2I- Developmental Genetics

Question 1

Why is using animals good for understanding human genetics?

Answer 1

developmental gene lineages and major elements (genes and pathways) are pretty much the same for organisms as different as flies and humans

Question 2

What are paracrine signal molecules?

Answer 2

proteins that diffuse across a small distance to induce a response in neighboring cells.

Question 3

What is the role of the paracrine molecule Fibroblast growth factor?

Answer 3

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

Question 4

What is the role of the paracrine molecules hedgehog family?

Answer 4

important in designating axis of the body, motor neuron in the neural plate, and patterning of limbs

Question 5

What is the role of the paracrine molecules wingless (Wnt) family?

Answer 5

determines polarity of limb formation, and axis

Question 6

What is the role of the paracrine molecule TGF β?

Answer 6

big family of homodimers/heterodimers, and includes BMP (family that induces bone formation)

Question 7

What are DNA transcription factors?

Answer 7

genes encoding proteins that turn on or off other genes, can regulate many different genes, and these genes can regulate others

Question 8

What are extracellular matrix proteins?

Answer 8

macromolecules responsible for the architecture or scaffolding of the tissues and organs

Question 9

Why can a mutation in a transcription factor produce pleiotropic effects?

Answer 9

transcription factors can regulate genes that further regulate other genes (cascade effect), leading to pleiotropic effects

Question 10

Osteogenesis imperfecta has a defect in which extracellular matrix protein?

Answer 10

Collagen (type I)

Question 11

What are the symptoms of osteogenesis imperfecta?

Answer 11

bones are easily fractured due to collagen losing its strength from impoper folding and formation

Question 12

Marfan’s syndrome has a defect in which extracellular matrix protein?

Answer 12

Fibrillin

Question 13

What are the symptoms of Marfans syndrome?

Answer 13

long limbs, arachnodactyly, aortic dissection

Question 14

Williams syndrome has a defect in which extracellular matrix protein?

Answer 14

Elastin

Question 15

What are the symptoms of Williams syndrome?

Answer 15

supravascular aortic stenosis

Question 16

Junctional Epidermolysis bullosa has a defect in which extracellular matrix protein?

Answer 16

Laminin

Question 17

What are the symptoms of Junctional Epidermolysis bullosa?

Answer 17

large blisters form anytime they want to

Question 18

Achondroplasia has a defect in which receptors?

Answer 18

FGF receptors

Question 19

What are the symptoms of achondroplasia?

Answer 19

Dwarfism, limbs a lot shorter than the trunk, craniosynostosis, and nubs for hands

Question 20

What causes Hirshprung’s disease?

Answer 20

when the bowel does not move as much as it should, due to failure of neural crest cells to migrate to their intended regions

Question 21

What causes Holoprosencephaly?

Answer 21

failure of midline development, so basically the brain doesn’t make two hemispheres

Question 22

What causes situs inversus?

Answer 22

left/right reversal of organ position due to the transcription factor mutation of ZIC3

Question 23

What causes Holt-Oram syndrome?

Answer 23

TBX5 mutation causes mutations of the upper limb, can result in no thumbs, or absent radial bone

Question 24

What part of the mesoderm do FGF molecules stimulate?

Answer 24

Progress Zone (PZ)

Question 25

What is the role of SHH in development?

Answer 25

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.

Question 26

What are knockout mice?

Answer 26

It’s where scientists have knocked out specific sequences and studying the resulting phenotypes

Question 27

What are conditional knockouts in mice?

Answer 27

are for specific regions or specific cell lines for knockouts that would typically be lethal it were applied to all the cells.

Question 28

What are the main roles of the HOX genes?

Answer 28

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

Question 29

What is a homeobox?

Answer 29

a DNA sequence found within genes that are involved in the regulation of patterns of anatomical development

Question 30

What is “paralog” in reference to homeoboxes?

Answer 30

equivalent genes in a homeocomplex, these genes may be very similar to one another and can sometimes take on each other’s roles

Question 31

What is homeotic transformation?

Answer 31

transformation of a structure to a different structure due to changes in expression

Question 32

What is a homeodomain?

Answer 32

genes that code for transcription factors, specifically the DNA binding region.

Question 33

What is Temporal colinearity?

Answer 33

Expression of genes are controlled by time

Question 34

What is Spatial colinearity?

Answer 34

expression of genes controlled by location

Question 35

IPF1 stimulates the transcription factor of what molecule in the pancreas?

Answer 35

insulin

Question 36

IPF1 allows the growth of what organ?

Answer 36

pancreas