Lecture 9: Developmental Genetics I

Question 1

Homeobox

Answer 1

contain highly conserved sequence of 180 nucleotides coding for a 60 amino acid homeodomain

Question 2

In which direction are homeobox containing genes activated?

Answer 2

3’ to 5’ direction (opposite of transcription)

Question 3

What is the result of a loss-of-function mutation in homeobox genes?

Answer 3

Posterior to anterior transformations

Question 4

What is the result of a gain-of-function mutation in homeobox genes?

Answer 4

Anterior to posterior transformations

Question 5

T-box genes (Tbx)

Answer 5

Contain conserved T-box coding 180-200 amino acids; plays role in inducing mesodermal germ layer and coordinating limb development

Question 6

Helix-loop-helix genes

Answer 6

Code for basic helix-hoop-helix transcription factors; involved in homo/heterodimerization, important in myogenesis

Question 7

Forkhead (Fox) genes

Answer 7

Type of helix-loop-helix family expressed in many developing organs throughout the body

Question 8

Zinc finger transcription factors

Answer 8

Contain zinc ions bound to polypeptide chain causing chain to form finger-like projections inserted into DNA helix. Gene families = Sox, WT1

Question 9

Sox genes

Answer 9

High-mobility group domain binding to minor groove on DNA helix, including SRY gene

Question 10

WT1 gene

Answer 10

Important for development of embryonic kidney and adult kidney