Insect Ooogenesis- L14 Flashcards
What are kernels?
GRNs for a given development function not used elsewhere in development.
What does GRN stand for?
Gene Regulatory Network
GRNS have what type of wiring?
Recursive Wiring
What does recursive wiring mean?
Products of many genes are required for the function of the kernel.
What would happen if there was interference with expression of anyone one kernel gene?
This would destroy the function of the entire kernel and have severe developmental consequences
What does oogenesis mean
egg formation
How does the oocyte split?
Through meiosis to form a haploid cell, the ovum.
What is a feature of a mature ovum?
Yolk containing vitellin
Vitellogenesis may occur through what?
A lengthened prophase of meiosis
What happens during vitellogenesis?
The process of yolk formation via nutrients being deposited in the oocyte
Ooogenesis can be categorised by the relationship of the oocyte to what cells?
solitary, follicular, nutrimentary
By what pathway can oogenesis be catgeorised?
The synthetic pathway for the stored yolk in the cytpolasm
- autosynthetic oogenesis
- heterosynthetic oogenesis
What cells are missing in solitary oogenesis?
Follicle and nurse cells
What is different about follicular oogenesis?
oocytes are associated with a covering of somatic cells
EXAMPLE: In the tunicate ascidella aspersa
What type of ovaries do locusts have?
Panoistic ovaries (with follicle cells) that develop within ovarioles.
What cells are oocytes associated with in nutrimentary oogenesis?
Nurse cells (sister cells)
What type of development do drosophillia ovary show?
polytropic meroistic development, in which oogonia divide into oocyte and nurse cells
What is autosynthesis?
The synthesis of yolk and other stored materials by the oocyte itself.
What is heterosynthesis?
The synthesis of yolk proteins by other, non-germ cells, characterised by the uptake of vitellogenin (later stored as vitellin)
Who created the idea of regional organisation?
Nusslein-volhard and Wieschaus.
What was the procedure for regional organisation experiment?
Treated flies with chemical mutagen and classified lethal/near lethal mutants dependent on effects on bristle patterns and segmental organisation.
What were the findings of the regional organisation experiment?
Lead to term MATERNAL EFFECT GENES.
Larvae often appeared to have missing segments. Some mutations were dependent on genotype of mother - maternal factors are deposited in oocyte. Such gened termed MATERNAL EFFECT GENES, expressed in ovarian tissues during oogenesis.
