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Theses/Dissertations

2013

Cell and Developmental Biology

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Full-Text Articles in Life Sciences

A Novel Gain Of Function Of The Irx1 And Irx2 Genes Disrupts Axis Elongation In The Araucana Rumpless Chicken, Nowlan Freese Aug 2013

A Novel Gain Of Function Of The Irx1 And Irx2 Genes Disrupts Axis Elongation In The Araucana Rumpless Chicken, Nowlan Freese

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Caudal dysplasia describes a range of developmental disorders that affect normal development of the lumbar spinal column, sacrum and pelvis. An important goal of the congenital malformation field is to identify the genetic mechanisms leading to caudal deformities.
To identify the genetic cause(s) and subsequent molecular mechanisms I turned to an animal model, the rumpless Araucana chicken breed. Araucana fail to form vertebrae beyond the level of the hips. I performed a genome wide association study to identify candidate genomic regions associated with the rumpless phenotype, compared to tailed Araucana. A candidate region of chromosome 2 containing just two ...


Early Skeletal Morphogenesis: The Role Of Pharyngeal Endoderm Derived Signaling During Specification Of Craniofacial Skeleton And Interplay Of Mechanical Forces And Molecular Signaling During Skeletal Condensation, Poulomi Ray May 2013

Early Skeletal Morphogenesis: The Role Of Pharyngeal Endoderm Derived Signaling During Specification Of Craniofacial Skeleton And Interplay Of Mechanical Forces And Molecular Signaling During Skeletal Condensation, Poulomi Ray

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This study examines the fundamental principles governing the early
stages of skeletal morphogenesis. I specifically investigate the specification of mesenchymal progenitor cells to a skeletal fate. Using explant culture system, I determine that the pharyngeal endoderm was sufficient, but not necessary for specifying pre-chondrogenic identity. FGF signaling is both sufficient and required for specification of Sox9 expression and specification of prechondrogenic identity, as demonstrated by the addition of recombinant FGF protein or the FGF receptor inhibitor (SU5402) to explanted tissue, respectively. However, FGF signaling cannot maintain Sox9 expression or initiate the chondrogenic program as indicated by the absence of Col2a1 ...