Lecture 12 Flashcards
1
Q
Determination
A
The process that leds up to a observational cell differentiation
2
Q
Differented cells?
A
… express different sets of genes
3
Q
How is the differentiated state achieved?
A
Transcription regulation, gene cascades
4
Q
Muscle cell determination and differentiation
A
- Muscle cells develop from embryonic precusor cells
- Other cell signals activate myoD master regulatory gene encoding the myoD transcription factor
- Cell determination has now occured and the cells are called Myoblasts
- myoD acitivates the expression of other muscle-specific transcription factors
- These in turn activiate genes for muscle proteins and block cell division
5
Q
Three main stages of Drosophilia Development
A
- Establising the main axes
- Establishing segments
- Filling in details
6
Q
The biocoid mutant
A
No anterior, two posterior ends
7
Q
Bicoid gene
A
- Example of a egg polarity gene which encodes proteins or mRNAs that the egg while in ovary
- If maternal gene is faulty, eggs fail to develop normally due to mutated transcription factors
8
Q
Gene cascade of segmentation genes
A
- Egg polarity genes
- Gap-genes - subdivide embryo into broad areas
- Pair rule genes - establish pairs of segments
- Segment polarity genes - establish anterior-posterior axis of each segment and induce homeotic genes
9
Q
Gap gene mutations
A
Produce a phenotype where part of the embryo is missing
10
Q
Homeotic mutants
A
Can cause the repeating of segments
11
Q
Homeotic genes and mutations
A
- First identified as a dominant mutation that changed the identity of body parts
12
Q
Hox genes
A
- Homeotic genes
- Determine the identity of embryonic regions along the anterior to posterior axis
- Hox genes encode transcription factors with a conserved DNA binding domain
- Hox genes occur in clusters, arranged in the same order as the regions they affect
- Similarity between flies and mammals, can be swapped
- Played huge part in evolution
