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Identifier 000460506
Title Molecular and cellular basis of biramous and uniramous limb formation
Alternative Title Μοριακή και κυτταρική βάση του σχηματισμού δισχιδών και μονοσχιδών άκρων
Author Ραφαηλίδου, Κυριακή Νιόβη Ν.
Thesis advisor Παυλόπουλος, Αναστάσιος
Reviewer Δελιδάκης, Χρήστος
Μόσχου, Παναγιώτης
Abstract Animal limbs exhibit a tremendous diversity in terms of their morphology and by extent their funcCon. The origin and diversificaCon of limbs enabled animals to adapt to a vast spectrum of ecological niches. Limbs are secondary developmental fields that develop along their proximal-distal axis perpendicular to the primary anterior-posterior and dorsal-ventral body axes. All limb types observed in extant arthropods are believed to have originated from ancestral biramous (Y-shaped) limbs composed of a proximal part (protopod) bearing an inner, ventral branch (endopod) and an outer, dorsal branch (exopod). Biramous limbs are sCll widespread in extant crustaceans, but have been lost in terrestrial arthropod lineages, such as insects, that develop uniramous (I-shaped) limbs composed of the protopod and a single distal branch (telopod). Our knowledge on arthropod limb development comes almost exclusively from studies of uniramous limbs in the insect model Drosophila melanogaster and we have no clue how developmental paUerning mechanisms shape biramous limbs. The crustacean Parhyale hawaiensis is an emerging model organism that develops 8 pairs of uniramous limbs in the thorax and 6 pairs of biramous limbs in the abdomen serving as an ideal candidate to address this limitaCon. In this Master Thesis, I compared the developmental mechanisms of uniramous and biramous limb formaCon in wild-type Parhyale embryos. To achieve that, I analysed in uniramous and biramous Parhyale limbs the dynamic expression paUern of three important genes paUerning the limb proximal-distal axis (known as leg gap genes): Distal-less, dachshund and homothorax. This Cmecourse expression analysis was performed using the next-generaCon HybridizaCon Chain ReacCon v3.0 protocol for RNA fluorescence in situ hybridizaCon combining sensiCvity, mulCplexing, cellular resoluCon and quanCtaCon of mRNA levels in the context of whole-mount embryos. Careful analyses of gene expression dynamics revealed very similar paUerns between uniramous and biramous limbs during the early specificaCon and outgrowth of a single proximal-distal axis. However, during later stages, the proximal-distal axis remained undivided in uniramous limbs but split in biramous limbs, providing support for the hypothesis that uniramous limbs in crustaceans are not the product of a ramus loss (exopod loss), but the product of the suppression of the proximal-distal axis subdivision that occurs in biramous limbs. In addiCon, comparison of the relaCve expression paUerns of these leg gap genes generated hypotheses about their possible cross-regulatory interacCons that specify their proximal-distal domains and final limb morphologies. Overall, these findings provide valuable insights into the interplay between molecular geneCcs and cellular processes that produce arthropod limbs with diverse shapes that will be funcConally tested in the future.
Language English
Subject Arthropods
Biramous limbs
Crustaceans
Develpment
Gene expression
HCR based RNA-Fish
Leg Pd axis patterning genes
Morfogenesis
Parhyale hawaiensis
Uniramous limbs
Ανάπτυξη
Γονίδια καθορισμού εγγύς-άπω άξονα
Γονιδιακή έκφραση
Δισχιδή άκρα
Καρκεινοειδή
Μονοσχιδή άκρα
Μορφογένεση
Issue date 2023-11-24
Collection   School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/a/c/9/metadata-dlib-1700651925-523600-11335.tkl Bookmark and Share
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