Developmental Biology Flashcards
why is drosphilia important?
key model organism
rapid life cycle
small size
genetically tractable
what is homeosis?
changing of one body part so it resembles another
what is polarity?
regional difference in a state of commitment
what is axis?
rotation is of some pratical significance
what is potency?
total of things into which tissue can develop
why do we need model systems?
easy to manipulate quantity short gen times genomes can allow in vivo visualisation
vertebrate and invertebrate model systems?
invertebrates - drosophila, c.elegans, sea urchin, sea squirt
vertebrate - chick, zebra fish, mouse, african clawed frog
what is good about plant model organisms?
easy and inexpensive, genetic and imaging tools, mutants
arabidopsis - mustard family
what makes a suitable model organism?
rapid life cycle
small size
genetically tractable
accessible embryos
what is special about drosophila?
morphogen gradients, positional info, developmental fields, boundaries
what are morphogens?
signal molecules that can affect behaviour of a cell
what is a bicoid?
first example of a morphogen, found in drosophila
how does bicoid mRNA work?
localised to anterior pole, translated into protien spreading to posterior forming an anterior-posterior gradient
how does bcd work?
changes the levels of morphogen protein gradient shifting the position of where the target genes are activated
what happens with drosophilia segmentation?
morphogen gradient activates or represses various downstream genes depending on different thresholds for response
what does hox gene code determine?
differentiation pathways
what is the embryonic field?
the area of embryo tissue within which a certain process occurs
what are compartments?
region within which progeny of every cell remains confined - needs boundaries either physical or determination
what is xenopus laevis
african clawed frog
what is cleavage?
cell division without growth
what is induction?
process by which one embryonic region interacts with a second region to influence the second regions differentiation or behaviour
how do competent tissues become differentially determined?
in response to conc of chemical signals from another region of the embryo
how is the secondary axis formed?
new notochord arises from host donor tissue
new neural tube and somite formed by host and donor tissue
what is fate?
the final stage of development
how do we map fate?
vital dyes - inflorscence
fluoresenclty tagged proteins
transplantation of pigmented into albino tissue
what is determination?
progressive restriction in developmental protential of different cell types
irreversible
if graft appears how do we know if its determined?
- old position - determined
new position - undetermined
what is specification?
isolating cells and they still become what they should
what is competence?
cells able to recieve signals for only a short time
what is special about c.elegan?
illustrates development via cell lineage
easy to observe
can name each cell all the way through
what is lineage?
embryos with invarient cleavage patterns such that a family tree can be drawn
state of commitment inherited from determined parent cell
what is mosaicism?
map of specified regions matches fate map
what is regulation?
specification of isolated parts doesn’t correspond to the fate map
also
reestablishment of the fate map on a domain of uncomitted tissue
what are p granules?
in p cell lineage that become germ lines
what happens when ced-3 joins?
apoptosis and its a cell death defective caspase
what does vulva development show?
signalling
what is laser ablations?
when cells could become the vulva but only some do
features of mosaic development?
determinate
separation of blastopore results in incomplete parts of embryos
features of regulation development?
undetermined
remaining cells can compensate for tissue loss
what is the pathway a cell takes as it becomes specialised?
undifferentiated - specified - determined - differentiated
