Fly Project Begins
Objectives:
Organize groups - 4 members maximum
Start notebooks - Describe traits and strains, etc.
Understand traits and obtain needed flies - Purebreeding
Learn about handling flies Feeding , Anesthetizing
Sexing, Virgin collection
Set up stock of each strain
For September 18,
obtain 10 virgin females of each strain (wild type, w sn m e).
1
Inheritance in Drosophila melanogaster
Project
Investigate genes responsible for four traits:
white vs. red eyes; miniature vs. normal wings;
ebony vs. tan body color,
singed vs. normal bristles
Determine:
1) Number of genes involved
2) If each gene is X-linked or autosomal
3) If the mutant or wild-type allele for each is dominant
4) If genes are linked or assorting independently
5) Map distances between all linked genes
2
Wild-type Drosophila melanogaster
Red eyes
Long wings
‘Gray/ tan’ body
Smooth bristles
3
Traits Studied
Miniature wings ( m )
Forked bristles ( f )
Singed bristles (sn)
+
sn
4
Traits Studied
Scarlet eyes (st)
White eyes (w)
wild type (+)
Brown eyes (bw)
5
Traits Studied
Wild type (+)
Yellow bodies (y)
Ebony bodies (e)
6
Crosses to be Performed
Reciprocal crosses:
strain A
x strain B
;
strain A
x
strain B
F1 x F1 crosses ( F1 female x F1 male ):
If all X-linked or independently assorting
Testcrosses ( F1 female x strain A or strain B male ): Mapping
F1
x
pure-breeding recessive
7
Finding Information about Traits
8
9
Finding Information about Traits
10
Finding Information about Traits
11
Finding Information about Traits
12
Finding Information about Traits
13
Finding Information about Traits
14
Reasons for Studying D. melanogaster
Small size
Short generation time (10 days - two weeks )
Easy maintenance
Number of well characterized traits
13,601 protein-encoding genes identified
comprehensive genetic map
genome sequenced
many genes comparable to humans
15
Viewing and Anesthetizing Flies
Binocular dissecting microscopes
ocular focus, zoom
Carbon dioxide
anesthetizing needles
anesthetizing platforms
Turn off CO2 before leaving lab
MITES!!! Wipe down everything with ethanol (70%)
even when not working with flies
16
Fly Care and Maintenance
Feeding -
Instant Drosophila Medium
Sterile vials and plugs
Transfer flies to new vials with new food
Stocks - Every two weeks
Crosses - Every 3-4 days, until larvae in first vials
Incubator 24OC (Room temperature for now)
17
Fly Management and Supply Cleaning
Morgue - unwanted adults -
Freezer - unwanted cultures with potential larvae -
Vial and Plug Washing thawed vials rinsed with warm water,
medium dissolved, brushed from vial,
plugs rinsed with warm water until clean,
18
Sexing Flies
Male
Female
19
Sexing Flies
Sex combs are
only seen in
males
http://www.bio.ilstu.edu/Edwards/other/Sexing_Drosophila.shtml
20
Sexing Flies
Genital arch in males
http://www.bio.ilstu.edu/Edwards/other/Sexing_Drosophila.shtml
21
Sexing Flies
Male
Female
22
Life Cycle
Pupae
Eggs
Larvae
23
Life Cycle
24
Virgin Collection
Adults emerge from pupal cases (eclose)
Males not ready to mate for 8-10 hr
Females ready immediately
Clear Vials before 9 AM
Return within 8 hours
Separate males and females into separate vials
25
Lab Supplies and Access
Main Lab
Tour of Fly Room
Key Pad - 3334
26
Before Leaving Lab Tuesday
Everyone in group must know how to:
feed, transfer, anesthetize flies
distinguish mutant traits from wild type
collect virgins
Plan -
who will find information about each trait;
times when each member will be in lab to clear, etc.
By September 18 - Make sure you have 10 virgin females from
each strain and 10 males from each strain for reciprocal
crosses, which will be set up in lab.
27