Hox Genes & Segmentation Flashcards
Which gene, if mutated, can transform the third thoracic segment to the second thoracic segment in Drosophila?
Ultrabithorax (Ubx)
Ultrabithorax gene
Recessive mutation –> transformation of third thoracic segment to the second thoracic segment
What is homeotic transformation?
One structure replaced by another
Mutations in Ubx do not alter….
The number of segments
What is the haltere?
The balancing organ of a two-winged fly
What does Ubx act as?
Control/Selector gene to specify haltere identity
What does it mean if a gene has an autonomous function?
Mutation in this gene affects the cells in which its present
What does it mean if a gene has a non-autonomous function?
Affects other cells
Ubx directs cells down which pathway?
Metathoracic pathway
Why do cells in different segments interpret positional information differently?
Due to the activity of selector genes
What is the Bithorax complex (BX-C) composed of?
3 transcription units
- Ubx
- AbdA
- AbdB
What does the arrangement of the genes that are part of the BX-C reflect?
The order in which they function along the anterior-posterior axis of the embryo
What does each gene in the BX-C contain?
Homeobox genes
Are BX-C genes required for segmentation?
No
What does the BX-C do?
Control the differentiation of the abdominal and posterior thoracic segments
What is the name of the complex that control the differentiation of the abdominal and posterior thoracic segments?
Bithorax complex (BX-C)
Which complex is expressed in T2 segment?
Antennapedia complex (ANT-C)
What does the Antennapedia complex (ANT-C) do?
Contains homeobox genes that control development of head and thoracic segments
The development of the head and thoracic segment is controlled by?
The Antennapedia complex (ANT-C)
What do dominant mutations of the Antennapedia gene cause?
Transformation of the antenna to the leg (head to thoracic segment)
What is a transformation of the antenna to the leg caused by?
Dominant mutation in the Antennapedia gene
Hox genes are higgled conserved in vertebrates through evolution
- Could lead to homeotic transformations
- Expressed in spatially restricted patterns
- Mutations in HOXD13 causes synpolydactyly
