Developmental Genetics Flashcards
3 ways main cellular development occurs
specification, determination and differentiation
Specification
is the first cues that confer spatial distinct identity, capable of differentiating autonomously (reversible)
determination
time-point when a specific developmental fate becomes fixed
Differentiation of a cell
process by which a cell achieves final form and function
meristem
a group of undifferentiated cells in a plant
What are the MADS-box genes
they are genes involved in controlling all major aspects of development organs , encode transcription factors in eukaryotic organisms
in floral homeotic transcription factor genes, what are the 3 classes?
A,B,& C
If class A is ONLY expressed, what will become of the cells
sepals
If A and B are expressed TOGETHER what will be expressed
the petals develop
If B and C are expressed together what is developed
stamens
if c class is ONLY expressed what will only develop
carpel
what happened if we remove expression of one of the class types of the gene?
The development of the removed expression will not be expressed on the flower
4 components of the flower outer to inner
sepal, petal, stamen, carpel
the two different sets of genes controlling embryonic development in Drosophila (fruit fly) and where they come form
maternal-effect gene- from mother
zygotic genes- made in zygote
maternal-effect genes expressed by the mother placing what in egg and what it does?
it places mRNA and protein products in egg.
it encodes proteins that regulate gene expression and forms the anterior/posterior group gradients
what is the transcriptional hierarchy development in order
formation of anterior/posterior group
zygotic genes then segregate into the gap, pair-rule and segment polarity genes. Finally homeotic gene segments are created and differentiation occurs
the two types of zygotic genes
segmentation genes and the homeotic selector
what do the segmentation genes do and what are the 3 classes
3: gap, pair-rule and segment polarities
they divide embryo into segments and defines the #, size and polarity of each segment
What is the homeotic selector
the are genes that specify the fate of each segment, they activate the genes to make a specific body part determine what segment becomes what
gap gene mutation
deleted “gaps” in the segmentation pattern
pair-rule mutations
every other segment deleted
segment polarity mutations
defects in one side of each segment
combination of maternal-effect and gap proteins control what
an individual pair rule stripe formation
once segment position information is established what is then expressed and what does it do?
the homeotic gene (HOX) is expressed this indicated what the segment will differentiate into
what do transcriptional networks do
they regulate development by generating patterns of gene expression
how do the transcriptional networks work?
they regulate development by generating patterns of gene expression
what is key in transcriptional networks
cis-regulatory elements
what activated the cascade of genes
transcription factors
what is the cascade factor
a factor at one level regulating many at the next
