sexual and morphological variations in d.melanogaster
TRANSCRIPT
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