Lecture 17 Flashcards
Forward Genetics vs Reverse Genetic?
Forward: Go from phenotype to genotype
Reverse: Go from genotype to phenotype
Easiest to grow vs Hardest to grow order them?
Yeast
C.elegans
D.melanogaster
Danio Rerio
Mouse
(opposite is most like humans)
What organisms are least like humans?
Those that are the most divervent
Yeast
-Eukaryotic, unicellular
-Diploid/Haploid
-2-3 hour generation time
-Asexual or sexual reproduction
-Can be frozen
Generation Time?
-Time needed to produce an offspring that is also able to reproduce
Yeast life cycle?
- Can exist as haploid (a strain or alpha strain). Can reproduce asymmetrically to produce identical daughter
- Diploid yeast can reproduce asexually to make diploid yeast
- Diploid can undergo sporulation in stress which produces haploid
C.elegans
-invertebrate
-Multicellular
-3 days generation time
-translucent
-Can be frozen
Invariant development of C.elegans
Each c.elegan has 1090 cells that are each developped in the same exact order inn every worm
Sexes of C.elegans?
Hermaphrodite(XX): can produce asexually (XX) can spontaneously produce males (XO)
Males(XO): Produce sexually with XX
C.elegan life cycle?
- Eggs laid
- Embryonic development (14hrs)
- Larvae produced
- Larvae grow over a day
Dauer State of C.elegans?
When stressed C.elegans go into frozen hybridization state where they don’t eat or do anything
D.melanogaster
-Invertebrates
-Multicellular
-Have body axis(anterior/posterior)
-CNS, digestive system
How many genes ddo fruit flies share with humans?
75%
Danio Rerio
-vertebrate
-Generation time 2-3 months
-Translucent embryos + larva
What are dani rero used for?
-Have gills so it is very easy to treat them with drugs and then do toxicity screens on them
Mouse
-Vertbrate
-3 month generation time
Emergin model organisms?
-Do things humans can’t do
Ex. Axolotyl and Planaria
Axolotyl
-Can cut off a limb and it will regenerate a new limb
Planaria
-Can cut into three sections and each section will grow an entirely new worm
Randy Scheckman
Discovered COP II vesicles ( coat and all the proteins)
After the pulse where are the proteins?
ER
After a 3 min pulse + 10 min chase where are the proteins?
Golgi
After a 3 min pulse + 40 mins where are the proteins?
Secretory vesicles
T/F: If you mutate genes involved in secretion the organism is most likely going to die?
True
Temperature sensitive mutations?
Affect the genes at one temperature but not the other
Permissive temp vs restrictive?
Permissive : organism is wild type
Restrictive: Mutant phenotype
How many total sec mutants are there?
50
How do sec mutants differ?
-Some make the ER swollen
-Some made vesicles trapped between ER/Golgi
-Some made the golgi swollen
-Some had a bunch of vesicles in PM
What type of mutant was Sec1?
bunch of secretory vesicles inside the plasma membrane but they could not fuse with the plasma membrane and release their contents
How to test if two yeast have mutations in the same genes?
Complementation
If sec 13 and sec23 are mutations on the same gene….
They will not complement and will produce mutant phenotype
If sec13 and sec23 are not mutations on the same gene…
They will complement and produce a wild type phenotype
Two human genes homologous to yeast Sec23?
Sec23a and Sec23b
Cranio-lenticulo sutural dysplasia
Amino acid change in Sec23A from phenylalanine to leucine
-Vesicles are unable to bind their coat proteins
