You are interested in observing independent assortment in Dr

You are interested in observing independent assortment in Drosophila melanogaster. You have established a true-breeding mutant line with curved wings (c), which is controlled by a single gene on chromosome 2, and sepia eyes (se), which is controlled by a single gene on chromosome 3. You establish a parental cross between true-breeding males with curved wings and sepia eyes and true-breeding wild-type females. You then mate the F1 males and females to generate the F2 offspring. Map out this cross below, including expected genotypes and phenotypes of males and females at all stages of the experiment. Include the expected phenotypic ratio for the F2 generation.

Solution

Curved wings[c] , sepia eyes [se]

cc sese males               x                      CC Se Se Female

CcSese                                    [F1]

CcSese                                    x                      CcSese

Gemets

CSe

Cse

cSe

cse

CSe

CCSeSe Wild type

CCSese Wild type

CsSeSe Wild type

CcSese Wild type

Cse

CCSese Wild type

CCsese wild wings and sepia eyes

CcSese Wild type

Ccsese wild wings and sepia eyes

cSe

CcSeSe Wild type

CcSese Wild type

ccSeSe Curved wings and Wild eyes

ccSese Curved wings and Wild eyes

cse

CcSese Wild type

Ccsese wild wings and sepia eyes

ccSese Curved wings and Wild eyes

Ccsese Curved wings and sepia eyes

Now we can see according the rule on impendent assortment each genotype will assort, which must have to follow 9:3:3:1 phenotypic ratio and 1:1:2:2:4:2:2:1:1 genotypic ratio.

Wild type = 9

Curved wings and Wild eyes =3

Wild wings and sepia eyes =3

Curved wings and sepia eyes =1

CCSeSe = ccsese= ccSeSe = CCsese =1

CCSese = CcSeSe =CcSese= Ccsese=2

CcSese= 4

Gemets	CSe	Cse	cSe	cse
CSe	CCSeSe Wild type	CCSese Wild type	CsSeSe Wild type	CcSese Wild type
Cse	CCSese Wild type	CCsese wild wings and sepia eyes	CcSese Wild type	Ccsese wild wings and sepia eyes
cSe	CcSeSe Wild type	CcSese Wild type	ccSeSe Curved wings and Wild eyes	ccSese Curved wings and Wild eyes
cse	CcSese Wild type	Ccsese wild wings and sepia eyes	ccSese Curved wings and Wild eyes	Ccsese Curved wings and sepia eyes