Post-graduate theses
Current Record: 23 of 802
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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
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Ραφαηλίδου, Κυριακή Νιόβη Ν.
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Thesis advisor
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Παυλόπουλος, Αναστάσιος
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Reviewer
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Δελιδάκης, Χρήστος
Μόσχου, Παναγιώτης
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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.
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Language |
English |
Subject |
Arthropods |
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Biramous limbs |
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Crustaceans |
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Develpment |
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Gene expression |
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HCR based RNA-Fish |
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Leg Pd axis patterning genes |
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Morfogenesis |
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Parhyale hawaiensis |
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Uniramous limbs |
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Ανάπτυξη |
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Γονίδια καθορισμού εγγύς-άπω άξονα |
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Γονιδιακή έκφραση |
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Δισχιδή άκρα |
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Καρκεινοειδή |
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Μονοσχιδή άκρα |
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Μορφογένεση |
Issue date |
2023-11-24 |
Collection
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School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/a/c/9/metadata-dlib-1700651925-523600-11335.tkl
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Views |
1000 |
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