Left/Right Axis Specification (Mammals)

Question 1

Normal positioning left/right is known as :

Answer 1

Situs solitus

Question 2

What are three general signs of asymmetry in vertebrates during early development?

Answer 2

Rudimentary organs are offset, the heart forms on one side, and the lungs have differing number of lobes.

Question 3

Total inverse positioning left/right is known as:

Answer 3

Situs inversus totalis

Question 4

Heterotaxia:

Answer 4

Randomization of organ position

Question 5

Name for condition where the heart is abnormally on the ___ is called ___.

Answer 5

right, and dextrocardia.

Question 6

Relationship between lefty I, Nodal, and pitx2.

Answer 6

Lefty I works along the midline and inhibits nodal, which acts on the left to form pitx2, a transcription factor.

Question 7

What is Kartagener’s Triad?

Answer 7

A condition in which flagellum cannot move, due to loss of outer dynein arms. Also known as primary ciliary dyskinesia.

Question 8

How does Kartagener’s Triad prove the need of the nodal cilia in proper left/right axis specification?

Answer 8

About 50% of people with Kartagener’s Triad have situs inverses totalis.

Question 9

What does IFT stand for?

Answer 9

Intraflagellar transport

Question 10

What kinesis is required for iFT?

Answer 10

KIF3B

Question 11

Through nodal flow, what ion is located on the left side of the node?

Answer 11

Calcium

Question 12

In fish, nodal cilia are located___ that results from ___ cells

Answer 12

in Kupffer’s vesicle, dorsal forerunner