In Drosophila gray body color is dominant to ebony body colo

In Drosophila, gray body color is dominant to ebony body color, while long wings are dominant to vestigial wings. Assuming that the P_1 individuals are homozygous, work the following crosses through the F_2 generation, and determine the phenotypic each generation. Enter your answers in fraction form (ex: 1/4) in the blanks provided by the list of phenotypes: gray, long gray, vestigial ebony, long ebony, vestigial

Solution

In Drosophila, gray color is dominant to ebony body color, while long wings are dominant to vestigial wings. Assuming that the P1 individuals are homozygous, work the following crosses through the F2 generation, and determine the phenotypic ratios for each generation

E = gray; e = ebony

V = long; v = vestigial

It is a dihybrid cross, in which phenotypic ratio should be 9:3:3:1

P1: ----> EEVV (homozygous dominant) *eevv (homozygous recessive)

F1 generation offspring are all are EeVv representing ---> heterozygous for both traits (genotype and
dominant phenotypes); therefore, all gray body & and long wings can be seen as phenotypic appearance.
P1 dihybrid cross: Punnet square

*                ev   ev    ev         ev
EV          EeVv EeVv EeVv EeVv
EV          EeVv EeVv EeVv EeVv
EV          EeVv EeVv EeVv EeVv
EV         EeVv   EeVv EeVv EeVv

F2 –generation -dihybrid cross:

*              EV      Ev    eV           ev
EV          EVEV EVEv EVeV EVeV
Ev          EEVv EEvv EeVv Eevv
eV          EeVV EeVv eeVV eeVv
ev          EVev Evev eVev evev


Genotypic ratios ----> 1/16 EEVV; 1/8 EEVvl; 1/16 EEVV; 1/8 EeVV; 1/4 EeVv; 1/8 Eevv; 1/16 eeVV ;1/18 eeVv; 1/16 eevv

Phenotypic ratio ---->

9/16 gray body and long wings

3/16 gray body and vestigial wings

3/16 ebony body and long wings

1/16 ebony, vestigial

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