Devo Lect 22 - Control of Devo.

Question 2

Body plan setup

Answer 2

For any animal, it is controlled by the same set of genes

Question 3

Homeotic mutants

Answer 3

Found in fruit fly - Parts similar to other body parts produced (ie two thoraxes with two set of wings, etc) - caused by mutations in homeotic genes

Question 4

Homeotic genes

Answer 4

Each form a different body part; all found on the same chromosome; expressed in chromosomal order, never seen before

Question 5

Homeobox

Answer 5

180bp sequence, common to all homeotic genes; makes the homeodomain

Question 6

Homeodomain

Answer 6

60 aa made by homeobox; a transcription factor (helix-loop-helix)

Question 7

Hox genes in mouse

Answer 7

same genes, but 4 sets (a, b, c, d). Still anterior to posterior;

Question 8

Hox genes in all organisms

Answer 8

Only one cluster in most animals, vertebrates have multiple sets; some similar genes in plants and even a few in bacteria

Question 9

Hox knockouts in mouse

Answer 9

Hoxa-1 -/- = abnormal segmentation of hindbrain; Hox-10 -/- = extra ribs on lumbar vertebrae –> evolution of snakes, fish

Question 10

Evolutionary changes by hox genes in insects

Answer 10

Aysheaia (ancestor to insects); some key differences - not segmented, many legs, no wings

Question 11

Genes in limb development in drosophila***

Answer 11

Antp (antenopedia), Ubx (ultrabithorax), AbdA (abdominal); RNAi experiment of Ubx and AbdA ressembles Ayshaeia

Question 12

Compare sequence of Ubx gene

Answer 12

Polyalanine region of protein only present in insects, other arthropods lack that region; represses forming too many legs