sexual and morphological variations in d.melanogaster

INTRODUCTION TO

DROSOPHILA MELANOGASTER

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Diptera

Family: Drosophilidae

Genus: Drosophila

Species: D. melanogaster Meigen 1830

DROSOPHILA MELANOGASTER

use of D. melanogaster was developed

by Thomas Hunt Morgan (1910)

crossing-over

Genes are linked in a linear array

along chromosomes and the

probability of recombination occurring

between any two genes is related to

the distance that separates them

DROSOPHILA MELANOGASTER

Alfred A. Sturtevant

frequency of recombination between two

linked genes can be used to estimate the

distance between them

trihybrid cross to show that distances are

additive and can be used to construct a map

to describe the order and placement of genes

along a chromosome

DROSOPHILA MELANOGASTER

simple culture requirements

short generation time

copious offspring

well-defined genetics

AS A MODEL ORGANISM

LIFE CYCLE

LIFE CYCLE

DROSOPHILA MELANOGASTER

EYE COLOR

pteridine

ommochrome

DROSOPHILA MELANOGASTER

EYE COLOR

Etherize the jar (sideways)

exposure time 3-5min

Keep the jar sideways to prevent flies from landing in

the medium

!! FLIES CAN BE OVER ANESTHESIZED RESULTING TO

STERILITY OR DEATH !! Do not over expose

Flies remain unconscious at least 20 minutes

HANDLING FLIES

examine various phenotypes or determine the sex of

an individual fly. To accurately score flies for

phenotype differences that are difficult to

distinguish, it is easiest to make direct comparisons

by having a wild type fly and the mutant strain both

in the field of view

SCORING PHENOTYPES

♀ larger

tip of abdomen is

pointed and elongated

♂ tip is rounded

darker abdomen

presence of sex combs

DETERMINING SEX OF ADULT FLIES

DETERMINING SEX OF ADULT FLIES

DETERMINING SEX OF ADULT FLIES

SEXUAL AND MORPHOLOGICAL

VARIATIONS