1

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).

2

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 involved2) If each gene is X-linked or autosomal 3) If the mutant or wild-type allele for each is

dominant4) If genes are linked or assorting

independently5) Map distances between all linked genes

3

Wild-type Drosophila melanogaster

Red eyesLong wings‘Gray/ tan’ bodySmooth bristles

4

Traits Studied

Miniature wings ( m )

Forked bristles ( f )Singed bristles (sn)

+

sn

5

Traits Studied

Scarlet eyes (st)

White eyes (w)

wild type (+)

Brown eyes (bw)

6

Traits Studied

Wild type (+) Yellow bodies (y) Ebony bodies (e)

7

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

8

Finding Information about Traits

9

10

Finding Information about Traits

11

Finding Information about Traits

12

Finding Information about Traits

13

Finding Information about Traits

14

Finding Information about Traits

15

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 identifiedcomprehensive genetic mapgenome sequencedmany genes comparable to humans

16

Viewing and Anesthetizing Flies

Binocular dissecting microscopesocular focus, zoom

Carbon dioxideanesthetizing needlesanesthetizing platformsTurn off CO2 before leaving lab

MITES!!! Wipe down everything with ethanol (70%)even when not working with

flies

17

Fly Care and Maintenance

Feeding - Instant Drosophila MediumSterile vials and plugs

Transfer flies to new vials with new foodStocks - Every two weeksCrosses - Every 3-4 days, until larvae in

first vials

Incubator 24OC (Room temperature for now)

18

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,

19

Sexing Flies

Male Female

20

Sexing Flies

http://www.bio.ilstu.edu/Edwards/other/Sexing_Drosophila.shtml

Sex combs are only seen in males

21

Sexing Flies

http://www.bio.ilstu.edu/Edwards/other/Sexing_Drosophila.shtml

Genital arch in males

22

Sexing Flies

Male Female

23

Life Cycle

Pupae Eggs

Larvae

24

Life Cycle

25

Virgin Collection

Adults emerge from pupal cases (eclose)Males not ready to mate for 8-10 hrFemales ready immediately

Clear Vials before 9 AM

Return within 8 hours

Separate males and females into separate vials

26

Lab Supplies and Access

Main Lab

Tour of Fly Room

Key Pad - 3334

27

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.