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Title: Pattern Formation in Cockroach Leg Regeneration.
Author: French, V. K.
ISNI:       0000 0001 3484 3653
Awarding Body: University of Sussex
Current Institution: University of Sussex
Date of Award: 1973
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The problems of development and regulation of spatial pattern are considered in general terms, and specifically with respect to the insect segment. The cockroach, Blattella germanica, was used in a series of amputation and grafting experiments. Regeneration from the autotomy plane is illustrated and discussed, and intercalary regeneration was investigated by grafting between cuticle colour mutants. Regeneration from very proximal levels of the leg is shown to proceed proximo-distally. It is demonstrated that the coxa, femur or tibia, when implanted into the abdomen, can regenerate from the distal end. When grafted to the antennal position, the coxa retained its ability to regenerate leg segments. With graft tarsus removed, congruent grafts between tibias or between non-homologous segments often resulted in regeneration from both surfaces of the junction. The regenerates could fuse at homologous levels to form a single (often distally incomplete) structure. When the graft tarsus was not removed, the junction just healed. Grafts made with reversal of one transverse axis resulted in the formation of two complete regenerates, one organised from each of the levels of the junction. Fusion gave a double structure. When the tarsus was removed, regeneration could occur from a lateral wound made in the tibia of a fully formed leg, or in the tibia or femur of a developing regenerate. It is concluded that segment type can only change when: i) confrontation occurs between opposite faces of the leg. Regeneration always occurs and is complete. ii) cellular contact is disrupted and the terminal tarsus is removed, Regeneration sometimes occurs and is usually incomplete. Cockroach and Drosophila leg regeneration is compared. Various models are applied to insect leg regeneration and found to be unsatisfactory.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available