Drosophila melanogasterNomenclature

Advanced Genetics 2/14/19

Why study flies?

• Fast life cycle (2 weeks)• Many behaviors/phenotypes to

study!

http://modencode.sciencemag.org/drosophila/introduction

Phenotypes

• Non-italicized • Describe animals:• Appearance• Behavior

• Examples:• White (eyes)• Notch (wings)• Fruitless (sexual behavior)

http://www.bio.miami.edu/dana/250/250SS16_14.html

Genes• Named for mutant phenotype

• Lower case if named for recessive mutant (ex: white (w))• Upper case if named for dominant mutant

(ex: Shaker (Sh))

• Italicized (both genes and alleles):• Gene name: fruitless• Gene symbol: fru• Placeholder name: CG14307

https://link.springer.com/chapter/10.1007/978-1-4939-3777-6_1

Mutations

• Relative to wild type (fru+)• X linked written as superscripts to

the X chromosome• Xw (white gene on X chrom.)

• Alleles• Superscripted numbers: fru1, fru2, fru3• Alternatively: fru[1], fru[2], fru[3]• Note: may be omitted or shorthanded

(fru*, fru-) in some cases

http://dev.biologists.org/content/130/17/4001

Genotype

• Relative to wild type• Alleles listed in order of the standard

genetic map • X;Y;2;3;4

• Genes separated by spaces• Homologous chromosomes separated by a / and homozygous

chromosomes are defined only once• y1 w1 f1 implies y1 w1 f1 / y1 w1 f1

• Non-homologous chromosomes separated by a ;• bw1; e1; ey1

Balancer Chromosomes • Help preserve linkage—important genetic tool!• Many types: https://bdsc.indiana.edu/stocks/balancers/balancer_intro.html (Cyo,

SM6, TM3, etc.)• Carry dominant visible marker and multiple, overlapping inversions, and recessive

deleterious mutations • No viable progeny with recombinants on this chromosome• Progeny that don’t carry the marked chromosome must have the unmarked, non-

recombined chromosome

Proteins

• Non-italicized• Capitalized• Same names/symbols as

genes• Example:• Gene/gene symbol: hedgehog/hh• Protein/protein symbol:

Hedgehog/Hh

http://www.genetics.org/content/184/3/731

FlyBase—useful tool

Drosophila Strains• Use FlyBase• Order through BDSC

Resources

• https://bdsc.indiana.edu/stocks/index.html

• http://flybase.org/ http://www.cgslab.com/phenotypes/

Mutant Phenotype Encyclopedia