Flashcards in 2I- Developmental Genetics Deck (36)
Why is using animals good for understanding human genetics?
developmental gene lineages and major elements (genes and pathways) are pretty much the same for organisms as different as flies and humans
What are paracrine signal molecules?
proteins that diffuse across a small distance to induce a response in neighboring cells.
What is the role of the paracrine molecule Fibroblast growth factor?
responsible for cell migration, growth, and differentiation. The receptors for these are really important in bone development, and gene mutations often present with skeletal problems
What is the role of the paracrine molecules hedgehog family?
important in designating axis of the body, motor neuron in the neural plate, and patterning of limbs
What is the role of the paracrine molecules wingless (Wnt) family?
determines polarity of limb formation, and axis
What is the role of the paracrine molecule TGF β?
big family of homodimers/heterodimers, and includes BMP (family that induces bone formation)
What are DNA transcription factors?
genes encoding proteins that turn on or off other genes, can regulate many different genes, and these genes can regulate others
What are extracellular matrix proteins?
macromolecules responsible for the architecture or scaffolding of the tissues and organs
Why can a mutation in a transcription factor produce pleiotropic effects?
transcription factors can regulate genes that further regulate other genes (cascade effect), leading to pleiotropic effects
Osteogenesis imperfecta has a defect in which extracellular matrix protein?
Collagen (type I)
What are the symptoms of osteogenesis imperfecta?
bones are easily fractured due to collagen losing its strength from impoper folding and formation
Marfan's syndrome has a defect in which extracellular matrix protein?
What are the symptoms of Marfans syndrome?
long limbs, arachnodactyly, aortic dissection
Williams syndrome has a defect in which extracellular matrix protein?
What are the symptoms of Williams syndrome?
supravascular aortic stenosis
Junctional Epidermolysis bullosa has a defect in which extracellular matrix protein?
What are the symptoms of Junctional Epidermolysis bullosa?
large blisters form anytime they want to
Achondroplasia has a defect in which receptors?
What are the symptoms of achondroplasia?
Dwarfism, limbs a lot shorter than the trunk, craniosynostosis, and nubs for hands
What causes Hirshprung's disease?
when the bowel does not move as much as it should, due to failure of neural crest cells to migrate to their intended regions
What causes Holoprosencephaly?
failure of midline development, so basically the brain doesn’t make two hemispheres
What causes situs inversus?
left/right reversal of organ position due to the transcription factor mutation of ZIC3
What causes Holt-Oram syndrome?
TBX5 mutation causes mutations of the upper limb, can result in no thumbs, or absent radial bone
What part of the mesoderm do FGF molecules stimulate?
Progress Zone (PZ)
What is the role of SHH in development?
Shh is responsible for the signaling of the Zone of polarizing Activity. Shh is a very important transcription factor for dorsal/ventral patterns of the CNS and left/right axis.
What are knockout mice?
It's where scientists have knocked out specific sequences and studying the resulting phenotypes
What are conditional knockouts in mice?
are for specific regions or specific cell lines for knockouts that would typically be lethal it were applied to all the cells.
What are the main roles of the HOX genes?
HOX genes are basically the genes that control the sequence and location of segments of the body from head to tail. Primarily the anterior/posterior axis is determined by the combination of Hox genes
What is a homeobox?
a DNA sequence found within genes that are involved in the regulation of patterns of anatomical development