dev gen 2

Question 1

what if there is no mutant phenotype in recessive complementation test?

Answer 1

m1 and m2 complement each other (likely to be found on different genes)

Question 2

what is mutant phenotyp in 25% of progeny?

Answer 2

m1 and m2 do not complement each other - on same gene

Question 3

what is allelic series?

Answer 3

different mutant alleles of same genes

Question 4

what do kit and steel mutants show?

Answer 4

similar phenotype (same molecular pathway) -pigmentation changes, anaemia and infertility

Question 5

what do kit and steel form?

Answer 5

ligand receptor pair

Question 6

what do kit and steel code for?

Answer 6

steel codes for ligand (steel factor). kit codes for receptor for steel facotr

Question 7

what are kit and steel expressed by?

Answer 7

kit-melanoblast

steel - fibroblast

Question 8

what is required for melanoblast to develop into a melanocyte?

Answer 8

activation of kit receptor by steel factor

Question 9

what are functional kit and steel required for?

Answer 9

development of germ cells , melanocytes/melaoblasts and haemopoitic stem cells

Question 10

what is human condition caused b kit+steel mutants?

Answer 10

piebaldism

Question 11

what do epistasis experiments show?

Answer 11

order of gene action in a pathway

Question 12

what is expected ratio of phenotypic classes in 2 animals heterozygous for 2 mutations

Answer 12

9.3.3.1

Question 13

what is phenotype if mutations were in ame pathway?

Answer 13

9.3.4

(a/a;b/b) have same phenotype and b/b alone

Question 14

what is drosophila HH pathway required for?

Answer 14

segment poarity in embryo

Question 15

what are mutations in segment class?

Answer 15

hh, ptc, smo, wg

Question 16

what are 2 classes of segment polarity mutant phenotypes?

Answer 16

hedghog like - (hh,smo,wg) - lawn of denticles (loss of naked cuticle)

patched like (pc) -excess naked cuticle (loss of denticles)

Question 17

what was found in epistasis experiments in HH?

Answer 17

ptc is epistatic to HH
smo is epstatic to ptc

Hh—I Ptc—I —ISmo —> Wg

Question 18

what is molecular characterisation od Hh Ptc Smo and Wg

Answer 18

Hh is secreted signalling molecule
Ptc and Smo are transmembrane proteins
Ci is transcription factor required for Wg expression