Devo Lect 22 - Control of Devo. Flashcards Preview

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Flashcards in Devo Lect 22 - Control of Devo. Deck (11)
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2

Body plan setup

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

3

Homeotic mutants

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

4

Homeotic genes

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

5

Homeobox

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

6

Homeodomain

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

7

Hox genes in mouse

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

8

Hox genes in all organisms

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

9

Hox knockouts in mouse

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

10

Evolutionary changes by hox genes in insects

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

11

Genes in limb development in drosophila***

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

12

Compare sequence of Ubx gene

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