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Unformatted text preview: Welcome to Bio 2322
Genetics Laboratory Tuesdays & Thursdays Contact Information: Nisha Hariharan firstname.lastname@example.org Subject of the email should be "genetics lab" Office Hours: Monday 4 to 5 pm INTRODUCTION TO DROSOPHILA Drosophila melanogaster Twowinged insect Common fruit fly Genus is Drosophila species is melanogaster About 1500 species known Belongs to Diptotera the order of flies 3 body segments: Head, Thorax and abdomen head Thorax Abdomen Nomenclature Genus begins with a capital letter, while species begins with a lower case letter Drosophila melanogaster Good model organism in Genetics owing to Small size(23 mm) Easy to culture in the laboratory Short generation time Single female lays as many as 500 eggs Numerous mutant genes to study Lot of background information available Entire genome has been sequenced Drosophila Genome 4 pairs of chromosomes 3 autosomal pairs 2 sex chromosome Life cycle Four distinct stages: Egg, Larva, Pupa and Adult Exhibits complete metamorphism Temperature 2123 degree C Day 0: Female lays eggs Day 1: Eggs hatch Day 2: First instar Day 3: Second instar Day 5: Third and final instar (two days in length) Day 7: Pupariation (pupal formation) Day 1112: Eclosion (adults emerge from the pupa case) Females become sexually mature 810 hours after eclosion Drosophila melanogaster Larvae Pupae Wild type Drosophila Full red eyes Beige colored body Full round wings that pass beyond the abdomen A deviation from any of these characteristics is considered a mutant for the particular trait Wild type Symbolism For "lower" organisms such as insects, the Dominant &/or most common trait is called the Wild Type which is designated as +/+ Recessive trait is called the Mutant Type which is designated with the abbreviation of the mutant trait. Ex: Vestigial = vg (vg/vg) Sepia = se (se/se) 1. Eye Color: * Wild Type (+): Full, Round Red Eyes Mutants:
Sepia Eyes (se): Full, Round, Brown White Eyes (w): Full, Round, White Bar Eyes (B): Irregular, Red Scarlet Eyes (st): Full, Round, Bright Red Eyeless (ey): Small, Round, Red 2. Wing Shape: * Wild Type (+): Full, Round Wings Mutants: 3. Body Color: * Wild Type (+): GrayishBeige Colored Body Mutant: Ebony Body (e) Black Colored Body Sexual Differences
Sexually dimorphic Size Females bigger than males Abdomen Shape Female abdomen is pointed, while male abdomen is more rounded Banding Pattern Female dorsal portion has alternating light and dark bands, while male dorsal portion has fused bands Sex Combs in males identify sex Male and Female ...
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- Spring '08