adult body plan
Body plans enroll step by step
• Signaling gradients, axis formation
• Cell differentiation & fate determination
• Proliferation, apoptosis, cell migration
• Modularity, segmentation
• Organogenesis
• Maturation, timing (heterochrony), neoteny
Founding fathers of EvoDevo
- Ernst Haeckel, 1866
- Biogenetic law
• “Ontogeny recapitulates phylogeny”
- Karl Ernst von Baer, 1828
• “The embryo successively adds the organs
that characterize the animal classes in the
ascending scale.”
Not entirely... but similarities in embryonic stages
reflect evolutionary conservation of embryonic development
Hourglass model for morphological diversity
,The genetic toolbox for development is evolutionary extremely conserved
• How is this conservation reflected in developmental processes?
• How does this conserved toolbox allow the large diversity in body plans?
Evolution of additional transcription factors and signaling pathway genes
Gene expression patterns & signaling cascades are critical to differentiate developmental
processes: when, where, how much.
,Tissue patterning & body axes
Direction essential to coordinate organs and
tissues!
How are the body axes initiated?
• Anterior & posterior (A-P) = front & rear
• Dorsal & ventral (D-V) = back & belly side
• Left & right (Bilateria)
Drosophila: model for axis formation
Drosophila? YES!
• Many basal embryonic features pre-date the split
between Protostomes and Deuterostomes
• The developmental molecular toolbox also pre-dates
the split
• Homologous genes between Drosophila and
mammals
• Nobel prize 1995, genetic control of embryonic
development in Drosophila
The egg chamber of the Drosophila ovariole
- Developing eggs are provisioned with maternal mRNA during oogenesis
- Zygotes typically do not commence
transcription until after 2-3 divisions
- Drosophila egg has already a dorsal-
ventral axis induced by its mother!
Bicoid (Bcd) forms an A-P gradient
Bicoid is essential for establishing the A-P axis
Bicoid is the morphogen for head and thorax
development
Morphogen: compound with a non-uniform
distribution establishing positions of specialized
cell types and tissues
, Transplantation of Bicoid-containing cells induces ectopic anterior identity
• Anterior and posterior become thorax, the head is formed in the middle
• Ectopic: away from the normal position
Morphogens induce a signaling cascade that controls pattern formation
• Bicoid suppresses Caudal in the anterior part
• Nanos suppresses Hunchback in the posterior part
Dorso-ventral axis:
activation of Dorsal by the Toll-Spätzle pathway
Spätzle is the morphogen for dorso-ventral axis
formation
Phosphorylation of Dorsal at the ventral region
prompts translocation to the nucleus
Dorsal binds to DNA and regulates transcription of
target genes in a concentration-dependent manner
•Decapentaplegic (DPP)
•Sog
•Snail
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller lvd26. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.57. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
82871 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now